BOVINE

Question 1

A 6-month old feedlot steer, which entered the feedlot 4 weeks ago, has lost weight and is now showing an enlarged left flank as shown in the image below. On exam, you find the left side of the abdomen to be gas-filled under moderate pressure, and the rumen to be otherwise poorly filled and with poor motility. Based on percussion and auscultation, the animal also appears to have chronic bronchopneumonia. What is the most likely cause of the rumen malfunction?

a. Free gas bloat, failure to eructate
b. Frothy bloat
c. Type 3 vagal indigestion
d. Cecal dilation
e. Left displaced abomasum

Answer 1

a. Free gas bloat, failure to eructate

This is sometimes called Type 1 vagal indigestion, or free gas bloat. It is frequently associated with swollen mediastinal lymph nodes caused by pneumonia. The signals to or from dorsal rumen receptors, which detect gas pressure and open the cardia, are compromised such that eructation does not occur normally and free gas bloat occurs. This in turn causes the calf to feel full and it eats poorly and loses weight. One needs to treat the pneumonia and perhaps create a temporary rumen fistula to allow the escape of gas until eructation returns to normal.

Question 2

You examine several dairy calves which have developed areas of hair loss and thick grayish skin (see image). It is winter, and these are 2-month old housed calves. They appear to be otherwise healthy and growing normally, but the owner would like a diagnosis and treatment.

a. Ringworm
b. Lumpy skin disease
c. Lice
d. Mange
e. Warts (papillomatosis)

Answer 2

a. Ringworm

Ringworm is a dermatomycosis that tends to occur most commonly in housed, crowded calves in winter when there is little UV light present. The most common dermatophyte in cattle tends to be Tricophyton verrucosum, with T. mentagrophytes second most common. Therapy includes such topical treatments as captan, diluted bleach, lime sulfur, or miconazol shampoos. Systemic treatment is rarely needed.

Question 3

An outbreak of psoroptic mange is identified in a herd of cattle . What is the treatment of choice?

a. Ivermectin
b. Pyrethrin
c. Levamisole
d. Albendazole

Answer 3

a. Ivermectin

Albendazole and levamisole are used to treat worms. Ivermectin is more effective than pyrethrin

Question 4

During a visit to a dairy, several cows are noted to have 1-3 cm cysts on their backs with small holes at the center resembling breathing pores created by larvae. If these are breathing pores, what organism are the cows infected with?

a. Sarcophaga
b. Simulium
c. CUlicoides
d. Anopheles
e. Hypoderma

Answer 4

e. Hypoderma

The correct answer is Hypoderma bovis or H lineatum. Hypoderma is also known as the cattle grub, heel fly, or warble fly. The life cycle begins with the female attaching up to 500 eggs to the hairs around the hocks and lower portions of the cow. First-stage larvae will hatch in just a few days and burrow into the skin. At this point, they begin their tour de cow and migrate towards the epidural fat in the spinal canal(H bovis) or via the esophagus (H lineatum). After several months in this beautiful location, they become L2s and migrate to the subcutaneous tissues of the back where they will molt once more, and become L3s. Once they are L3s, the swelling on the cows’ backs can be felt. After 5-11 weeks, the L3s mature and burst through the skin, dropping on the ground where they will become adults in another 1-3 months. Sarcophaga spp are known as the flesh flies. An adult female will deposit her eggs in wounds and ulcers; the larvae then feed off the wounds. Eventually, they mature into L3s and fall off to pupate on the ground.
Simulium flies are also known as buffalo gnats or black flies. Adult females are the key problem with these flies because they suck blood! They prefer the legs, abdomen, head, and ears. Additionally, they will only eat during daytime. Female flies are an annoyance to cows and cause decreased productivity.
Anopheles are just mosquitoes; however, they are the most important vectors of human malaria and spread West Nile Virus.
Culicoides are also known as no-see-ums, biting midges, and punkies. They are a great annoyance to cows and have the potential to transmit bluetongue and Onchocerca. In horses, they are thought to be the cause of sweet itch, a Type I hypersensitivity to their saliva.

Question 5

Each year, hide damage due to this organism results in tremendous economic loss in cattle.

a. Hypoderma bovis
b. Sarcopetes scabiei
c. Chochliomyia hominivorax
d. Ornithodoros coriaceus

Answer 5

a. Hypoderma bovis

H bovis is also known as the cattle grub, heel fly, or warble fly. The life cycle starts with the female attaching up to 500 eggs to the hairs around the hocks and lower portions of the cow. First-stage larvae will hatch in just a few days and burrow into the skin. At this point, they migrate towards the epidural fat in the spinal canal (H bovis) or via the esophagus (H lineatum). After several months, they become L2s and migrate to the subcutaneous tissues of the back where they will reach puberty, molt once more, and become L3s. Once they are L3s, swellings on the cows' backs can be felt. After 5-11 weeks, the L3s mature and burst through the skin, dropping on the ground where they will become adults in another 1-3 months.
Cochliomyia hominivorax (aka screwworm) lays its eggs on skin wounds. The developing maggots feed on the flesh and can lead to multiple infestations from additional screwworms and other flies.
Ornithodoros coriaceus (aka Pajahuello tick) is a soft tick that feeds on many different mammals and birds. This tick has become somewhat famous because it appears to transmit epizootic bovine abortion.
Sarcoptes scabiei (aka scabies mange mite) causes mechanical and chemical irritation and intense pruritus, leading to loss of milk production and damage of hides due to scratching. Although this is a possible answer, the economic impact of Sarcoptes scabies is not as worrisome as with Hypoderma bovis.

Question 6

A 5-year old cow presents with skin lesions confined to the nonpigmented areas (see image). The affected skin is dry and raised at the periphery. The skin of the teats appears dry. Which of the following could result in this presentation?

a. Ingestion of Pteridum aquilinum (bracken fern)
b. Ingestion of Quercus spp.
c. Ingestion of lupine
d. Ingestion of moldy feed containing aflatoxins

Answer 6

d. Ingestion of moldy feed containing aflatoxins

This is a case of photosensitization based on the skin lesions confined to the nonpigmented areas. Primary photosensitization can occur when photodynamic agents are absorbed from the G.I. tract such as Hypericum perforatum (St. John’s wort), Fagopyrum esculentum (buckwheat), Ammi majus (bishop’s weed), and Cymopterus watsonii (spring parsley). Secondary (hepatogenous) photosensitization occurs when the liver’s excretion of phylloerythrin is impaired due to liver damage. Phylloerythrin is derived from the breakdown of chlorophyll by rumen microbes. The best answer in this question is aflatoxins because they are known to cause liver damage.

Bracken fern toxicity causes acute hemorrhagic syndrome in cattle. Lupine toxicity primarily causes birth defects. Quercus (oak) toxicity causes GI and renal dysfunction.

Question 7

You are presented with a Longhorn steer with a large bloody sore on its left side just behind the scapula (see image). There is pus and serum mixed with blood. Once you clean away this material, there appears to be a large open superficial sore, slightly raised (excoriated granuloma). The impression smear you make is full of intracellular pleomorphic gram positive rods. What organism is causing this lesion?

a. Onchocerca cervicalis
b. Staphylococcus aureus
c. Streptococcus bovis
d. Corynebacterium pseudotuberculosis
e. Corynebacterium bovis

Answer 7

d. Corynebacterium pseudotuberculosis

The lesions of C. pseudotuberculosis in cattle, horses, sheep and goats are all rather different by species. In horses one sees pectoral and ventral abscesses, or even internal abscesses. In sheep and goats, the organism causes caseous lymphadenitis.

In cattle, as seen here, the lesions tend to be on the sides, perhaps initiated by a skin scratch from a fence. Most lesions heal spontaneously in 3 to 4 weeks and, although they attract flies, they are not a significant disease in cattle.

Question 8

The owner of a nearby dairy calls to have a wound on his heifer inspected. The wound is located ventrally, on the brisket, and there are larvae feeding on the tissue. The wound is approximately 5cm in diameter and has now become 6 cm deep as a result of larval feeding. As you approach the cow, you see a large, metallic blue-green colored fly leaving the wound. What is your diagnosis?

a. Chrysops
b. Cochliomyia hominivorax
c. Stomoxys calcitrans
d. Tabanus

Answer 8

b. Cochliomyia hominivorax

This fly is also known as the screwworm. Females lay hundreds of eggs at the edge of fresh wounds on the cow; the larvae hatch in approximately 24 hours. As the larvae eat the living tissue, they create a huge wound. Screwworm larvae then fall off and pupate, completing their life cycle in approximately 21 days. This fly is reportable!

Question 9

A 3-year old Jersey dairy cow presents 8 days after parturition with decreased milk production, anorexia, teeth grinding, episcleral injection, and colicky behavior. On physical exam, you observe distention of the right flank, a wide region of right sided monotone pinging from the 9th rib to behind the 13th rib and extending down in a line from the hip to the elbow at the 9th rib, and no rumen contractions. On rectal exam, you note normal-appearing feces and a large turgid structure palpable to the right of midline and as far forward as you can reach. The cow is negative for xiphoid pain. Temperature is 103.3F (39.6 C) degrees, HR=98, and respiration is 44. What is the most likely diagnosis?

a. Cecal displacement or volvulus
b. Gas in the spiral colon
c. Abomasal torsion
d. Intussusception

Answer 9

c. Abomasal torsion

he clinical signs described are classic for an abomasal torsion. These are much less common than left or right displaced abomasum. However, the risk factors for developing abomasal torsion appear to be the same. This finding is a surgical emergency and must be corrected before cows go into shock. Another factor is that many times you may be able to palpate abomasal torsion rectally, but not always (esp difficult in large Holstein cows).
Cecal displacement and cecal volvulus can be ruled out because you would likely be able to palpate these disease processes via rectal examination as a soft loaf of bread that you can get all the way around. The ping is usually high in the right flank and does not extend to the 9th rib on a line from hip to elbow. Animals with intussusception are very colicky and have scant dark red feces. The intussusception can be found sometimes by rectal palpation as a firm painful mass. Gas in the spiral colon is a frequent finding in any sick cow with poor GI motility and is not a primary disease problem. It is diagnosed by finding an 8-inch circular ping high on the last rib or just behind it.

Question 10

Recently, there has been an outbreak of several cows with an acute onset of ataxia, nystagmus, circling, strabismus, and depression followed by strange behavior, vocalization, convulsions, and death in just two days. A few cows appear to be initially less severely affected and have intense pruritus and alopecia which is then followed by similar clinical signs as above. The only recent change in environment is the acquisition of fifty pigs that are housed close by. What is the most likely diagnosis?

a. Rabies
b. Salt poisoning
c. Pseudorabies
d. Polioencephalomalacia
e. Hypomagnesemia

Answer 10

c. Pseudorabies

This question is kind of tough because all the choices are great differentials. The key here is the history of introducing new pigs and the pruritus with alopecia. Pigs are the primary host of pseudorabies and are usually asymptomatic. Some of these pigs were probably infected and being in close proximity somehow the disease has been introduced to the cattle. Even though there is an outbreak going on, it is probably not going to be self-perpetuating among the cattle since they don’t shed virus for long periods of time. In cases that are not as peracute to acute the first clinical signs are often paresthesia hence the name “Mad Itch”. However, you must be careful because sites of rabies virus inoculation are also pruritic and result in alopecia from scratching. Unfortunately, there is no treatment and most affected animals die. The best thing to do is remove the pigs.

Question 11

You visit a dairy that has ongoing problems with mastitis. They ask you for advice on proper milking and maintenance of equipment. Which of the following statements is INCORRECT?

a. Replace the liner every 25 milkings
b. Post dip all teats
c. Shut off vacuum before removing the claw
d. Pre dip all teats
e. Fore strip each quarter

Answer 11

a. Replace the liner every 25 milkings

This is the best answer because the liner will last for at least 500 milkings. There are three types of liners: synthetic rubber, natural rubber, and silicone. These are designed to last anywhere between 500 and 10,000 milkings. Post-milking teat disinfection is probably the most effective way of reducing the rate of contagious mastitis. Pre-milking dip will help control environmental mastitis.

Question 12

You are at a dairy trying to solve a mastitis problem. You perform a physical exam on a cow with mastitis and notice serum-like secretion with clots from two of the teats, and the affected quarters are hot and swollen. What can you tell the dairyman with a fair degree of confidence about the type of mastitis this is likely to be?

a. This cow is infected with a fungus
b. This cow is infected with Arcanobacterium pyogenes
c. This cow is infected with a coliform
d. This cow is infected with a contagious pathogen

Answer 12

c. This cow is infected with a coliform

This is a typical secretion with coliform mastitis.

Question 13

A dairy farmer brings you a 6-week old calf for postmortem exam on a nice warm spring day. He has had three 5- to 7-week old calves die in the last week and this one just died an hour ago. They show depressed appetite, fever, and rapid labored breathing before collapsing within a day from the time the first signs are noticed. The calves were born on his farm and have been in good well-ventilated individual hutches with shade. They are fed 12% of their body weight per day in whole milk, plus a calf starter grain, alfalfa hay and free choice water. The major lesions are serosal and subcutaneous petechial hemorrhages and heavy wet red lungs (see image). Based on these pathologic findings, which of the following is the most likely cause of death?

a. E. coli septicemia
b. Bovine virus diarrhea (BVD)
c. Mannhemia hemolytica bronchopneumonia
d. Salmonella dublin
e. Malignant catarrhal fever (MCF)

Answer 13

d. Salmonella dublin

S. dublin tends to cause septicemia in dairy calves 4 to 8 weeks of age, and the lesions described are typical. The organism can be transmitted by carrier cows to neonates at birth or via their milk. The most effective control measures are to cull carriers and vaccinate calves using a modified live S. dublin vaccine.

Question 14

Which of the following medications has the shortest meat withdrawal time in beef cattle?

a. Sulfadimethoxine
b. Oxytetracycline
c. Penicillin G
d. Chloramphenicol
e. Ceftiofur

Answer 14

e. Ceftiofur

Question 15

One cold December morning you are presented with a 5-year old Holstein dairy cow which freshened the day before. This morning she was found down in the corral and unable to rise. On physical examination you find T=98F, 36.7C, HR=90 (and the heart is difficult to hear), and RR=10. She has her neck turned back toward her thorax, and it has an “S” shaped curve in it. Her nose is dry, she is non-responsive to being handled, and her rumen motility is absent. The rectal exam shows that her bladder is full. The mammary glands and the uterine lochia appear normal.

Based on these findings, which of the following disorders is most likely?

a. Coliform mastitis
b. Milk fever
c. Left displaced abomasum (LDA)
d. Hypothyroidism
e. Spinal lymphoma

Answer 15

b. Milk fever

A cow with a history of recent parturition with clinical signs such as these should be considered as having hypocalcemia until proven otherwise. The cow needs treatment to restore normal calcium levels.

Question 16

One 3-week old calf in a group of young calves being fed milk replacer has been depressed, growing poorly and appears unthrift with a rough hair coat. She recently began kicking at her flank, teeth grinding, and vocalizing with an arched back. She has developed white, putty-like feces and is dehydrated. Which of the following is the most likely underlying cause of the problem?

a. Excessive carbohydrate in the milk replacer
b. Intussusception of the small intestine
c. Congenital rumen stasis
d. Dysfunction of the esophageal groove
e. Atresia coli

Answer 16

d. Dysfunction of the esophageal groove

This is a typical description of esophageal groove dysfunction in a calf resulting in rumen acidosis.

To review normal physiology, the esophageal groove (also known as reticular groove) is a specialized part of the ruminant stomach that closes in response to drinking milk, directing it directly to the abomasum. When dysfunctional, milk goes to the rumen where it is fermented by rumen microbes and converted to volatile fatty acids and lactic acid. The resulting rumen acidosis leads to the clinical signs described in this case. For this reason, this phenomenon is sometimes referred to as rumen drinking.

For this reason, this phenomenon is sometimes referred to as rumen drinking.

