BOVINE

Question 1

Which of the following is the most common cause of pericarditis in cattle

Answer 1

The correct answer is hardware disease (traumatic reticuloperitonitis). Cattle ingest wires which then perforate the reticulum and migrate into the pericardium and cause an infection. In small ruminants, Clostridium perfringens will cause pericarditis. In swine, pericarditis may be caused by haemophilus, streptococcus, and Stephanurus edentatus.

Question 2

How many days is the bovine respiratory cycle?

Answer 2

21

Question 3

What is the most common direction of a coxofemoral luxation in cattle?

Answer 3

Cranial and dorsal displacement

Question 4

Is osteochondritis common in cattle?

Answer 4

No. They aren’t even lame.

Question 5

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?

Answer 5

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 6

Tag 10169, a 2.5-year old Guernsey, presents for clinical signs of colic. There is a history of very little feces being passed over the last 24 hours. On rectal exam, a distended structure can be palpated just cranial to the pelvis. The structure feels like a loaf of bread. Additionally, there is a right sided ping heard from the last rib to the pelvis, high up. The rest of the physical was unremarkable. What is your top differential?

Answer 6

The 3 most common causes of colic are intussusception, cecal dilation with or without torsion, and abomasal volvulus. You can quickly rule out the torsion of the omasum and abomasum and the RDA, as the ping would be lower on the right and in front of the last rib, plus you would not have palpated the “loaf of bread” rectally. Cattle with intussusception usually have scant dark blackberry jam-colored feces and on rectal exam, sometimes have a palpable hard and painful mass on the right.

Question 7

What is the etiologic agent of calf diphtheria?

Answer 7

The correct answer is Fusobacterium necrophorum. Clinical signs are seen between 3-18 months of age.

Question 8

lumpy jaw ETx?

Answer 8

Actinomyces bovis

Question 9

wooden tongue EDx?

Answer 9

Actinobacillus lignieresii

Question 10

infectious bovine rhinotracheitis. EDx?

Answer 10

Herpes virus

Question 11

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?

Answer 11

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 12

A 3-year old open beef cow presents as a result of lameness in her right hind limb. Upon physical examination, you notice an ulcerated necrotic lesion in the interdigital space.

What are the DDx?

Answer 12

Bovine viral diarrhea Your Answer

Malignant catarrhal fever

Foot-and-Mouth disease

Interdigital necrobacillosis

Question 13

When do you vaccinate for clostridial diseases?

Answer 13

Blackleg is caused by Clostridium chauvoei, but can also be seen with Cl. septicum or Cl. sordellii (often called malignant edema). Vaccines containing up to 8 different Clostridia are often used. Calves under one year old are most susceptible. On high-risk farms it may be necessary to start vaccination at a younger age or also vaccinate cows to maintain high colostral levels of antibody, and/or to give a booster (second) dose 4 to 8 weeks following the initial dose to calves. Annual revaccination of at least yearlings is also recommended.

Question 14

You are out to examine cattle at a beef ranch and the rancher mentions that there has been investigation regarding a possible E. coli O157:H7 outbreak at a nearby herd. He wants to know what sign(s) infected cows would be most likely to display. What is the best answer?

Answer 14

E. coli O157:H7 is a concern because of its zoonotic potential and not because of pathology seen in cattle as infected animals are typically asymptomatic. The bacteria are spread through fecal-oral transmission, most commonly by contamination of food or water supplies. Recent outbreaks in North America have involved contamination of foods (vegetables such as spinach and lettuce). The major sign seen in humans is hemorrhagic colitis.

Question 15

What are the signs in of birthing in cattle?

Answer 15

• Enlargement of udder
• Peripelvic ligament relaxation
• Enlargement of vulva

NO INCREASE IN BODY TEMPEARTURE!

Question 16

In what time frame does postparturient hemoglobinuria occur in cattle?

Answer 16

It actually only occurs during the first lactational month. It is caused as a result of hypophosphatemia.

Question 17

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?

Answer 17

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 18

A 4 year old Ayrshire cow presents with a two day history of depression, anorexia, fever, conscious proprioceptive deficits, right sided head tilt, and head-pressing. A neurologic exam identified cranial nerve deficits. Particularly, the right ear is drooping, the right eye appears “dropped”, and she is drooling from the right side of her mouth. Where is the lesion?

Answer 18

The correct answer is right side and intracranial. This is evident because the head tilt and cranial nerve deficits are usually on the side of the lesion and all of these are occurring on the same side in this situation. If you have to guess go with ipsilateral to the lesion. This is an intracranial problem since you have conscious proprioceptive deficits, head pressing, and depression.

Question 19

A herdsman is concerned about Johne’s disease affecting his herd. He comes to you and asks what the treatments of choice for the affected cattle are. What is your response?

Answer 19

The correct answer is to cull all cattle that test positive. Johne’s disease in cattle is caused by Mycobacterium avium subsp paratuberculosis affecting the small and large intestine. Clinical signs include emaciation, wasting, and edema, with variable diarrhea. Diagnosis is by serology and identification of the acid fast bacteria. There is no effective treatment for the disease. Positive animals must be culled from the herd.

Question 20

Which of the following hormones would be most effective and economical in raising the amount of milk produced by a dairy cow?

Answer 20

Also called growth hormone, injections of bovine somatotropin (BST) every 14 days can significantly prolong the lactation curve and result in increased milk production.

Question 21

Continued loss of large volumes of saliva in a cow can result in __________

Answer 21

The correct answer