Question 17

A three-year old Jersey cow presents for decreased milk production and weight loss. On physical exam, a hard, non-painful swelling of the mandible is identified. Radiographs of this region show lysis and productive bone lesions, with distortion of the teeth in the area. What is the most likely cause for these findings?

a. Osteosarcoma
b. Vesicular stomatitis
c. Actinomycosis
d. Actinobacillus lignieresii

Answer 17

c. Actinomycosis

This cow has become infected with Actinomyces bovis (lumpy jaw) as a result of sustaining an injury in the mucous membranes, often from eating hard scabrous feeds. Actinomyces bovis is part of the normal oral and rumen flora and can become a source of infection when cows consume items that traumatize their mouths. The lesion classically causes a hard non-painful swelling of the mandible or maxilla along with productive and destructive bony changes. Teeth may be lost. Osteosarcoma is very uncommon in cattle and is therefore a poor answer choice. Vesicular stomatitis will not cause a hard non-painful swelling. Instead, you may see oral ulceration as a result of ruptured vesicles along the tongue. This virus can also cause lesions of the feet and teats. Cows infected with vesicular stomatitis will most likely be salivating, not eating, depressed, and febrile. Actinobacillus lignieresii is the causative agent of woody tongue. In this case, you would expect to see a large firm tongue on physical exam. Sodium iodide has been used to treat lumpy jaw, but this will only arrest the lesion.

Question 18

You are called by a beef rancher located in the northern California oak foothills one day in March after an unusual spring snowstorm that dumped a foot of wet snow two days earlier. You are asked to diagnose and treat several calves in the 3- to 5- month old age range which are listless and weak. You do a physical exam and find elevated heart and respiratory rates, but normal rectal temperatures. The most remarkable finding is marked edema of the perineum and vulva of the calves (see image).
What is the best diagnosis based on these signs and history?

a. Acute oak toxicosis
b. Clostridium hemolyticum infection (redwater)
c. Bovine virus diarrhea
d. Malignant catarrhal fever
e. Lead toxicity

Answer 18

a. Acute oak toxicosis

The reason that oak toxicosis may occur in this scenario is as follows: the snow knocks down the budding oak limbs which are eaten by curious calves who cannot reach the grass. The calves develop both renal and GI signs as the tannins damage the mucosa. Many develop hemorrhagic diarrhea and renal tubular necrosis. Some tannins are hydrolyzed in the rumen to gallic acid and pyrogallol, which are both very toxic to the renal tubules. Treatment is aimed at flushing out the toxins (intravenous fluids) and protecting the gastrointestinal tract. Prevention is best; and the animals will avoid eating the oak if they are offered hay immediately during the storm.

Question 19

Pick the ideal suture pattern for a uterus after a Caesarian section in a cow.

a. Horizontal mattress
b. Simple interrupted
c. Utrecht pattern
d. Near-far-far-near

Answer 19

c. Utrecht pattern

This pattern achieves a nice mucosal and serosal seal when done correctly. Additionally, the exposure of suture to the serosa is minimized with this type of pattern, so adhesions of uterus to surrounding structures is minimized.

Question 20

A beef cattle farm in the mountains of California is experiencing an abortion storm affecting about 50% of heifers. The abortions are occurring primarily in the last trimester. The cows appear healthy; some of the aborted fetuses have hepatosplenomegaly and generalized lymphadenopathy. A necropsy on one of the aborted fetuses shows lymphoid hyperplasia in the spleen and granulomatous inflammation in the liver. In the thymus, extensive macrophage infiltration into the medulla was seen as well as loss of cortical thymoctes. Fetal IgG was markedly elevated. Based on the likely diagnosis, which of the following measures would decrease the future incidence of this problem?

a. Control of Ponderosa pine trees
b. Vaccinate heifers against bovine herpesvirus
c. Avoid feeding silage to heifers
d. Expose heifers to endemic areas before breeding age
e. Control of mosquitoes

Answer 20

d. Expose heifers to endemic areas before breeding age

This is the typical presentation for epizootic bovine abortion (EBA), also known as foothill abortion. The agent causing foothill abortion remains a subject of some investigation but a 2005 molecular study identified a novel deltaproteobacterium as being present in the Ornithodoros coriaceus tick vector and in DNA from fetal thymuses. With EBA, cows usually do not experience abortions again in later pregnancies and exposure to endemic areas before breeding age can also prevent abortions. Other control options may include control of the tick vector or prophylactic antibiotic use.

You can lower your index of suspicion for bovine herpesvirus (Infectious bovine rhinotracheitis virus) because there is no respiratory disease seen in this case; abortions from herpesvirus occur throughout pregnancy and fetuses are typically autolyzed with foci of necrosis in the liver or no gross lesions.

Ponderosa pine needle abortions occur in the last trimester but cows are often moribund after delivery and hemorrhage. There are usually no specific fetal lesions.

Question 21

A cow about one month from term goes off feed and rapidly develops an enlarged, rounded, abdominal shape. She is now uncomfortable and reluctant to move. You examine the cow and note marked accumulation of watery fluid in the uterus. You perform a brief ultrasound and confirm the large volume of fluid in the uterus and a thickened placenta. What should you tell the farmer about this condition?

a. Hydrops amnion (hydramnios) is a disorder of the fetus and although the fetus is unlikely to survive, the cow should be okay
b. Hydrops allantois (hydroallantois) is a disorder of the fetus and can be treated by induction of parturition or Caecarian section and in most cases if the fetus is close to term, the calf will survive and the cow will be fertile
c. Hyprops amnion (hydramnios) is a disorder of the placenta and the fetus is likely to survive but the cow will likely be infertile
d. Hydrops allantois (hydroallantois) is a disorder of the placenta and the prognosis for life of the fetus and fertility of the cow is poor

Answer 21

d. Hydrops allantois (hydroallantois) is a disorder of the placenta and the prognosis for life of the fetus and fertility of the cow is poor

The clinical description is most consistent with hydroallantois because of the rapid accumulation of fluid and the clinical signs of the cow. Hydramnios is a reasonable differential although it more typically involves gradual accumulation of fluid and the cow is usually clinically unaffected.

Hydroallantois is a disorder of the placenta (chorio-allantois) that results in rapid accumulation of 100-200 liters of watery, clear fluid during the last trimester. The cow develops a rounded appearance to the abdomen and it is usually not possible to palpate the fetus or placentomes. The cow often becomes sick with anorexia, decreased rumen motility, dehydration and weakness. She may go down or rupture the prepubic tendon. The prognosis for the fetus is guarded and even with treatment, the cow will likely be infertile. Induction of parturition or C-section are treatment options but the majority of calves are not viable and the dam rarely has normal colostrum. If the pregnancy is terminated, it is unlikely that the cow will have a productive milk cycle. Usually salvage for slaughter is the preferred option unless the fetus is considered valuable and the cow is near term.

Hydramnios is a disorder of the fetus, and the placenta itself is normal. The condition is typically characterized by gradual accumulation of thick viscous fluid during the later part of gestation. The cow develops a pear shaped caudal view. The fetus and placentomes are usually palpable and the cow is usually clinically well. Pregnancy usually goes to term and a small, deformed fetus is delivered. The cow has a fair to good prognosis for life and fertility. The cow may be induced or allowed to go to term depending on her condition.

Question 22

Which immunoglobulin predominates in bovine colostrum?

a. IgG
b. IgE
c. IgA
d. IgM

Answer 22

a. IgG

The correct answer is IgG. It makes up about 85%.

Question 23

About 1 hour after a difficult labor where the calf had to be pulled out with force, the cow goes down. She is pale and her heart rate is 100/min. What happened?

a. Obturator paralysis
b. Pelvic fracture
c. Hypocalcemia
d. Uterine tear

Answer 23

d. Uterine tear

With a traumatic fracture or damage to nerves, the cow would have gone down right away rather than an hour later. Hypocalcemia is possible but less likely in this case where the calf had to be forcibly extracted which can result in a uterine tear, and would be unlikely to make her pale and tachycardic.

Question 24

You are in the process of auscultating a cow that presented for respiratory distress and you hear no breath sounds in the dorsal chest. What is your tentative diagnosis?

a. Pulmonary contusion
b. Aspiration pneumonia
c. Fibrinous pleuropneumonia
d. Pneumothorax

Answer 24

d. Pneumothorax

Since there is free air in the chest, the lung has lost its vacuum and is collapsed. The free air moves dorsally and you are unable to hear any lung sounds. Fibrinous pleuropneumonia will have lung sounds associated with it. Aspiration pneumonia is usually cranioventral in location. Pulmonary contusion is a differential, but given the location, a pneumothorax is more likely.

Question 25

What is the definitive host of Sarcocystis cruzi? a. Sheep b. Horse c. Goat d. Cat e. Dog

Answer 25

e. Dog ## Footnote The ruminant is an intermediate host. Sarcocystis hirsuta involves the cat as the definitive host. Primates are the definitive host for Sarcocystis hominis. The life cycle involves a carnivore eating an infected cow which has cysts in the muscle. Then the cyst eventually forms sporocysts which are shed in feces and subsequently eaten by more cows. The sporocysts then hatch and penetrate artery walls and hang out in the endothelium to develop into sporozoites and eventually become merozoites at which time they invade muscle and encyst as sarcocysts. It takes about 10 weeks for the entire maturation process to occur. Clinical signs are non-specific such as fever, anorexia, salivation, weakness, muscle fasciculations, and weight loss. Diagnosis is likely to be at necropsy; so, prevent carnivore feces from contaminating the area. The definitive host of Sarcocystis hirsuta is the cat and for Sarcocystis hominis, it is the human.

Question 26

On a visit to a feedlot, the rancher asks you what method she should use to euthanize sick cattle. Which of the following is considered an acceptable method of euthanasia for conscious cattle, according to the AVMA? a. Intravenous injection of xylazine followed by intravenous injection of potassium chloride b. Air embolism (intravascular injection of air) c. Exsanguination d. Intravenous injection of bleach (sodium hypochlorite) e. Gunshot

Answer 26

e. Gunshot ## Footnote According to the AVMA Guidelines for the Euthanasia of Animals, gunshot is the most common method used for on-farm euthanasia of cattle. The anatomic landmarks used for the point of entry should be the intersection of two imaginary lines drawn from the outside corner of the eye to the center of the base of the opposite horn (or equivalent position). The person euthanizing the animal should have sufficient training and experience with the firearm for a safe and accurate procedure. Although one well-placed bullet usually results in immediate loss of consciousness with little likelihood of return to consciousness, one should always be prepared to deliver a second or even a third shot if necessary. Unacceptable methods for euthanasia of conscious animals include injection of chemical agents (disinfectants, electrolytes including potassium chloride, and nonanesthetic pharmacologic agents), drowning, air embolism, electrocution, and exsanguination. Administration of xylazine or other alpha-2 agonists followed by intravenous potassium chloride or magnesium sulfate is also considered unacceptable because alpha-2 agonists alone are recognized as being unreliable for producing generalized anesthesia although they can produce a state resembling it. Ref: AVMA Guidelines for the Euthanasia of Animals: 2013 Edition

Question 27

A dairy is having difficulties because many of the lactating cows are developing hairy foot warts as seen in the picture (papillomatous digital dermatitis) and are becoming lame. The owner plans to have all cows evaluated and the feet trimmed on those that need it. What other treatment would be effective? a. Topical daily spraying of all lesions with oxytetracycline, plus installation of properly designed and managed foot baths b. IM procaine penicillin daily for 5 days, plus properly designed and managed foot baths c. Use of a commercial Treponema vaccine in all cows d. Ceftiofur SQ for 3 days e. Commercial wart vaccine two times SQ at 4 week intervals

Answer 27

a. Topical daily spraying of all lesions with oxytetracycline, plus installation of properly designed and managed foot baths Both topical tetracycline and topical lincomycin have been found effective against the Treponema spirochete that causes this lesion. Foot baths can also be effective but difficult to manage on large dairies. A commercial vaccine is likely ineffective based on a published study finding no benefit. Systemic treatments with penicillin or ceftiofur are not recommended as effective, and penicillin use would require discarding the milk. The commercial Treponema vaccine has not been shown to be effective. Ceftiofur may not be used extra label.

Question 28

Which of the following is less likely to be elevated in white muscle disease (WMD)? a. Lactate dehydrogenase (LDH) b. Aspartate aminotransferase (AST) c. Sorbitol dehydrogenase (SDH) d. Creatine kinase (CK)

Answer 28

c. Sorbitol dehydrogenase (SDH) SDH is specific for the liver and white muscle disease involves skeletal or cardiac muscle. To review, WMD is a result of a selenium and/or vitamin E deficiency. This results in a myodegeneration of muscle which causes release of muscle enzymes into the serum. AST, CK, and LDH are all released with muscle damage.

Question 29

Guillian-Barre syndrome is an acute inflammatory demyelinating polyneuropathy of humans that has been associated with a foodborne illness. Which of the following agents has been associated with Guillian-Barre syndrome? a. Clostridium perfringens b. Campylobacter jejuni c. Listeria monocytogenes d. Yersinia enterocolitica e. Salmonella

Answer 29

b. Campylobacter jejuni Guillian-Barre syndrome appears to be an autoimmune disease that is triggered after certain respiratory and gastrointestinal infections. 40% or more cases of the syndrome are seen after Campylobacter jejuni infections. Other agents that have been associated with Guillain-Barre syndrome include cytomegalovirus and Epstein-Barr virus.

Question 30

Copper deficiency in ruminants is most often secondary and mainly associated with marginal copper levels and high levels of \_\_\_\_\_\_\_. a. Molybdenum b. Iron c. ZInc d. Cadnium

Answer 30

a. Molybdenum ## Footnote The correct answer is molybdenum. This question is sort of tricky because the other answer choices also interfere with copper absorption but to a lesser degree. Sulfates are another contributing factor.

Question 31

How many permanent teeth do cows have? a. 30 b. 44 c. 32 d. 40

Answer 31

c. 32 The correct answer is 32. There are 0/4 incisors, plus 3/3 premolars and 3/3 molars on each side. So 16 teeth per side times 2 is 32 total. The fourth incisor is actually a modified canine tooth. The same applies to both sheep and goats. Pigs have 44 permanent teeth.

Question 32

Which of the following situations is most consistent with a diagnosis of Foot-and-Mouth disease? a. Cattle are affected with oral and foot lesions and horses are unaffected b. Horses and pigs will not be affected by the disease c. Horses are affected by foot lesions while cattle are affected with oral and foot lesions d. sheep are not affected by the disease e. Both cattle and horses are equally affected with oral and foot lesions

Answer 32

a. Cattle are affected with oral and foot lesions and horses are unaffected ## Footnote The correct answer is cattle are affected with oral and foot lesions and horses are unaffected. Only cloven-hoofed animals are affected by FMD. Therefore, sheep and pigs are susceptible and horses remain unaffected. If lesions are observed in swine, it is important to differentiate FMD from swine vesicular disease. In cattle, it is important to differentiate FMD from vesicular stomatitis, bovine papular stomatitis, pseudocowpox, and bluetongue. Another point is that sheep will not be affected by vesicular stomatitis.

Question 33

This dairy cow in the picture presents for a decrease in appetite and milk production. You systematically do your physical exam and as you percuss and auscultate you hear a monotone "boink" on the left side, dorsally, approximately between rib spaces 9-13 and extending to the hip. What gas-filled organ are you hearing? a. Rumen b. Abomasum c. Cecum d. Spiral colon

Answer 33

a. Rumen The correct answer is rumen. The location extending up to the hip and the monotone "boink" (not ping) are indicative of the rumen. A cow with LDA would have a variable-pitched ping heard to only just in back of the last rib (not to the hip). It is variable because the rumen is usually still contracting medial to the displaced abomasum, and the changing gas pressures result in a pitch that changes during percussion and auscultation.

Question 34

Which two conditions may be diagnosed by finding a ping on the left side of the cow using simultaneous auscultation and percussion? a. Ruminal tympany and left displaced abomasum b. Spiral colon and torsed abomasum c. Spiral colon and cecum d. Cecum and torsed abomasum

Answer 34

a. Ruminal tympany and left displaced abomasum The correct answer is ruminal tympany and left displaced abomasum . Gas in the spiral colon, cecum, and torsion of the abomasum are diagnosed by a ping on the right side.

Question 35

What stimulus induces the release of prolactin? a. Suckling b. Grooming fetus c. Prostaglandin F2 alpha release d. Visualizing fetus

Answer 35

a. Suckling ## Footnote The correct answer is suckling. Priming a dairy cow is meant to mimic this. This form of teat stimulation causes an increase in prolactin and oxytocin which leads to milk production and let down.

Question 36

Three feedlot yearling steers in a small home ranch operation present with star-gazing, blindness, diarrhea, anisocoria, and strabismus. On physical exam, the steers are found to be underweight and in poor condition. The animals are being fed unsupplemented wheat and straw. Pupillary light response is absent in both eyes of all three. The operator reports that yesterday another steer with similar signs convulsed and died when being brought to the squeeze chute. Which of the following is the most likely diagnosis? a. Polioencephalomalacia b. Vitamin A deficiency c. Lead poisoning d. Salt poisoning

Answer 36

b. Vitamin A deficiency ## Footnote The correct answer is vitamin A deficiency. The clinical signs are very similar in these neurologic diseases. However, pupillary light reflex will stay intact with polioencephalomalacia, salt poisoning, and lead poisoning. PLRs disappear with vitamin A deficiency as a result of retinal degeneration and constriction of CN II at the level of the optic foraminae. Blood work will usually be unremarkable in these guys. CSF changes include a mononuclear cell pleocytosis of 40-50 cell/dl and increased protein of approximately 140mg/dl. It is more common for unsupplemented feedlot animals to be deficient because they do not have access to vitamin A rich, green, succulent, plants. The vitamin A requirement for most species is between 40-80 IU/kg of body weight daily.

Question 37

You are asked to examine a pen of very young dairy calves (4 to 8 weeks of age) with the complaints of aural discharges, head tilts (see image), and ataxia. You also find one with facial paralysis and another with unilateral nystagmus as you examine them. The affected ones have fevers of 103 to 105F (39.4 to 40.6 C). What organism is most likely to be causing these signs? a. Salmonella dublin b. Mycoplasma bovis c. Histophilus somni d. E. coli e. Mannheimia hemolytica

Answer 37

b. Mycoplasma bovis M. bovis may be spread to young calves via milk. In very young dairy calves it can cause otitis media with aural discharge, head tilt, nystagmus, ataxia, and even facial nerve paralysis. It also causes respiratory disease and can cause arthritis and tenosynovitis in older calves. Mastitis, abortion and other signs can also be caused by M. bovis.

Question 38

A 2 year old Holstein dairy cow presents for lethargy, anorexia, and decreased production. On physical exam, the cow has a temperature of 104.5F (40.3 C), a respiratory rate of 68 bpm, a heart rate of 90 bpm, muffled heart sounds that have a distinct washing machine sound of splashing and dripping, heard best on the left side. The jugular veins are prominent. What is your tentative diagnosis? a. Advanced traumatic reticulopericarditis b. Heart base lymphoma caused by bovine leukosis virus c. Ventricular septal defect d. Endocarditis of the tricuspid valve

Answer 38

a. Advanced traumatic reticulopericarditis The murmur results from development of pericarditis and may be described as a washing machine murmur. It results when there is a fluid-gas interface in the pericardial sac. The heart sounds are muffled because of the thickened and fluid filled pericardial sac. Tricuspid endocarditis would result in a loud right sided murmur. A ventricular septal defect would have a loud systolic or constant murmur heard on either side. A heart base tumor could cause muffled heart sounds but would not have the washing machine sounds and would be unlikely in a 2 year old cow (usually BLV lesions occur in older cattle).

Question 39

Animals tend to have about 2/3 of their body weight made up of water. For total body water, what is the ratio of ECF to ICF (extracellular fluid to intracellular fluid)? a. 1:3 b. 3:1 c. 2:1 d. 1:1 e. 1:2

Answer 39

e. 1:2 If a cow weighs 450 kg, she will have about 300 liters of body water. Of this, about 100 liters is ECF and 200 liters is ICF.

Question 40

All of the following are contagious mastitis pathogens of cows except for \_\_\_\_\_\_\_\_\_\_\_\_. a. Staphylococcus aureus b. Streptococcus agalactiae c. Mycoplasma d. E. coli

Answer 40

d. E. coli ## Footnote The correct answer is E. coli. This pathogen is an environmental pathogen.

Question 41

A local purebred cattle herd has been increasingly affected with papillomas to the point that it is now a problem throughout the herd, and the owner is concerned. Which of the following treatment options would yield the best results? a. Purchase commercially available vaccine b. Depopulate the herd c. Treat herd with acylovir d. Prepare an autogenous vaccine by isolating some warts from the herd

Answer 41

d. Prepare an autogenous vaccine by isolating some warts from the herd The correct answer is to prepare an autogenous vaccine by isolating some warts from the herd. The commercially available vaccine is thought to be effective only against the same strain; therefore, it is not curative in many cases. Treating with acyclovir is not recommended. The least desirable treatment option would be depopulation of the herd. This would potentially be financially devastating.

Question 42

In cattle, pododermatitis circumscripta involves a lesion at the \_\_\_\_\_\_\_\_\_\_. a. Sole/bulb junction b. Hoof wall-white line junction c. Coronary band-hoof wall junction d. Interdigital region-coronary band junction

Answer 42

a. Sole/bulb junction Usually the weight-bearing claws are affected first (lateral digits in the hind and medial digits in the front).

Question 43

This 3-year old Charolais cow in the picture presents with a 2-day history of not eating and looking uncomfortable and hunched up. There are no others in the herd affected. On physical exam, there is decreased rumen motility, a temperature of 105.2F or 40.7C, and a heart rate of 82 bpm. You perform a scooch test on the cow by firmly squeezing down over the withers. The test was positive (she refused to dip her back normally). What is your most likely diagnosis? a. Bovine spongiform encephalopathy b. Grain overload c. Traumatic reticuloperitonitis d. Left displaced abomasum

Answer 43

c. Traumatic reticuloperitonitis ## Footnote This question provided a classic description of the presentation for TRP. The clinical signs can be vague and misleading, but the localization of xiphoid pain as shown with the scooch test is a strong indicator of TRP. With a positive scooch test, the cow will be stiff, reluctant to scooch down, and grunts may be heard. Sometimes the stethoscope needs to be placed over the trachea because the grunt may be soft. Additionally, the xiphoid region should be pushed up upon to see whether the cow reacts painfully. There is no mention of pinging that would indicate a displaced abomasum. Xiphoid pain would not be seen as a result of grain overload. Cows with bovine spongiform encephalopathy (mad cow disease) will show neurologic clinical signs such as hypermetric ataxia, hyperexcitability, and hyperesthesia.

Question 44

Infectious bovine rhinotracheitis ophthalmic lesions are caused by which virus? a. Bovine Herpes virus II b. Bovine Herpes virus I c. Bovine Lenti virus d. Bovine Herpes virus III

Answer 44

b. Bovine Herpes virus I The correct answer is bovine herpes virus I. The virus infects the trigeminal ganglia and becomes latent. When an animal is immunosuppressed, the virus replicates and causes disease. Herpes II causes bovine ulcerative mammilitis. Herpes III is the alcelaphine herpes virus (African malignant catarrhal fever). Lenti virus in cattle causes bovine leukosis.

Question 45

The owner of a new beef ranch on poor volcanic soil asks you to evaluate 2 steers. They are representative of an ongoing herd problem of chronic diarrhea and respiratory disease that is unresponsive to antibiotic treatment. On physical exam, you notice achromotrichia, ill thrift, and a temperature of 103F (39.4 C) in both steers. You perform a transtracheal wash in one of the steers and it comes back positive for Pasteurella multocida. What is your diagnosis? a. Copper deficiency b. Bovine viral diarrhea c. Selenium deficiency d. Pasteurella pneumonia

Answer 45

a. Copper deficiency The giveaway is achromotrichia or loss of hair color. Dilution of the coat color is due to dysfunction of tyrosinase which converts L-tyrosine to melanin. In addition, copper deficient animals will have spontaneous fractures, secondary respiratory disease, diarrhea, ill thrift, decreased immunity, anemia, and poor reproduction. Selenium deficiency and BVD are actually pretty good differentials and if achromotrichia was not present either of those two are reasonable choices. Molybdenum deficiency would not result in achromotrichia. On the other hand, if there had been excess molybdenum, then the Cu:Mo ratio would be off and copper deficiency could be observed.

Question 46

Which organism is most commonly isolated in pituitary abscesses of ruminants? a. Streptococcus zooepidemicus b. Staphylococcus c. Fusobacterium necrophorum d. Pasteurella hemolytica e. Arcanobacterium pyogenes

Answer 46

e. Arcanobacterium pyogenes The correct answer is Arcanobacterium pyogenes, formerly called Actinomyces pyogenes. Pituitary abscesses are not too common in ruminants and this is a pretty random question. But if you see this on boards you will be the bomb! Actinomyces pyogenes is also a common cause of brain abscesses.

Question 47

What is the cause of alpha-Mannosidosis? a. Genetic b. Bacterial infiltration of the gyri c. Viral d. Fungal

Answer 47

a. Genetic The correct answer is genetic (autosomal-recessive). The condition is the result of a defect of the enzyme alpha-mannosidase and is seen in Murray gray, Simmental, Holstein, Galloway, and Angus cattle. The cleavage between N-acetyl glucosamine and mannose will not occur and the oligosaccharide will accumulate within the lysosomes of neurons, reticuloendothelial cells, and macrophages. The first sign at 1 month to 15 months of age will be a mild ataxia of the pelvic limbs after exercise. Other signs then develop, including hypermetria, aggressiveness, and intention head tremors. Most affected individuals will end up getting diarrhea and becoming recumbent and die within months after diagnosis.

Question 48

This is not a clinical sign of Horner's syndrome in cattle. a. Enophthalmos b. Miosis c. Mydriasis d. Ptosis

Answer 48

c. Mydriasis ## Footnote The correct answer is mydriasis. Horner's syndrome causes miosis (constriction of the pupil), enophthalmos, ptosis, regional hyperthermia, and congested mucous membranes. Horner`s is a result of disruption of ocular sympathetic pathways.

Question 49

A rancher who lives at 8000 ft. elevation in Colorado is planning to buy good bulls and wants you to test them for susceptibility to high mountain disease (pulmonary hypertension and cor pulmonale). See image for what high mountain disease looks like. You recommend doing pulmonary artery pressure (PAP) testing in the squeeze chute to measure their susceptibility to pulmonary hypertension. Which of the following PAP measurements, taken at 6000 ft. elevation, would be satisfactory for this ranch to purchase? a. None, the testing must be done below 5,000ft. elevation to be reliable b. None, there is no reliable way to predict susceptibility to high mountain disease c. 55 to 60 mmHg pressure d. 45 to 50 mmHg pressure e. Less than 40 mmHg pressure

Answer 49

e. Less than 40 mmHg pressure ## Footnote PAP testing done at elevations 6000 ft. or above on animals over 12 months of age is a reliable predictor of genetic susceptibility to high mountain disease (the BMPR2 gene is involved). The lowest pulmonary artery pressure readings are the least susceptible animals. Using local anesthesia, a catheter is inserted into the jugular vein and threaded into the right heart and pulmonary artery where the pressure is taken while the animal is restrained in a squeeze chute. The condition is caused by a genetic predisposition to developing pulmonary hypertension when oxygen tension is reduced. The pulmonary hypertension leads to pulmonary artery hypertrophy, cor pulmonale, and right heart failure. The hallmarks are lethargy, distended jugular vein, and ventral edema (see image), as well as diarrhea, pulmonary edema, and pleural effusion. Ingestion of toxic plants such as locoweed worsen the disease by causing additional pathology. Cold weather, pregnancy and other stresses can also predispose animals and cause borderline susceptible animals to develop the condition.

Question 50

A cow presents due to a decrease in milk production. On physical exam, you were unable to hear the heart clearly (it is muffled). You decide to perform an ECG and immediately recognize that this cow has electrical alternans. What is most likely to be occurring? a. Pericardial effusion b. Left ventricular enlargement c. Right atrial enlargement d. Left atrial enlargement e. Right ventricular enlargement

Answer 50

a. Pericardial effusion ## Footnote The correct answer is pericardial effusion. Electrical alternans is a classic finding in cases where there is pericardial effusion. Electrical alternans is characterized by different amplitudes of multiple successive R waves in the QRS complex. This is thought to be a result of the heart shifting around within the fluid filled compartment of the pericardial sac.

Question 51

In performing ocular ablation (removal) to treat severe cancer eye in a commercial beef cow, which of the following is the most appropriate anesthesia to use in the field? a. A five point orbital block using lidocaine b. General anesthesia using sodium pentathol (barbiturate) c. General anesthesia using fluothane intubation following intramuscular xylazine d. Sedation using xylazine and testraint in a squeeze shute e. Topical anesthesia using proparacaine or tetracaine

Answer 51

a. A five point orbital block using lidocaine Squamous cell carcinoma is by far the most common ocular tumor in cattle and is referred to as "cancer eye". Treatment can vary from resection of part of an eyelid to complete enucleation including the eyelids. Recurrence is common, as spread to the lymph node can occur if not caught early on. The cow should be restrained in a squeeze chute and the head tied to one side so that the abnormal eye is accessible. The area should be closely clipped or shaved and disinfected, then generous amounts (10 ml per site, 50 ml total) of local anesthetic are injected using a 19 ga 2.5 inch (6 cm) needle. The 5 injection sites include the medial canthus, and then twice through each lid so that the tissues around the globe are flooded with local. Alternatively the Peterson`s orbital nerve block (another local block) can be utilized.

Question 52

A 3-year old fresh cow presents to your clinic for lameness. You immediately notice her forelimbs have long hoof walls with rings and an abnormal appearing wall horn. What is this condition associated with? a. Chronic mastitis b. Chronic respiratory disease c. Chronic interdigital necrobacillosis d. Chronic laminitis e. Chronic alkalosis

Answer 52

d. Chronic laminitis ## Footnote The correct answer is chronic laminitis. When you see slipper feet, both claws are overgrown and appear to have abnormal hoof wall growth. Laminitis in cattle is almost always caused by rumen acidosis.

Question 53

You arrive at a beef ranch in a mountain meadow at 5000 feet elevation in the western US because the owner has called with the complaint of sudden death losses in adult cows, and another one staggering. You examine the sick animal and find fever of 105F (40.6 C), elevated respiratory rate, HR of 100/min, icteric mucous membranes, and weakness. You collect a urine sample and it appears dark red (see image). You also perform a post-mortem on one of the recently dead cows and find a hepatic infarct, icteric tissues and hemoglobinuria. The owner asks for a diagnosis, treatment, and prevention. a. Acute Fasciola hepatic infestation; penicillin, fluke control b. Lightning strike; provide shelters with lightning rods c. Blackleg; penicillin, vaccination d. Blue-green algae toxicity; no treatment, prevent via clean water source e. Bacillary hemoglobinuria; penicillin, vaccination, and fluke control

Answer 53

e. Bacillary hemoglobinuria; penicillin, vaccination, and fluke control The diagnosis is bacillary hemoglobinuria caused by Clostridium novyi type D (formerly called Cl. hemolyticum). Penicillin can be given to any animal showing early signs. Vaccination with Cl. novyi type D vaccine is effective, and prevention should also include fluke control. Migrating flukes cause hepatic damage and anaerobic areas which results in germination of the Cl. novyi spores in the liver, an infarct, and production of the hemotoxin. Flukes are best controlled by controlling snails in wet areas, fencing off wet areas, and using routine fluke treatments.

Question 54

Preventing transmission and the effects of flukes such as Fasciola hepatica on cattle in the southern United States where it is wet and warm in spring and summer depends on several factors, such as keeping cattle out of marsh areas where snails exist. What other major intervention would best help control the number of flukes in cattle? a. Treating all cattle which show clinical signs of heavy fluke infestation b. Vaccinating against Clostridium hemolyticum (redwater) c. Optimal preventive treatment 2 to 3 months after major transmission season d. Running periodic fecal sedimentation tests for fluke eggs and treating when numbersgo up

Answer 54

c. Optimal preventive treatment 2 to 3 months after major transmission season ## Footnote The major transmission season differs by geographic area, being later in the north and also affected by irrigation of pasture in the west. Treating with a flukecide 2 to 3 months after major transmission season is effective at controlling flukes in most herds, but in some herds a second treatment to remove flukes acquired late in the season (such as on irrigated pasture) may be necessary. Vaccinating against Clostridium hemolyticum is also a good idea but will not control the fluke numbers.

Question 55

A group of 30 housed 4-6 month-old Friesian heifer calves presents with multifocal several-centimeter skin lesions like the ones seen in the image. The lesions are primarily located around the head and neck but are also seen more sparsely in other areas. The lesions are superficial, dry, scaly and do not appear pruritic. The underlying skin is not thickened. The cows are eating and behaving otherwise normally. Which of the following tests will help confirm your presumptive diagnosis? a. Measure serum and liver copper levels b. Bacterial culture of the most severe lesions c. Microscopic examination of a hair/skin scraping from edge of the lesions d. Measure serum zinc levels e. Genetic testing

Answer 55

c. Microscopic examination of a hair/skin scraping from edge of the lesions ## Footnote You should be most suspicious of ringworm based on the lesion appearance and distribution. Microscopic examination from the periphery of the lesions is likely to reveal fungal hyphae of Trichophyton spp. Dermatophyte culture would also be a good option. Ringworm will typically regress over many months without treatment but untreated lesions may present risk of transmission including zoonotic transmission. Topical treatments including 4% lime sulfur, 0.5% sodium hypochlorite (1:10 household bleach), 0.5% chlorhexidine, 1% povidone-iodine, natamycin, and enilconazole may be options and likely work best if any crusts are removed prior to application.

Question 56

At what age during gestation is a fetus most likely to become persistently infected with the noncytopathic form of bovine viral diarrhea? a. Fetus infected between 200-270 days of gestation b. Fetus infected before 125 days of gestation c. Fetus infected between 150-200 days of gestation d. Fetus infected at 320 days of gestation

Answer 56

b. Fetus infected before 125 days of gestation The correct answer is fetus infected before 125 days of gestation, with most of those occurring before 100 days. A fetus infected with BVD at any time during gestation can be aborted or be a stillbirth. Most congenital defects associated with BVD occur when a fetus is infected between days 90-150 of gestation. Persistent infection of fetuses is seen when they are infected before 125 days of gestation. This is of importance because they have a potential to affect many other herdmates since they shed virus but may show no clinical signs. About half of the persistently infected calves will die during their first year of life. Clinical signs in BVD carriers vary greatly. They may range from an asymptomatic animal to one that has diarrhea, fever, pneumonia, and oral ulcerations. Additionally, you may have infected animals that are just repeat breeders. You may also see abortions, stillbirth, and congenital anomalies. The most common congenital anomaly associated with BVD is cerebellar hypoplasia, but there are many others.

Question 57

What is the treatment for tuberculosis in cattle? a. Pyrazinamide b. Cull/slaughter c. Isoniazid d. Amikacin

Answer 57

b. Cull/slaughter The correct answer is cull. This is a result of the severe zoonotic potential at hand. All cattle suspected of having tuberculosis must be reported to state and federal officials.

Question 58

What is the common lung worm of cattle? a. Dictyocaulus filaria b. Pneumonyssus c. Muellerius capillaris d. Dictyocaulus viviparous e. Trichophyton verrucosum

Answer 58

d. Dictyocaulus viviparous ## Footnote The correct answer is Dictyocaulus viviparous. Dictyocaulus filaria affects small ruminants more commonly. Muellerius capillaris can affect sheep and goats, but it is rare since the animals have to ingest large numbers of snails to become infected. Pneumonyssus is a nasal mite that usually affects dogs. Trichophyton verrucosum is the most common cause of ring worm in cattle.

Question 59

Which organism is most commonly isolated in pituitary abscesses of ruminants? a. Pasteurella hemolytica b. Streptococcus zooepidemicus c. Staphylococcus d. Fusobacterium necrophorum e. Arcanobacterium pyogenes

Answer 59

e. Arcanobacterium pyogenes The correct answer is Arcanobacterium pyogenes, formerly called Actinomyces pyogenes. Pituitary abscesses are not too common in ruminants and this is a pretty random question. But if you see this on boards you will be the bomb! Actinomyces pyogenes is also a common cause of brain abscesses.

Question 60

A 4 month old Holstein calf presents with a right sided head tilt, a unilateral right ear droop, right eye ptosis and epiphora of the right eye. Otherwise, the calf is bright and alert. The owner mentioned that the calf suffered from a respiratory infection the previous week. What is the most likely diagnosis? a. Polioencephalomalacia b. Otobius megnini c. Congenital brain tumor d. Otitis media-externa

Answer 60

d. Otitis media-externa Mycoplasma is a common cause of otitis media-externa. Usually, the infection is a result of consuming contaminated milk. A congenital brain tumor is highly unlikely. Otobius (soft tick with predilection for ears) is unlikely because the clinical signs are not consistent; however, it is a good differential. With Otobius the calf would probably not show such extreme clinical signs and would probably be scratching and rubbing at the ear. Polioencephalomalacia is more likely to present with stargazing, head pressing, depression, and blindness. Polioencephalomalacia is caused by a thiamine deficiency. An excellent differential for the clinical signs described would be listeriosis and thromboembolic meningoencephalitis.

Question 61

You are presented with a 10-day old dairy calf that is cold (Temperature is 97 degrees F, 36.1 degrees C) and nonresponsive. His eyes appear sunken as in the photo. In addition to placing the calf on a warming pad, what is the best treatment? a. 1 liter of subcutaneous fluids containing glucose, sodium, bicarbonate, chloride and lesser amounts of potassium b. 4 liters of intravenous fluids containing glucose, sodium, bicarbonate, chloride and lesser amounts of potassium c. Gentamicin intravenously at the label dosage d. 4 liters alkalizing fluid containing equal amounts of sodium and chloride

Answer 61

b. 4 liters of intravenous fluids containing glucose, sodium, bicarbonate, chloride and lesser amounts of potassium ## Footnote The calf is in metabolic acidosis (base deficit of about 15) and needs sodium containing fluids IV that contain bicarbonate or other base. 4 liters intravenously is a more appropriate fluid volume for a dehydrated 10-day old calf , calculated as 10% 0f the 40 kg body weight. The sunken eye, as seen in the photo, is an important indicator of marked dehydration. To treat metabolic acidosis caused by loss of sodium containing fluids you need to give more sodium than chloride, so sodium bicarbonate is the fluid of choice. The calf is also likely to be hypoglycemic, so adding glucose is essential. As you rehydrate and bring up blood glucose, the serum potassium will be driven back into cells and needs to be replaced with some potassium in the fluids.

Question 62

Which of the following is not a likely outcome in a cattle herd with a Mycoplasma infection? a. Cystitis b. Mastitis c. Keratoconjunctivitis d. Otitis media e. Infectious arthritis

Answer 62

a. Cystitis ## Footnote The correct answer is cystitis. Additionally, Mycoplasma can cause reproductive and joint disease.

Question 63

Which of the following standing laparotomy approaches in a cow would correctly be done only from the right flank? a. Cecal volvulus b. Traumatic reticuloperitonitis c. Grain overload (to empty the rumen) d. Left displaced abomasum e. Caesarean section

Answer 63

a. Cecal volvulus ## Footnote Only the cecum is only approached on the right side, as opposed to the left flank. LDA and C-section could be done from either side.

Question 64

What is the growth medium of choice for Mycoplasma bovis? a. Chocolate agar b. Hayflick's agar c. MacConkey agar d. Blood agar

Answer 64

b. Hayflick's agar ## Footnote The correct answer is Hayflick's agar. Mycoplasma bovis does not grow well on the other choices provided. Additionally, you will want to grow it in a microaerophilic environment.

Question 65

You are presented a dead 4-month old dairy heifer for postmortem exam with a history of lameness and fevers in the group. The owner tells you that several other animals are affected, with more appearing every day. You find pneumonia (ventral yellow firm nodules in a consolidated lung) and polyarthritis (see image) as well as tenosynovitis. What organism is most likely to be the cause of such an outbreak? a. Pasterurella hemolytica b. Histophilus somnus c. Mannheimia hemolytica d. Mycoplasma bovis e. Mycoplasma agalactiae

Answer 65

d. Mycoplasma bovis ## Footnote In young calves M. bovis can cause head tilt, aural discharges, facial paralysis, ataxia, and nystagmus as ear infections occur. In older cows it can cause pneumonia, with or without the arthritis and tenosynovitis. It can also cause mastitis, abortion and other disorders.

Question 66

How many permanent teeth do cows have? a. 32 b. 40 c. 30 d. 44

Answer 66

a. 32 ## Footnote The correct answer is 32. There are 0/4 incisors, plus 3/3 premolars and 3/3 molars on each side. So 16 teeth per side times 2 is 32 total. The fourth incisor is actually a modified canine tooth. The same applies to both sheep and goats. Pigs have 44 permanent teeth.

Question 67

It is summer in the hills of coastal California. During spring and early summer, cattle in the area were eating the plant shown in the photo, before other forage was available. Which of the following disorders might occur in cattle which ate a large amount of the plant shown? a. Bone marrow suppression b. Liver failure c. CNS signs d. Cardiac arrhythmia e. Cyanide toxicosis

Answer 67

a. Bone marrow suppression ## Footnote The plant is bracken fern and it contains a toxic glycoside (ptaquiloside) plus thiaminase. In cattle, chronic bracken fern ingestion (consumption of the animal's body weight over several months) can result in bone marrow suppression, as well as alkylation of DNA leading to tumors. The problem will manifest as hemorrhages, hematuria, and/or cancers in the bladder or other organs. The bone marrow suppression leads to anemia and neutropenia. The thiaminase seems to affect horses more than cattle. Horses develop thiamine deficiency manifested as weight loss, ataxia, lethargy, tremors, recumbency, and death.

Question 68

An 8 week old Beefmaster calf presents with a 2 day history of rapid and labored respiration, depression, salivation, nasal and ocular discharge, and a "honking" cough. On physical exam, there are no signs of sepsis, but the calf is tachypneic, dyspneic and febrile. Crackles are audible throughout the lung fields. What is your top differential? a. Pasteurella multocida b. Mannheimia hemolytica c. Bovine respiratory syncytial virus d. Haemophilus pleuropneumoniae

Answer 68

c. Bovine respiratory syncytial virus ## Footnote The correct answer is bovine respiratory syncytial virus. The key to being able to make this your top differential is noting that the calf has a "honking" cough, dyspnea, and tachypnea, that the calf is not septic. Pulmonary lesions include severe edema and emphysema. Treatment is usually supportive and antibiotics are given to protect from secondary bacterial infection. Mannheimia hemolytica is the main culprit in shipping fever, and Haemophilus pleuropneumoniae is an occasional cause of shipping fever in cattle. Pasteurella multocida can be a secondary invader in any bovine pneumonia. P multocida also causes the most economic loss in swine with atrophic rhinitis.

Question 69

A 2 year old dairy heifer presents with a stiff walk and arched back. On physical exam, the heifer has fever of 104F, a "washing machine" murmur, distended jugular veins, and a positive grunt test (pain when you apply upward pressure in the xiphoid region). What is the most likely diagnosis? a. Traumatic reticulopericarditis b. Ventricular septal defect c. Endocarditis d. Cor Pulmonale

Answer 69

a. Traumatic reticulopericarditis ## Footnote The correct answer is traumatic reticulopericarditis. This is a classic presentation. The washing machine murmur is due to the presence of both fluid and gas in the pericardium resulting in splashing and dripping sounds. Right heart failure is usually a component of traumatic reticulopericarditis. You will see a jugular pulse, distended jugular veins, and brisket edema with right heart failure. The prognosis is poor. Prevention is best achieved by giving all cows over 500lbs a magnet and keeping them away from wires (using string baling twine)and other metallic objects that could be ingested.

Question 70

A 4 year-old dairy cow that is 2 weeks post-partum is experiencing low milk production and appears to not be eating well, spending less time at the feed bunk than herd mates. She has also been heard grinding her teeth, swishing her tail, and repeatedly lying down and getting up after a short time. You examine her and find a fever of 105F (40.6 C), HR=90/min, rumen quite empty, rumen motility poor, and a gaunt abdomen. On rectal exam the left kidney appears to be enlarged and painful; no other abnormalities are noted. You take a urine sample and note blood and pus in it. What is the most likely diagnosis? a. Metritis b. Urolithiasis c. Glomerulonephritis d. Renal tumor e. Pyelonephritis

Answer 70

e. Pyelonephritis Pyelonephritis occurs most commonly in post-partum cows when bacteria enter via the urethra due to a post-partum uterine infection and vaginal damage at calving. The most common organisms found are coliforms or Corynebacterium renale. The resultant ascending infection causes renal swelling and pain (grinding teeth, swishing tail, repeatedly up and down), fever, and loss of appetite. Urolithiasis is rare in dairy cows and urolithiasis in female ruminants is rarely symptomatic, as the stones usually pass readily. Glomerulonephritis would not be so painful and would not result in blood and pus in the urine. Metritis could result in seeing pus and blood in a free catch urine sample, but the cow is unlikely to be colicky with metritis, and 2 weeks post-partum is a long delay in acute metritis (usually occurs a few days post-partum).

Question 71

You are presented with a Holstein bull because he is not eating well. He has a normal temperature, HR=80 and RR=20. There is ventral abdominal edema (see image) and his breath smells like ammonia. Ultrasonography of the abdomen reveals free abdominal fluid and a collapsed urinary bladder. You suspect a ruptured bladder and urethra with secondary uroperitoneum due to a urolith in the urethra. Which of the following test results on blood are most useful in confirming your diagnosis? a. Hyponatremia, hypokalemia, hyperchloremia b. Hypernatremia, hyperchloremia, hyperkalemia c. Hyponatremia, hypochloremia, hyperphosphatemia d. Azotemia, hypohosphatemia, hypernatremia

Answer 71

c. Hyponatremia, hypochloremia, hyperphosphatemia ## Footnote These are the electrolyte abnormalities that should be expected in cases of uroabdomen. There would also be azotemia (elevated urea nitrogen), and possibly hyperkalemia in the blood.

Question 72

A feedlot operator calls you to perform a postmortem exam on a dead 5-month old calf that was in his feedlot for 3 weeks before it developed diarrhea and died quickly. On postmortem, you find some erosions of the dental pad, ileitis, and a severely ulcerated esophagus (see image). Based on the history and postmortem findings, which of the following is the most likely cause of death in this calf? a. Bluetongue virus b. Malignant catarrhal fever c. Bovine papular stomatitis d. Salmonella typhimurium e. Mucosal disease

Answer 72

e. Mucosal disease MD is the severe form of BVD, believed to occur chiefly when an animal born infected with the non-CPE (non cytopathic effect) form of BVD virus is superinfected with CPE biotype of BVD virus, or the virus transforms to the CPE biotype. Severe ulcerations throughout the GI tract can result in death.

Question 73

A three-year old Jersey cow presents for decreased milk production and weight loss. On physical exam, a hard, non-painful swelling of the mandible is identified. Radiographs of this region show lysis and productive bone lesions, with distortion of the teeth in the area. What is the most likely cause for these findings? a. Actinomycosis b. Actinobacillus lignieresii c. Osteosarcoma d. Vesicular stomatitis

Answer 73

a. Actinomycosis ## Footnote This cow has become infected with Actinomyces bovis (lumpy jaw) as a result of sustaining an injury in the mucous membranes, often from eating hard scabrous feeds. Actinomyces bovis is part of the normal oral and rumen flora and can become a source of infection when cows consume items that traumatize their mouths. The lesion classically causes a hard non-painful swelling of the mandible or maxilla along with productive and destructive bony changes. Teeth may be lost. Osteosarcoma is very uncommon in cattle and is therefore a poor answer choice. Vesicular stomatitis will not cause a hard non-painful swelling. Instead, you may see oral ulceration as a result of ruptured vesicles along the tongue. This virus can also cause lesions of the feet and teats. Cows infected with vesicular stomatitis will most likely be salivating, not eating, depressed, and febrile. Actinobacillus lignieresii is the causative agent of woody tongue. In this case, you would expect to see a large firm tongue on physical exam. Sodium iodide has been used to treat lumpy jaw, but this will only arrest the lesion.

Question 74

A beef cow presents with blepharospasm and chemosis. You perform a fluorescein stain and see a centrally located ulceration of the cornea. Which is NOT a treatment option? a. Penicillin G subconjunctivally b. Florfenicol c. Long-acting oxytetracycline IM or IV d. Chloramphenicol

Answer 74

d. Chloramphenicol ## Footnote Chloramphenicol is NOT a treatment option. This drug is not labeled for use in food animals and is prohibited for food animals in the USA, with the possibility penalty of losing one's license. Benign neglect is not an incorrect answer because these ulcers usually heal with time. The only down side is all the morbidity you will get for not treating. Further, these are classical clinical signs for infectious bovine keratoconjunctivitis, most commonly caused by Moraxella bovis, which is most common in calves.

Question 75

While performing physical exams at a state fair, you notice one of the cows has a central ulcer in her eye as shown in this image. What is your diagnosis? a. Thelazia b. Pinkeye c. Infectious bovine rhinotracheitis d. Bovine viral diarrhea

Answer 75

b. Pinkeye ## Footnote The correct answer is pinkeye (infectious bovine keratoconjunctivitis). This image is a typical representation of what you are likely to observe. Usually, initial symptoms are blepharospasm, chemosis, and photophobia. This is due to the centrally located ulcer from the infection. The ulcer usually runs its course over a few weeks, however sometimes you may observe corneal descemetoceles and corneal perforation. Therefore, you will probably want to treat these conditions also. Additionally, it is very painful and stressful for the animals, and they will decrease their productivity. IBR and Thelazia (eyeworm) can also cause ocular signs.

Question 76

Which virus can result in congenital microphthalmia in calves? a. Infectious bovine rhinotracheitis b. Bovine viral diarrhea c. Foot-and-mouth disease d. Malignant catarrhal fever

Answer 76

b. Bovine viral diarrhea ## Footnote The correct answer is bovine viral diarrhea. Calves born with BVD are persistently infected and should be culled.

Question 77

A herd of cattle present for an acute onset of a mild cough. Many of the cattle subsequently die and the others have improved over the course of several days. The cattle had a history of being moved to a lush pasture. Necropsy findings showed acute interstitial pneumonia and air filled bullae. What is the likely chemical responsible for this disease? a. Methylmethacrylate b. Magnesium c. 3-Methylindole d. 4-Ipomeanol

Answer 77

c. 3-Methylindole The correct answer is 3-methylindole. Cattle that are moved to lush forage that is high in tryptophan metabolize the tryptophan to 3-methylindole in the rumen. The 3-MI is toxic to the lung, resulting in acute interstitial pneumonia and emphysema. This syndrome is known as acute bovine pulmonary edema and emphysema (ABPEE), fog fever or grunts. 4-Ipomeanol is the chemical involved in moldy sweet potato poisoning, which looks clinically similar to this.

Question 78

Louse infestations in cattle sometimes require veterinary intervention. Which of the following statements is false? a. Mallophaga are biting lice b. Adult lice have 8 legs c. Anoplura are sucking lice d. Lice are usually species-specific

Answer 78

b. Adult lice have 8 legs The false statement is adult lice have eight legs. Adult lice have 6 beautiful little legs. The other statements are true. Remember that Anoplura lice can cause anemia if their numbers are sufficient

Question 79

Which of the following is approved for use in food animals in the USA? a. Clenbuterol b. Chloramphenicol c. Ceftifur d. Dimetridazole

Answer 79

c. Ceftifur ## Footnote The correct answer is ceftiofur, which is a thrid generation cephalosporin approved for treating acute respiratory disease in cattle. Extra label use is now prohibited. Many of you may know this drug as Naxcel. All others listed are illegal for use in food animals in the USA.

Question 80

What is the effect of PGF2-alpha during anestrus in cattle? a. Induces an LH surge b. Causes the lysis of the corpus luteum c. Induces FSH release d. There is no effect

Answer 80

d. There is no effect ## Footnote The correct answer is that there is no effect when the cow is in anestrus. That is the problem with using PGF2-alpha to synchronize estrus cycles in cows. A mature corpus luteum is needed so that PGF2-alpha can lyse it; the cow goes back into estrus in about 2-5 days.

Question 81

You examine a valuable 4-year old black and white Holstein dairy cow in mid-lactation with the complaint of poor appetite and a sudden decrease in milk production. T=105F (40.6 C), HR=105, RR=30. The heart is muffled and difficult to auscult, and there is a moderate amount of brisket edema present. Rumen motility is poor, but no other abnormalities are noted on abdominal and rectal exams. Of the following which is the most likely cause of her drop in milk production? a. Valvular endocarditis b. Traumatic pericarditis c. Cardiomyopathy d. Brisket disease e. Ventricular spetal defect

Answer 81

b. Traumatic pericarditis If a metallic foreign body penetrates the reticulum and the pericardium, the resulting infection will lead to large amounts of infected pericardial fluid, which in turn causes constrictive heart disease and heart failure. Some people refer to this condition as Hardware disease or traumatic reticuloperitonitis. A muffled heart sound along with brisket edema should increase your suspicion for this disease. A ventricular septal defect or valvular endocarditis will likely not result in muffled heart sounds. Cardiomyopathy would not be expected to cause a fever or muffled heart. Brisket disease occurs as a result of lack of oxygen at high altitude. As the syndrome progresses, subacute edema develops in the brisket region. Marked distention and pulsation of the jugular veins are usually present.

Question 82

What valve is most commonly affected with endocarditis in cattle? a. Pulmonic b. Tricuspid c. Mitral d. Aortic

Answer 82

b. Tricuspid The vast majority of endocarditis cases in cattle involve the tricuspid valve. This is in contrast to small animals and horses where the aortic valve is most commonly affected. Remember, with endocarditis, the animal may be septic as well and have swollen joints. Common causes of endocarditis in cattle are foot abscesses and other sites where pus and blood mix.

Question 83

A 3-year old Jersey heifer is not doing well and is euthanized with a post-mortem performed in the field. Below is an image of her heart, with the right atrium and right ventricle opened. What is your diagnosis? a. Tricuspid valve dysplasia b. Tricuspid valve endocarditis c. Cardiac neoplasia d. No significant findings e. Ventricular septal defect

Answer 83

b. Tricuspid valve endocarditis The correct answer is tricuspid valve endocarditis. Hemorrhagic and white masses are seen on all leaflets of the tricuspid valve which makes endocarditis the most likely diagnosis in a young heifer. Neoplasia is unlikely on the valve and at this age; tricuspid valve dysplasia would be seen as short, thick chordae but no masses; a VSD would be seen as a hole between the right and left ventricle which is not apparent here.

Question 84

A valuable 14-day old Holstein dairy calf has had diarrhea and the owner has treated it for several days with oral electrolytes and withheld milk. Today it has some CNS signs, and you have been asked to examine and treat the calf. You take a serum sample and measure electrolytes, finding the serum sodium at 180 mEq/L (136-144 mEq/L). What should you now do for treatment? a. Give diuretics to drive out the sodium b. Offer small amounts of milk to the calf d. Allow the calf access to free water and let it drink e. Slowly correct the sodium using IV fluids e. Give the calf 100mL 7% hypertonic saline IV

Answer 84

e. Slowly correct the sodium using IV fluids Start with a slightly hypertonic IV fluid with a sodium level of 160-170 meq/L and slowly correct the sodium over several days, gradually moving to normal sodium containing fluids like Ringers. Start on milk and offer oral water only after the correction is well under way. With this history, it is highly likely that the calf's brain sodium is also 180 meq/L; if given too much free water too rapidly, the water will enter the brain and cause swelling and death.

Question 85

A 4 year-old dairy cow that is 2 weeks post-partum is experiencing low milk production and appears to not be eating well, spending less time at the feed bunk than herd mates. She has also been heard grinding her teeth, swishing her tail, and repeatedly lying down and getting up after a short time. You examine her and find a fever of 105F (40.6 C), HR=90/min, rumen quite empty, rumen motility poor, and a gaunt abdomen. On rectal exam the left kidney appears to be enlarged and painful; no other abnormalities are noted. You take a urine sample and note blood and pus in it. What is the most likely diagnosis? a. Renal tumor b. Urolithiasis c. Metritis d. Pyelonephritis e. Glomerulonephritis

Answer 85

d. Pyelonephritis ## Footnote Pyelonephritis occurs most commonly in post-partum cows when bacteria enter via the urethra due to a post-partum uterine infection and vaginal damage at calving. The most common organisms found are coliforms or Corynebacterium renale. The resultant ascending infection causes renal swelling and pain (grinding teeth, swishing tail, repeatedly up and down), fever, and loss of appetite. Urolithiasis is rare in dairy cows and urolithiasis in female ruminants is rarely symptomatic, as the stones usually pass readily. Glomerulonephritis would not be so painful and would not result in blood and pus in the urine. Metritis could result in seeing pus and blood in a free catch urine sample, but the cow is unlikely to be colicky with metritis, and 2 weeks post-partum is a long delay in acute metritis (usually occurs a few days post-partum).

Question 86

There is an appointment today for a work-up on a lame cow. "Playing the odds", what digits are most likely to be involved, because these are the digits most often affected in dairy cattle? a. Lateral front digits b. Medial rear digits c. Medial front digits d. Lateral rear digits

Answer 86

d. Lateral rear digits ## Footnote The correct answer is lateral rear digits. Over 80% of foot disease involving the digits involves the rear digits. Additionally, approximately 85% of these involve the lateral aspect. This is because they bear the majority of their rear limb weight on the lateral claw in the hind. In the front, cattle put most of their weight on their medial claw.

Question 87

You examine a 3-year old beef cow which has been acting depressed for the last 24 hours, and has failed to remain with the herd. The cow's temperature is 104F, (40 C), heart rate is 100 bpm and is pounding loudly, and the respiratory rate is elevated at 42 breaths per minute. The mucous membranes are pale. You take a blood sample back to your nearby clinic and observe the blood smear (see image). The PCV is 20% (24-46%). Of the following, what is the single best, most cost-effective treatment for this cow? a. Imidocarb dipropionate injection b. Procaine penicillin injection c. Vaccinate against parainfluenza-3 d. Whole blood transfusion e. Long acting tetracycline injection

Answer 87

e. Long acting tetracycline injection ## Footnote The blood smear shows multiple round Anaplasma marginale along the outer membrane of red blood cells. Anaplasma marginale is an obligate intracellular bacterium. It is the most prevalent tick-borne pathogen of cattle worldwide and is endemic in tropical and sub-tropical regions. Canada is Anaplasma-free. Infection causes large scale destruction of red blood cells and fever, weight loss, respiratory distress, abortion, and often death. Although some cattle recover, they can become lifetime carriers as reservoirs. Anaplasma ovis can occur in sheep and goats. Anaplasma can often be treated successfully with a single injection of long acting tetracycline (20 mg/kg). When the PCV is below 12%, a blood transfusion may also be needed. In addition, the animal should be given ready access to feed and water. Even with treatment, animals may remain carriers after all clinical signs resolve.

Question 89

An outbreak of psoroptic mange is identified in a herd of cattle. What is the treatment of choice? a. Pyrethrin b. Albendazole c. Ivermectin d. Levamisole

Answer 89

c. Ivermectin ## Footnote The correct answer is ivermectin. Albendazole and levamisole are used to treat worms. Ivermectin is more effective than pyrethrin.

Question 90

Calves that are fed milk replacers containing linseed oil, soybean oil, fish oil, or corn oil are predisposed to what deficiency? a. Vitamin D b. Vitamin E c. Calcium d. Magnesium e. Vitamin K

Answer 90

b. Vitamin E ## Footnote The correct answer is vitamin E. Because these oils are high in polyunsaturated fatty acids, it is necessary to increase the amount of vitamin E provided so that it can scavenge all the additional free radicals that result.

Question 91

You have decided that you need to do an exploratory right flank surgery on a valuable cow because she has colic and abdominal distention, and is passing scant amounts of dark red feces. There are no obvious pings. She is dehydrated (skin turgor is abnormal and eyes sunken) and totally anorectic. The owner reports that she was normal two days ago when he last looked at her closely. On exploratory surgery under local anesthesia you find a hard 6- to 8- inch long by 4-inch diameter mass in the small intestine, as shown in the photo. It is painful to the cow when it is touched. The bowel proximal to the mass is distended and the bowel distal is empty. How would you treat this? a. Close the cow and give antimicrobial drugs, laxatives and IV fluids b. Surgically resect the intussusception c. Euthanize the cow as this is an inoperable tumor d. Perform a surgical bypass of the mass but do not remove it e. Manually reduce the mass and close the cow

Answer 91

b. Surgically resect the intussusception ## Footnote Hopefully you will be able to recognize that the "mass" visualized in this image is an intussusception. After removal, an end-to-end anastomosis of the intestine is performed, and the cow is aggressively treated with antimicrobial drugs and IV fluids with a good content of chloride, such as saline, since these animals are usually suffering from hypochloremic hypokalemic metabolic alkalosis.

Question 92

Which of the following is zoonotic? a. Pseudocowpox b. Bluetongue virus c. Polioencephalomalacia d. Bovine viral diarrhea

Answer 92

a. Pseudocowpox ## Footnote The correct answer is pseudocowpox. Pseudocowpox is a parapox virus.

Question 93

A farmer brings a cow to you with the complaint that the cow is losing weight and not appearing to eat well. On physical exam you find that the tongue is hard and swollen, as shown in the image. How would you treat this cow? a. Sodium iodide b. Euthanasia, and notify the state officials c. Ceftiofur d. Penicillin e. Banamine

Answer 93

a. Sodium iodide ## Footnote The tongue is the area most frequently infected with woody or wooden tongue, although other soft tissues can be infected. The infection is introduced by breaks in the mucosa, allowing the normal rumen inhabitant, Actinobacillus Lignieresii, to invade and cause painful granulomas. The disease can often be successfully treated with IV sodium iodide; although certain other systemic antibiotics including tetracyclines can be used. The sodium iodide is given intravenously once and repeated again in 7-10 days. It is given at a concentration ranging from 5-20%. Ceftiofur cannot be used extra label.

Question 94

Calves that are fed milk replacers containing linseed oil, soybean oil, fish oil, or corn oil are predisposed to what deficiency? a. Vitamin D b. Vitamine E c. Calcium d. Magnesium e. Vitamin K

Answer 94

b. Vitamine E ## Footnote The correct answer is vitamin E. Because these oils are high in polyunsaturated fatty acids, it is necessary to increase the amount of vitamin E provided so that it can scavenge all the additional free radicals that result.

Question 95

What is the causative agent of woody tongue in cattle? a. Pasteurella multocida b. Actinomyces bovis c. Arcanobacterium pyogenes d. Actinobacillus lignierseii

Answer 95

d. Actinobacillus lignierseii The correct answer is Actinobacillus lignieresii. This bacterium is gram-negative and is a normal inhabitant of the rumen and mouth of many cattle; however, when allowed access to soft tissues through a lesion, usually associated with scabrous feeds, it may cause a granulomatous abscessation. A bovis causes lumpy jaw.

Question 96

A group of dairy calves were fed a home-made grain mix that had a high percentage of cottonseed (photo shows seed and oil). Cottonseed is a good source of protein. A few days after being started on this new grain mix, the calves began having problems including dyspnea, and weakness, followed by death in several calves. What is the toxic principle acting here? a. Nicotine b. Cardiac glycoside c. Gossypol d. Tannins e. Cyanide

Answer 96

c. Gossypol ## Footnote Gossypol is a natural constituent of many types of cotton. It acts as an insecticide and protects the plant. The polyphenol binds to iron in cell constituents. It may cause kidney damage, inhibit dehydrogenase enzymes, and uncouple phosphorylation in the cell. Acute gossypol toxicity in calves can be severe.

Question 97

An outbreak of psoroptic mange is identified in a herd of cattle. What is the treatment of choice? a. Pyrethrin b. Albendazole c. Ivermectin d. Levamisole

Answer 97

c. Ivermectin ## Footnote The correct answer is ivermectin. Albendazole and levamisole are used to treat worms. Ivermectin is more effective than pyrethrin.

Question 98

If a veterinarian used both dexamethasone and PGF2-alpha to induce abortion in a cow, the cow was most likely _________ pregnant. a. 9 months b. 2-4 months c. 5-8 months d. 1-2 months

Answer 98

c. 5-8 months ## Footnote The correct answer is 5-8 months. At this point, the corpus luteum and the placenta share the role of providing progesterone to keep the pregnancy going. Elimination of one source of progesterone is not enough to induce abortion, so both drugs are needed.

Question 99

A farmer was shipped ten 2-week old calves several days ago. They seemed initially normal but a few of the calves are now growing poorly and disinterested in eating the milk-replacer. One calf began vocalizing and arching her back and also developed white and sticky feces. She became very dehydrated and died before you arrived at the farm. Necropsy reveals mucosal inflammation of the rumen and parakeratosis of rumen epithelium. You advise the farmer that decreasing stress can reduce the incidence of this problem. Which of the following management aspects should you also carefully review? a. Vaccination program b. Quarantine program c. Vector control program d. Animal housing program e. Feeding program

Answer 99

e. Feeding program ## Footnote The clinical description and pathologic findings are consistent with rumen acidosis, likely secondary to dysfunction of the esophageal groove (also known as reticular groove). To review normal physiology, the esophageal groove (also known as reticular groove) is a specialized part of the ruminant stomach that closes in response to drinking milk, guiding it directly to the abomasum. When dysfunctional, milk goes to the rumen where it is fermented by rumen microbes and converted to volatile fatty acids and lactic acid. The resulting rumen acidosis leads to the clinical signs described in this case. For this reason, this phenomenon is sometimes referred to as rumen drinking. There are a number of predisposing factors to this problem. The major contributors are stress, irregular feeding, feeding poor quality milk replacer, feeding milk at too cold of a temperature (should be body temperature), tube feeding, diarrhea, and bucket drinking. Of the options in this question, the best choice is to review the feeding program because it involves so many of the predisposing factors.

Question 100

A dairy farmer brings you a 6-week old calf for postmortem exam on a nice warm spring day. He has had three 5- to 7-week old calves die in the last week and this one just died an hour ago. They show depressed appetite, fever, and rapid labored breathing before collapsing within a day from the time the first signs are noticed. The calves were born on his farm and have been in good well-ventilated individual hutches with shade. They are fed 12% of their body weight per day in whole milk, plus a calf starter grain, alfalfa hay and free choice water. The major lesions are serosal and subcutaneous petechial hemorrhages and heavy wet red lungs (see image). Based on these pathologic findings, which of the following is the most likely cause of death? a. E. coli septicemia b. Malignant catarrhal fever (MCF) c. Salmonella dublin d. Bovine virus diarrhea (BVD) e. Mannheimia hemolytica bronchopneumonia

Answer 100

c. Salmonella dublin ## Footnote S. dublin tends to cause septicemia in dairy calves 4 to 8 weeks of age, and the lesions described are typical. The organism can be transmitted by carrier cows to neonates at birth or via their milk. The most effective control measures are to cull carriers and vaccinate calves using a modified live S. dublin vaccine.

Question 101

What do you treat brodifacoum toxicity with? a. Potassium bromide b. VItamin K3 c. VItamin K1 d. Vitamin D3 e. Methylene blue

Answer 101

c. VItamin K1 ## Footnote The correct answer is vitamin K1. Brodifacoum is a vitamin K antagonist commonly used in rodenticides. Ingestion of this compound causes hemorrhaging. Treatment for this condition requires vitamin K1 administration for 4-6 weeks.

Question 102

This herd of cattle has been dealing with a Moraxella bovis outbreak in calves. In an effort to control the outbreak, it is important to stop the vector from transmitting the disease. Which one of the following is NOT a factor in the transmission of Moraxella bovis? a. Musca autumnalis b. Sarcoptes scabiei c. Stomoxys calcitrans d. Lyperosia irritans

Answer 102

b. Sarcoptes scabiei The correct answer is Sarcoptes scabiei. Flies are the main vector of M. bovis, a.k.a. pink eye. Stomoxys calcitrans is the stable fly; Haematobia irritans is the horn fly; Musca autumnalis is the face fly. The face fly is one of the most commonly implicated vectors of all the flies. Sarcoptes scabiei is a reportable mite which induces severe pruritus and, as a result, may be economically devastating, but it is not involved in Moraxella transmission.

Question 103

Mycobacterium avium ssp paratuberculosis is most commonly recognized in cattle at which age? a. 6 weeks to 6 months of age b. Less than 6 weeks of age c. 2-5 years of age d. 6 months to 2 years of age e. Greater than 5 years of age

Answer 103

c. 2-5 years of age ## Footnote The correct answer is 2-5 years of age, although younger and older animals can develop Johne`s disease. Mycobacterium avium ssp paratuberculosis is the causative agent of Johne's disease in cattle. It causes wasting, diarrhea, and decreased production. The disease is economically devastating. There is no recommended treatment for the disease. Animals testing positive should be culled.

Question 104

What protein refractometry value on serum is consistent with failure of passive transfer in a three day old calf? a. 4.2 gm/dL b. 6 gm/dL c. 7.0 gm/dL d. 5.2 gm/dL

Answer 104

a. 4.2 gm/dL The correct answer is 4.2 gm/dL. With values between 4.5 and 5.5, it is difficult to make a definitive diagnosis. If the value is above 5.5, you can take a deep breath and relax because you have successful passive transfer!

Question 105

What is the most common mode of transmission for thelazia? a. Aerosol b. Culex mosquitoes c. Direct contact d. Face flies e. Culicoides gnats

Answer 105

d. Face flies The correct answer is face flies. The adult Thelazia live in tear ducts and in the conjunctival sac. Thelazia larvae are regurgitated from the crop of the face fly while feeding on ocular secretions. The worm larvae irritate the eyes and lacrimation, photophobia, conjunctivitis, corneal ulceration, keratitis and small eyelid abscesses.

Question 106

You diagnose an Angus beef cow with ocular lymphoma. What should you recommend to the owners? a. Injectable chemotherapy b. Exenteration of the eye c. Euthanasia d. Enucleation of the eye e. Corticosteroid therapy

Answer 106

c. Euthanasia ## Footnote The correct answer is euthanasia. Meat from cattle affected with lymphoma cannot be used. Treatment for the disease is economically unadvisable for beef cattle. Enucleation is not likely to cure the disease as it is likely systemic.

Question 107

You have diagnosed nitrate poisoning in a group of yearling cattle which were grazing Sudan grass (see photo). Which of the following is the most effective treatment? a. Calcium gluconate b. Digitalis c. Sodium thiosulfate d. Vitamin B12 e. Methylene blue

Answer 107

e. Methylene blue ## Footnote Nitrate toxicosis causes methemoglobinemia, in which the blood appears chocolate brown. As a result, the oxygen carrying capacity and delivery is greatly reduced and the animal may die. Methylene blue is usually administered IV as a 1% to 4% solution, with a total dose of 4 to 15 mg/kg body weight to cattle, for treating nitrate toxicosis. Nitrates are found in high levels in many plants and some water sources. The nitrate is converted in the rumen to nitrite and then absorbed into the blood, which causes oxidation of the heme iron to the +3 ferrous state (called methemoglobin). Methylene blue restores the iron in hemoglobin to its normal (reduced) oxygen-carrying state. This is achieved by providing an artificial electron acceptor for NADPH methemoglobin reductase (RBCs usually don't have one; the presence of methylene blue allows the enzyme to function at 5A? normal levels). The NADPH is generated via the hexose monophosphate shunt.

Question 108

A dairyman's favorite cow was bred by a new bull a few weeks ago and now his cow has pyometra. What agent is most likely responsible for causing the cow's pyometra? a. Campylobacter fetus b. Leptospirosis c. Brucellosis d. Tritrichomonas foetus

Answer 108

d. Tritrichomonas foetus ## Footnote The correct answer is tritrichomonas foetus. This organism is commonly associated with a post-coital pyometra in addition to causing early embryonic death. Campylobacter is a cause of early embryonic death but does not usually result in pyometra. Brucella will result in late term abortion. Leptospirosis is a cause of mid- to late-gestation abortions and not post-coital pyometras.

Question 109

You are asked to evaluate the breeding soundness of a 1-year old, 675 lb Brown Swiss bull. Vital parameters and your general physical examination are unremarkable. You collect semen via electro-ejaculation and note an acceptable semen quantity and quality. Scrotal circumference is 33 cm. You note 2 small penile warts near the tip of the penis that have a broad head and narrow stalk. There are no warts detected elsewhere on the bull and no other abnormalities associated with the penis. What should you recommend to the owner? a. The bull should not be bred until at least 6 months after regression of all warts b. Warts are not contagious but the bull has a very small scrotal circumference and is not considered a good breeding animal c. You suggest vaccination with an autogenous vaccine d. You suggest surgical removal and sexual rest for 2-3 weeks e. The bull should not be bred because he has not yet reached puberty. Warts should be re-evaluated when the bull reaches puberty

Answer 109

d. You suggest surgical removal and sexual rest for 2-3 weeks Penile warts in young bulls are quite common and are caused by bovine papilloma virus-1 (BPV-1) which can also cause warts on the nose or teats. Warts are very contagious and primarily spread by contamination of facility equipment but also spread directly from bull to bull. BPV-1 infection is not associated with other health problems. The treatment of choice for penile warts is surgical removal. Surgical damage to the warts frequently stimulates an immune response against BPV-1. Healing is usually complete within 2-3 weeks. Autogenous vaccines have been used to treat penile warts but this is rarely practiced now due to cost and risk of severe reactions and relatively little benefit compared to surgical removal. It is not necessary to wait 6 months before breeding. Bulls typically reach puberty at 9-11 months of age depending on breed. Scrotal circumference of a 1 year-old bull also varies by breed but \>30 cm is typically recommended for breeding at this age.

Question 110

At what age during gestation is a fetus most likely to become persistently infected with the noncytopathic form of bovine viral diarrhea? a. Fetus infected between 150-200 days of gestation b. Fetus infected at 320 days of gestation c. Fetus infected between 200-270 days of gestation d. Fetus infected before 125 days of gestation

Answer 110

d. Fetus infected before 125 days of gestation ## Footnote The correct answer is fetus infected before 125 days of gestation, with most of those occurring before 100 days. A fetus infected with BVD at any time during gestation can be aborted or be a stillbirth. Most congenital defects associated with BVD occur when a fetus is infected between days 90-150 of gestation. Persistent infection of fetuses is seen when they are infected before 125 days of gestation. This is of importance because they have a potential to affect many other herdmates since they shed virus but may show no clinical signs. About half of the persistently infected calves will die during their first year of life. Clinical signs in BVD carriers vary greatly. They may range from an asymptomatic animal to one that has diarrhea, fever, pneumonia, and oral ulcerations. Additionally, you may have infected animals that are just repeat breeders. You may also see abortions, stillbirth, and congenital anomalies. The most common congenital anomaly associated with BVD is cerebellar hypoplasia, but there are many others.

Question 111

In cattle, shipping fever is most commonly caused by this organism. a. Haemophilus pleuropneumoniae b. Mannheimia hemolytica c. Pasteurella multocida d. Mycoplasma bovis

Answer 111

b. Mannheimia hemolytica The correct answer is Mannheimia hemolytica. Basically, most cattle carry this organism in their respiratory tract and when an animal is stressed, low concentrations of pathogenic strains can proliferate and infect the lungs. Haemophilus somnus is only an occasional cause of shipping fever (fibrinous pneumonia). Mycoplasma and Pasteurella multocida are not really considered causes of shipping fever, but if those are "stressing" the animals then they may succumb to shipping fever.

Question 112

Nervous coccidiosis is a disease of cattle of what age? a. Less than 1 months of age b. Between 12-24 months of age c. Less than 1 year of age d. Greater than 24 months of age

Answer 112

c. Less than 1 year of age ## Footnote The correct answer is nervous coccidiosis is a disease of cattle less than one year of age. This disease is caused by an enteric infection of Eimeria spp. It is thought that the coccidian produces a neurotoxin which results in the neurologic form of the disease.

Question 113

What is the most common direction of a coxofemoral luxation in cattle? a. Cranial and ventral displacement b. Caudal and dorsal displacement c. Cranial and dorsal displacement d. Caudal and ventral displacement

Answer 113

c. Cranial and dorsal displacement ## Footnote The correct answer is cranial and dorsal displacement. Usually these cows will be down after parturition and will fail to respond to hypocalcemia therapy. Dystocia and sciatic or obturator paralysis will increase the risk of luxation.

Question 114

You are in charge of a slaughter house and are asked about why so many of the culled dairy cattle in a recent shipment have liver abscesses (see photo) and what can be done about it. The abscesses result in a significant financial loss for the owner because the liver is condemned, and he is concerned. What is the cause? a. Black disease b. Foot abscesses showering bacteria to the liver c. LIver fluke migration d. Traumatic reticuloperitonitis with hepatic involvement e. Rumen acidosis

Answer 114

e. Rumen acidosis Dairy cattle which are fed a high concentrate diet should be gradually introduced to it. Even so, an additional dietary buffer may be needed. The herd veterinarian should check rumen pH on about 5 high-producing cows by needle stick of the rumen 2 to 3 hours after they are fed. If some fall below pH 5.5, additional sodium bicarbonate should be added to the ration. The low rumen pH causes rumenitis allowing bacteria to translocate through the mucosa and be filtered from the hepatic portal circulation by the liver, resulting in one or more hepatic abscesses. The key to picking rumenitis is that there are many culled dairy cattle coming in with this problem of hepatic abscess. If it were feet or hardware it would only occasionally lead to a liver abscess.

Question 116

You are called to a small beef and sheep ranch where the owner is concerned about a 1-year old steer which has cloudy eyes, mucoid nasal discharge, thickened and cracked skin, and diarrhea. You examine the animal and find T=107F or 41.7 C, HR=105, RR=40, corneal opacity and thick white nasal discharge (see photo), thick cracked skin all over the animal, enlarged prescapular lymph nodes, and diarrhea with small amounts of blood in it. There are also some oral erosions. Based on the PE you tentatively diagnose this condition. a. Gossypol toxicity b. Bovine papular stomatitis c. Malignant catarrhal fever (MCF) d. Bovine viral diarrhea (BVD) e. Vesicular stomatitis

Answer 116

c. Malignant catarrhal fever (MCF) ## Footnote MCF is caused by a herpes virus carried by sheep in North America and called ovine herpesvirus type 2. The virus affects lymphocytes and allows the animal`s own killer cells to attack blood vessels, resulting in arteritis. Arteritis results in multisystemic signs, high fever, and enlarged lymph nodes. The acute severe form such as described here is usually fatal. While a small number of cattle with BVD may develop corneal opacity, they do not usually have the enlarged lymph nodes and the combination of other signs seen with MCF.

Question 118

What is the most common ocular tumor in cattle? a. Lymphoma b. Adenoma c. Squamous cell carcinoma d. Melanoma

Answer 118

c. Squamous cell carcinoma The correct answer is squamous cell carcinoma. It occurs most in cattle which lack pigment in the lids and in older beef cattle (particularly Herefords).

Question 119

What is the approximate gestation length of a cow? a. 280 days b. 250 days c. 300 days d. 320 days

Answer 119

a. 280 days The correct answer is 280 days.

Question 120

Which of the following is not a viral cause of abortion in cattle? a. Infectious bovine rhinotracheitis b. Bovine viral diarrhea c. Akabane virus d. Bovine papular stomatitis

Answer 120

d. Bovine papular stomatitis ## Footnote The correct answer is bovine papular stomatitis. The other ones are viral causes of abortion.

Question 121

About 1 hour after a difficult labor where the calf had to be pulled out with force, the cow goes down. She is pale and her heart rate is 100/min. What happened? a. Uterine tear b. Hypocalcemia c. Pelvic fracture d. Obturator paralysis

Answer 121

a. Uterine tear ## Footnote The correct answer is uterine tear. With a traumatic fracture or damage to nerves, the cow would have gone down right away rather than an hour later. Hypocalcemia is possible but less likely in this case where the calf had to be forcibly extracted which can result in a uterine tear, and would be unlikely to make her pale and tachycardic.

Question 122

You examine a 4-year old dairy cow which has markedly decreased in milk production over the last lactation, and find T=103F (39.4 C), HR=100/min, brisket edema (see photo) and enlarged/dilated jugular veins. The heart is muffled and you hear occasional splashing sounds. You tell the farmer the cow most likely has \_\_\_\_\_\_\_\_\_. a. Gossypol toxicity b. Endocarditis c. Traumatic reticulopericarditis d. Hereditary cardiomyopathy e. Heart base tumor (lymphoma)

Answer 122

c. Traumatic reticulopericarditis ## Footnote The clinical signs all lead to the fact that this cow has heart failure. The main causes are pericarditis, endocarditis, heart base lymphoma, and hereditary muscle disorders. Calves also suffer from gossypol toxicity with heart failure. The muffled splashy heart sounds lead to traumatic reticulopericarditis, associated with a metallic foreign body which pierced the reticulum.

Question 123

A 4 month old Holstein heifer has a loud cough, tachypnea, diarrhea, and ill thrift of 8 days duration. However, there are no signs of sepsis, depression, or loss of appetite. On physical exam, you could hear crackles and wheezes over the lung fields and a harsh bronchial tone cranioventrally. Given this presentation what is the most likely diagnosis? a. Shipping Fever b. Enzootic pneumonia c. Aspiration penumonia d. Moldy sweet potato poisoning

Answer 123

b. Enzootic pneumonia ## Footnote The correct answer is enzootic pneumonia. This disease is multifactorial but is mainly a result of poor housing and environment (poor sanitation and ventilation). Calves with enzootic pneumonia will have cranioventral consolidation and many times they have diarrhea as a result of being infected with Eimeria bovis (like this one). Shipping fever (fibrinous pleuropneumonia) will most likely present with more systemic signs, which is key in differentiating the two diseases. Aspiration pneumonia will probably not result in diffuse lung pathology without also causing systemic signs. Moldy sweet potato poisoning is a good differential and will result in respiratory disease followed by death, but there was no history of exposure here. However, these animals will typically present with more acute respiratory distress and will probably not survive for 8 days, as death usually ensues 2-5 days after exposure. The principal toxin is ipomeanol which is produced by sweet potatoes infected with Fusarium javanicum or F. solani. Ipomeanol will destroy clara cells and type I pneumocytes.

Question 125

A 7-month old feedlot steer has died after exhibiting severe fever, dyspnea, cough and respiratory distress. On post mortem there is evidence of fibrinopurulent bronchopneumonia (see image). What bacterium is most likely to be the cause of this syndrome? a. Mannheimia hemolytica b. Trueperella pyogenes (formerly Arcanobacterium pyogenes) c. Pasteurella multocida d. Bovine herpes virus type 4 e. Mycoplasma bovis

Answer 125

a. Mannheimia hemolytica Other agents may also be isolated, but this is recognized as the worst pathogen in bovine pulmonary disease. It was formerly called Pasteurella hemolytica.

Question 126

A farmer who raises valuable registered Holstein cattle calls you in a panic to tell you that he has just mistakenly orally administered a gallon of propylene glycol to a 600kg cow with constipation, thinking it was mineral oil. He asks what toxic effects this could have and what you can do about preventing/minimizing the toxic effects. Of the following choices, what is the correct treatment at this point? a. Urinary acidification using an anionic diet b. Calcium gluconate IV c. Intravenous and oral fluids to cause diuresis d. Large doses of NSAIDs every 8 hours e. General anesthesia to prevent seizures

Answer 126

c. Intravenous and oral fluids to cause diuresis This amount of propylene glycol is likely to cause several problems: first the CNS effects of depression and disorientation, next at 12 to 24 hours come cardiovascular and pulmonary signs, along with severe metabolic acidosis. From 24 to 72 hours renal toxicity may predominate due to tubular damage. The best treatment is diuresis using isotonic sodium containing fluids for the next several days.Since there metabolic acidosis, using sodium bicarbonate and some IV glucose to help maintain blood glucose are also helpful. You can also bind some of it in the rumen by giving activated charcoal immediately, but propylene glycol is poorly bound to charcoal. By three days the propylene glycol and toxic products are usually eliminated. Daily checks on the serum creatinine can help determine when fluids can safely be stopped. In humans they might also use a drug called Fomepizole ( Antizol) and/or IV ethyl alcohol (600-800 mg/kg IV) and dialysis if needed. Other recommendations include the B vitamins thiamine and pyridoxine

Question 127

All of the following are contagious mastitis pathogens of cows except for \_\_\_\_\_\_\_\_\_\_\_\_. a. Mycoplasma b. E. coli c. Streptococcus agalactiae d. Staphylococcus aureus

Answer 127

b. E. coli ## Footnote The correct answer is E. coli. This pathogen is an environmental pathogen.

Question 128

A 6-year old Friesian cow presents to you with a mass on the left mandible (see image). The farmer reports that the mass has developed over the last several weeks and the cow has recently had some difficulty eating and lost weight. On examination, the mass is firm, immobile, and painful on manipulation. You note a thick discharge with small granular particles. Based on the most likely diagnosis, what should you tell the farmer? a. Treatment with sodium iodide intravenously is likely curative but the cow's milk and meat will not be suitable for human consumption for 120 days b. Intravenous penicillins are likely to be effective c. The most effective treatment is oral sodium iodide d. Treatment is unlikely to be successful and the cow should be culled

Answer 128

d. Treatment is unlikely to be successful and the cow should be culled ## Footnote This is a case of Actinomyces bovis or "lumpy jaw". The keys to the diagnosis are the firm mass that is immobile over the mandible. The presence of "sulfur granules" in the discharge is also a characteristic finding with this disease. Unfortunately, simply making the diagnosis is not sufficient to answer this question correctly. All of the answer choices are potential treatments for lumpy jaw but this represents a moderate to severe case which is unlikely to respond to treatment due to difficulty in achieving the necessary antibiotic concentration over a sustained period. Therefore, the best answer choice in this case is to cull the cow.

Question 129

A herd of beef cattle in northwestern Canada escaped through a broken fence and grazed near wild bison during the summer mating season. What reportable disease (most commonly associated with bison) should the rancher be worried about these cattle having contracted from the bison? a. Anthrax b. Epizootic hemorrhagic disease c. Chronic wasting disease d. Bovine spongiform encephalopathy e. Encephalitozoonosis

Answer 129

a. Anthrax When beef cattle graze pasture that bison have contaminated with nearly indestructible anthrax spores, the cattle can get the disease as well. Caused by *_Bacillus anthracis_* (note: "Boxcars" appearance). See depression, respiratory or cardiac distress, staggering, sudden death. Temp can hit 107^oF (41.5^oC). May see bloody discharges from natural body openings. Some infections characterized by localized, subcutaneous, edematous swellings on ventral neck, thorax, and shoulders Outbreaks of naturally-occurring _anthrax_, occur in bison, cattle and sheep with some regularity in northern Canada and the northwestern U.S. Grazing animals typically become infected from soil spores. Pigs, dogs, cats (carnivores) are relatively resistant Anthrax is a _Category A bioterrorism agent_. **REPORTABLE.**

Question 130

A 2 year old Angus cow is presented with weakness of the hind limbs and a staggering gait. On physical exam, the heart rate and respiratory rate are slow and irregular, and the pupils are dilated. The cow's breath and urine smell like the odor of mouse urine. Suddenly the cow's pulse becomes rapid and thready, she collapses, and dies of apparent respiratory failure. Which one of the following plants is most likely to have caused this spectrum of clinical signs? a. Pinus ponderose (Western yellow pine) b. Veratrum spp (False hellebore, Skunk cabbage) c. Centaurea spp (Knapweed, Yellow start thistle) d. Conium maculatum (Poison hemlock) e. Tetradymia spp (Horsebrush)

Answer 130

d. Conium maculatum (Poison hemlock) Poisoning with Conium maculatum (Poison hemlock) is responsible for the death of this cow. At least 8 toxic piperidine alkaloids have been isolated from poison hemlock. Coniine is found in seeds and the mature plants; g-coniceine is found in young growing plants. Poison hemlock is toxic to all livestock and humans. Signs of toxicity develop 1-2 hours after ingestion and are usually fatal. Signs include nervousness, trembling, weakness especially of the hind limbs, weak pulse, irregular heart rate, recumbency, coma, and death. A mousy odor exuding from the urine and breath is pathognomonic. Ingestion of poison hemlock during gestation causes arthrogyposis and other congenital defects in cattle, goats, and pigs.

Question 131

A beef ranch has suffered 12 acute deaths of 2-4 month old calves in the past six months. The owner of the ranch states that the animals appeared severely weak and depressed just before dying. On some of them, he noticed that they were having trouble breathing and had a frothy nasal discharge. You perform a necropsy on a calf that died yesterday. Findings included bilaterally symmetric muscular atrophy. The skeletal muscle appears pale and dry in appearance with white streaks running along muscle bundles. You also notice that there are several calves in the ranch which are having trouble rising, and their musculature appears swollen, hard, and painful. What is the most likely diagnosis? a. Oleander toxicity b. Clostridial myositis c. Gossypol toxicity d. Septicemia e. Vitamin E and selenium deficiency

Answer 131

e. Vitamin E and selenium deficiency ## Footnote The correct answer is vitamin E and selenium deficiency (white muscle disease). The clinical signs are somewhat compatible with the other answers; however the necropsy results are diagnostic for white muscle disease. There is both a cardiac form, in which animals die acutely, and a skeletal muscle form, in which animals don't die acutely but show clinical signs. In this particular question, the ranch was suffering from both forms. Remember that oleander and gossypol are both cardiotoxic and can cause acute death. Given the necropsy findings, clostridial myositis would be unlikely. Selenium is essential for glutathione peroxidase, deiodinase, and selenoprotein-P to work. Glutathione peroxidase breaks hydrogen peroxide and lipoperoxide into water or harmless alcohols.

Question 132

How many maxillary incisors do bulls have? a. 0 b. 2 c. 1 d. 3 e. 4

Answer 132

a. 0 ## Footnote The correct answer is 0. Ruminants do not have maxillary (upper)incisors.

Question 133

A group of 3-4 month old dairy calves have oral ulcers and appear reluctant to eat hay because their mouths are sore. You examine 3 affected calves and find that they are of normal size and weight, have normal feces and normal TPR, but have ulcers around the dental pad and gums. The poor quality alfalfa hay contains some grass as shown in the photo. Based on these findings, what is the correct diagnosis? a. Bluetongue b. Bristle grass (Setaria lutescens) irritation c. Actinobacillosis d. Bovine virus diarrhea e. Water grass poisoning

Answer 133

b. Bristle grass (Setaria lutescens) irritation ## Footnote Yellow bristle grass contains sharp miniature barbs that stick into the mucosa of young cattle and horses and cause ulcers. Simple removal from the diet results in healing.

Question 134

A dairyman is trying out a new feeding protocol to help increase milk production. Since he instituted the change a week ago, several of his best cows have become mildly depressed, dropped in milk production, and several have developed diarrhea. A needle aspirate from the rumen two hours after feeding reveals an average pH of 5.2 among these cows. What is the most likely diagnosis? a. Hardware disease (TRP) b. Grain overload c. Left displaced abomasum d. Vagal indigestion

Answer 134

b. Grain overload ## Footnote The correct answer is grain overload, also known as rumen acidosis or lactic acidosis. The change in feeding protocol coupled with the fact that rumen pH is below 5.5 in the most productive cows make this the correct answer.

Question 135

A beef rancher in Nevada calls you in to see some of his young cattle which have been out on remote new range on which he recently purchased a lease. The range consists of sagebrush and bunch grasses in a dry alkaline environment. The affected calves are 6- to 8- months of age and are small, thin, and poorly muscled. You examine 3 affected calves. On PE you find normal temperatures, but elevated HR (70 to 92) and RR (30 to 36) on a day when the ambient temperature is only 70F (21 C). The calves have pale mucous membranes, their hair coat color is washed out and pale (see photo), and the perineum is stained with diarrhea. The rancher had an analysis of plant material trace minerals done when he purchased the lease and found the following: Sulfur 40 ppm, iron 3.2 ppm, copper 12 ppm, molybdenum 15 ppm and cobalt 0.2 ppm. Based on this analysis and the condition of the calves, what compound should you treat the group with? a. Protein supplement such as cottonseed b. Injections of vitamin B12 for cobalt deficiency c. Copper supplement such as copper oxide orally d. Worm all calves with ivermectin e. Iron injections for iron deficiency anemia

Answer 135

c. Copper supplement such as copper oxide orally ## Footnote This is classical secondary copper deficiency. Primary copper deficiency is caused by an absolute low level of copper in the feed, while secondary copper deficiency is caused by interference of absorption of copper and increased rate of excretion of copper due to the presence of molybdenum and sulfates (iron and other metals can also interfere). A rule of thumb is that copper levels in feed should be at least five times those of molybdenum to avoid secondary copper deficiency. Calves may be anemic and grow poorly, and often have diarrhea and a washed out hair coat color (achromotrichia). Low serum copper levels can be indicative of a problem, but the definitive diagnosis relies on liver biopsy to determine liver copper levels, since the liver is the major copper storage site. Treatment is with excess copper, by feeding copper oxide in molasses or salt. Copper can also be delivered by injection or by slow release wires or bolus given orally.

Question 136

The cow pictured had a dystocia that was finally pulled about one hour ago, resulting in obturator paralysis. She has been unable to rise since then and is now termed an alert downer cow. You examine her and determine that she has a normal temperature, normal heart sounds, does not have any fractures and appears to be metabolically normal and alert. The owner believes she is valuable and wishes to save her. What is the best course of treatment with the best prognosis at this point? a. Give her IV calcium and antibiotics b. Float tank c. Put a good bed of straw under her and roll her every hour d. Put her in a sling e. Use electrical nerve stimulation twice daily to help the obturator nerve heal quickly

Answer 136

b. Float tank ## Footnote Some years ago float tanks appeared commercially. They are the most effective means of managing down cows, and have success rates over 50% if the cow is floated soon after the problem occurs and if there is no other underlying problem such as fracture, hypocalcemia, spinal tumor, peritonitis etc. The tank on wheels is moved next to the down cow, and the cow is rolled onto a mat next to the tank. She is then winched into the tank, the ends are attached in place, and 102-105F water is run into the tank. The cow floats up as it fills and is eventually able to stand using flotation to aid her. This improves circulation and prevents further pressure damage to nerves and muscles. If there is one leg that is knuckling, a splint or fiberglass cast can be applied when the tank is drained in 24 hours, after which she is again floated. Slings do not work well for cattle.

Question 137

You are called early one cold spring morning to see a 5-year old dairy cow which is down in the corral. She freshened three days ago and is fed TMR. You find her to be barely responsive and unable to assume or maintain sternal recumbency, T=98F or 36.7 C, Hr=100/min and weak, and there is no rumen motility. The uterine lochia is red and mucoid. On rectal exam you find normal feces and a full bladder. How should you treat this cow? a. Blood transfusion b. IV saline, large volume c. IV calcium d. IV magnesium e. Broad spectrum antibiotics

Answer 137

c. IV calcium ## Footnote This cow has the history and classic signs of hypocalcemia, also called milk fever. Skeletal, cardiac and smooth muscle weakness lead to the signs, and she is unable to maintain her body temperature in cold weather.

Question 138

How soon after administration of a dose of dexamethasone for induction of parturition in a cow do you expect parturition? a. 12 hours b. 8 days c. 48 hours d. 24 hours

Answer 138

c. 48 hours The correct answer is 48 hours. Parturition may occur anytime between 2 and 7 days but on average it occurs on the second day. A dose of 25-30 mg IM is sufficient.

Question 139

A diagnostic lab reports to you that they have used fluorescent antibody against rotavirus to stain the small intestine of a 10-day old calf you submitted because it had died with diarrhea. They show the image to you (see image). What can you conclude caused calf's diarrhea? a. Cryptosporidia b. No conclusion, since cause cannot be determined c. Bovine viral diarrhea (BVD) d. Rotavirus e. Salmonella

Answer 139

d. Rotavirus ## Footnote The tissues fluoresce brightly, indicating viral antigen of rotavirus is present in cells.

Question 141

Which of the following is zoonotic? a. Polioencephalomalacia b. Bovine viral diarrhea (BVD) c. Pseudocowpox d. Bluetongue virus

Answer 141

c. Pseudocowpox ## Footnote The correct answer is pseudocowpox. Pseudocowpox is a parapox virus.

Question 142

Which human disease has Mycobacterium avium ssp paratuberculosis been associated with, although the debate is still going strong? a. Crohn's disease b. Creutzfeldt-jakob disease c. Systemic lupus erythematosus d. Fabry's disease

Answer 142

a. Crohn's disease ## Footnote The correct answer is Crohn's disease. Creutzfeldt-Jakob disease has been associated with bovine spongiform encephalopathy.

Question 143

What is the mechanism of weight loss in cattle infected with Johne's disease? a. Starvation b. Excessive protein carabolism c. Protein-losing enteropathy d. Protein-losing nephropathy

Answer 143

c. Protein-losing enteropathy The correct answer is protein-losing enteropathy. The acid-fast Mycobacterium avium ssp paratuberculosis results in chronic granulomatous bowel disease, and albumin is lost into the gut.

Question 144

Just after Christmas, a dairy herd of 200 cows in the northeastern US has experienced an outbreak of diarrhea in 40% of the adult cows, with a resultant drop in appetite and milk production. The animals go to pasture in the spring, summer and fall, but in winter they are housed in a barn. The 2 year-old cows seem most severely affected. You examine two affected animals and find brownish fetid liquid feces full of bubbles. There are clots of blood in the feces of one of the animals. Temperatures are normal, but HR=90 (60-70 beats/min), and they appear to be slightly dehydrated. Rumen motility is weak and the rumen is relatively empty. No other obvious abnormalities are noted. Yesterday the dairyman, at your instruction, submitted a CBC and feces to the diagnostic lab. They report that the CBC is normal in both animals, and both are negative for parasite ova. Given the history, age group affected, clinical signs and lab results, which of the following is the most likely diagnosis? a. Clostridium perfringens type A hemorrhagic bowel syndrome b. Type 2 Ostertagia infestation c. Salmonella typhimurium d. WInter dysentery e. Johne's disease

Answer 144

d. WInter dysentery Winter dysentery is an epidemic disorder of housed cattle, usually occurring in cold months and affecting 10-90% of adult cows. If fever occurs at all, it usually precedes the diarrhea phase. The disease is thought to be caused by coronavirus, and lesions involve the colon. In typical outbreaks, the disease runs its course in weeks and the herd becomes immune and recovers, although milk production may not recover to previous levels. With Salmonella typhimurium, the cows would be sicker, febrile, have abnormalities in the CBC compatible with endotoxemia (neutropenia or neutrophilia), and an increased plasma fibrinogen. In a severe Salmonella typhimurium outbreak, some cows would likely die. The scenario described is not compatible with a diagnosis of Johne's disease. Although a few individual animals in a herd might develop type 2 Ostertagia, a herd outbreak would be highly unlikely, especially involving older cows. With Clostridium perfringens type A, there is a low morbidity and high mortality; signs of small intestinal obstruction develop, and if feces are passed they are very dark and bloody.

Question 145

A 9-year old Friesian cow has swollen eyelids (see image). You examine the cow and note marked blepharospasm and ocular discharge. You perform a fine needle aspirate and a representative slide is shown (Wright-Giemsa stain 100x oil objective). Which of the following should you tell the farmer about this cow? a. The cow has lymphosarcoma and sunlight and pigmentation play a role in development b. The cow has lymphosarcoma which may have a viral etiology c. The cow has infectious bovine rhinotracheitis and all cattle should be tested d. The cow has squamous cell carcinoma which has a heritable component e. The cow has squamous cell carcinoma which is not a clinically or economically important disease

Answer 145

d. The cow has squamous cell carcinoma which has a heritable component This is a case of ocular squamous cell carcinoma (also known as "cancer eye") which is one of the most common neoplasms of cattle and causes significant economic loss due to shortened productive life and condemnation at slaughter. The etiology is multifactorial but is believed to have a heritable component as well as association with sunlight, eyelid pigmentation, and nutrition. The diagnosis can be made from the clinical presentation and fine needle aspirate showing a cluster of epithelial cells with anisocytosis and basophilic, vacuolated cytoplasm.

Question 146

A group of Angus heifers were turned into an old corral area 8 hours earlier in the day. Now one heifer has convulsed and died and several have dyspnea, polypnea, and weakness. You arrive and, after a quick physical exam on one, take a blood sample, which is chocolate-brown in color. The plants shown in the photo contain what toxic principle? a. Oxalates b. Nitrate c. Tryptophan d. S-methylcysteine sulfomide e. Cyanide

Answer 146

b. Nitrate The plant shown in the picture is Amaranthus. Amaranthus is commonly called pigweed and accumulates nitrates. Nitrates are converted in the rumen to nitrites, which convert hemoglobin to methemoglobin (Fe+3), which cannot bind or transport oxygen. Even if you cannot identify the plant in the photo, the chocolate-brown color of the blood should lead you to the correct answer of nitrate poisoning.

Question 147

Which of the following is most appropriate for increasing the rumen pH of a cow with rumen acidosis to the optimum range? a. Magnesium oxide b. Propylene glycol c. Bismuth subsalicylate d. VInegar

Answer 147

a. Magnesium oxide The correct answer is magnesium oxide, which becomes Mg OH in the rumen. You may also use magnesium hydroxide or magnesium carbonate. Vinegar will cause acidification of the rumen and is therefore a poor choice. Propylene glycol and bismuth subsalicylate will not affect rumen pH significantly.

Question 148

Animals with a lesion of CN VI will exhibit \_\_\_\_\_\_\_\_\_\_\_? a. Lateral strabismus on contralateral side b. Medial strabismus on contralateral side c. Lateral strabismus on ipsilateral side d. Medial strabismus on ipsilateral side

Answer 148

d. Medial strabismus on ipsilateral side The correct answer is medial strabismus on ipsilateral side. CN VI controls the lateral rectus, and loss of function of this muscle will pull the globe medially.

Question 149

The image shows a radiograph of a valuable three-week old dairy calf which is very lame. What is the correct diagnosis? a. Arthritis b. Osteosarcoma c. Septic arthritis and osteomyelitis d. Fractured distal third metacarpal e. Fescue foot

Answer 149

c. Septic arthritis and osteomyelitis ## Footnote The destructive lesions in both joint and bone in an animal this age means infectious process. This needs to be cultured, vigorously lavaged or surgically opened and flushed, followed by aggressive systemic antimicrobial drug therapy with appropriate drugs.

Question 150

What is the causative agent of red water disease (bacillary hemoglobinuria) in cattle? a. Clostridium hemolyticum (Cl Novyi type D) b. Clostridium chauvoei c. Mannheimia hemolyticum d. Clostridium perfringens

Answer 150

a. Clostridium hemolyticum (Cl Novyi type D) ## Footnote The correct answer is Clostridium hemolyticum, also known as Cl Novyi type D. The organism resides in the liver until anaerobic conditions develop, and then they start replicating and producing toxins.

Question 151

You are performing health checks on a beef ranch after an E. coli O157:H7 outbreak was detected due to contaminated crops in a nearby vegetable farm. Which of the following is an appropriate way to identify and test suspected carriers? a. Send a lymph node biopsy to a diagnostic lab for histopathology and immunohistochemistry from cattle with lymphadenopathy b. Send stool to a diagnostic lab for fecal flotation and Baermann examination in cattle that are emaciated or underweight c. Send swab of sputum or respiratory secretions to a diagnostic lab for O157:H7 PCR from cattle that are coughing or showing respiratory distress d. Send stool to diagnostic lab for O157:H7 specific fecal culture from all cattle. e. Send stool to diagnostic lab for O157:H7 PCR from cattle displaying signs of hematochezia

Answer 151

d. Send stool to diagnostic lab for O157:H7 specific fecal culture from all cattle. E. coli O157:H7 is an enterohemorrhagic strain of E. coli that produces "Shiga-like toxins" which cause illness in humans. The bacteria can exist in the intestines of healthy, normal cattle without causing signs or symptoms; therefore, there are no specific signs to look for when trying to identify suspects. A stool culture can detect the bacterium, but must be specifically requested. The sample is usually cultured on sorbitol-MacConkey (SMAC) agar. On SMAC agar, O157 colonies appear clear due to their inability (unlike other E. coli serotypes) to ferment sorbitol. Non-sorbitol fermenting colonies are tested for the somatic O157 antigen before being confirmed as E. coli O157. Like all cultures, diagnosis is slow using this method, and swifter diagnosis is possible using PCR techniques. A PCR to detect Shiga-like toxin specific to O157-H7 would be an equally good choice. You would pick culture or PCR based on speed and cost. In humans, common signs of infection are severe, acute hemorrhagic diarrhea and abdominal cramps, usually without fever. In most cases, the illness resolves in 5 to 10 days.

Question 152

You examine a 3-year old Holstein dairy cow on a small farm that pastures the animals every day in the summer. This cow, purchased as a 2-year old springer, was producing 80 lbs of milk per day in the 4th month of her lactation, but she suddenly lost a tremendous amount of weight in the last month (see photo) and developed watery green diarrhea. She has a normal TPR but is weak and rail thin. What should you tell the owner that you suspect the cow has? a. Salmonellosis b. Paratuberculosis (Johne's disease) c. Fatty liver d. Grain overload (lactic acidosis) e. Ostertagiasis

Answer 152

b. Paratuberculosis (Johne's disease) Caused by Mycobacterium avium ssp paratuberculosis, this infectious disease causes a granulomatous ileitis and colitis. Diarrhea usually results. The affected bowel dumps albumin into the lumen, and the cow can lose weight extremely rapidly, although this is highly variable. Confirmatory tests such as a serum ELISA should be done.

Question 153

A 6-month old feedlot steer, which entered the feedlot 4 weeks ago, has lost weight and is now showing an enlarged left flank as shown in the image below. On exam, you find the left side of the abdomen to be gas-filled under moderate pressure, and the rumen to be otherwise poorly filled and with poor motility. Based on percussion and auscultation, the animal also appears to have chronic bronchopneumonia. What is the most likely cause of the rumen malfunction? a. Frothy bloat b. Type 3 vagal indigestion c. Free gas bloat, failure to eructate d. Left displaced abomasum e. Cecal dilation

Answer 153

c. Free gas bloat, failure to eructate This is sometimes called Type 1 vagal indigestion, or free gas bloat. It is frequently associated with swollen mediastinal lymph nodes caused by pneumonia. The signals to or from dorsal rumen receptors, which detect gas pressure and open the cardia, are compromised such that eructation does not occur normally and free gas bloat occurs. This in turn causes the calf to feel full and it eats poorly and loses weight. One needs to treat the pneumonia and perhaps create a temporary rumen fistula to allow the escape of gas until eructation returns to normal.

Question 154

What is the significance of post-estrual hemorrhage in a cow? a. It is 24-36 hours before ovulation b. It has been 12-24 hours since ovulation c. Breed her in 36 hours d. A uterine artery has ruptured during estrus

Answer 154

b. It has been 12-24 hours since ovulation ## Footnote The correct answer is it has been 12-24 hours since ovulation; therefore it is too late to breed. Post-estrual hemorrhage is normal in cattle. Additionally, hemorrhage is only seen post-estrus unlike other species. The hemorrhage comes from the endometrium.

Question 155

A dairy cow is mounting another cow. Which is in heat? a. The cow that is mounted b. Neither cow c. Both cows d. The cow that is mounting

Answer 155

a. The cow that is mounted ## Footnote The correct answer is the cow that is mounted. This gives off hormonal cues that other cows may pick up on and lead to them mounting her irrespective of whether the cow doing the mounting is in heat. There are occasionally other reasons for a cow to mount another, including dominance displays, but this is not usual in normally cycling dairy cows. Thus the best answer is the cow that is mounted.

Question 156

An owner suspects that he has trichomoniasis in his cattle herd. What clinical signs can you tell him to look for? a. The bulls will have a thick preputial discharge b. Cows will have metritis c. Poor calving percentage d. Abortion

Answer 156

c. Poor calving percentage ## Footnote The correct answer is that they are usually asymptomatic, but by the time calving occurs there is likely to be a poor calving percentage. Neither the cow nor bull appear to be remarkably clinically affected. Rarely, one may see a very mild discharge from the cow after early embryonic death, and if there is a pyometra at the time of pregnancy check one could be suspicious. Abortion is not the correct answer because cows don't really abort anything, they just return to heat at an extended interval after being bred.

Question 157

Maple syrup urine disease is a genetic disorder associated with spongiform changes in the brain and caused by a deficiency of this enzyme in Hereford and polled Shorthorn calves. It usually shows up at 2 to 3 days of age. Which of the following enzymes is the correct one ? a. Pyruvate kinase b. Carnitine acyltranslocase c. Acetyl-CoA carboxylase d. Branched-chain ketoacid decarboxylase

Answer 157

d. Branched-chain ketoacid decarboxylase ## Footnote The correct answer is branched-chain ketoacid decarboxylase, which will cause accumulation of 2-keto-3-methylvaleric, 2-ketoisocaproic, and 2-isovaleric acids along with their precursors isoleucine, leucine, and valine. These are excreted in the urine and result in a burnt maple syrup smell (hence the name of the disease). This hereditary disease causes an encephalopathy. Acetyl-CoA carboxylase turns acetyl-CoA into malonyl CoA in fatty acid synthesis. Carnitine acyl translocase helps bring fatty acids across the inner mitochondrial membrane for degradation. Pyruvate kinase turns phosphoenol-pyruvate into pyruvate in the glycolysis pathway.

Question 158

Which of the following zoonotic pathogens is most likely to be acquired from treating a 10 day old dairy calf with diarrhea? a. Cryptosporidium parvum b. E. coli O157 c. Leptospira pomona d. Francisella tularensis e. Staphylococcus aureus

Answer 158

a. Cryptosporidium parvum ## Footnote Cryptosporidium is a major cause of calf diarrhea and a few oocysts can be infective to humans and cause diarrhea lasting several days.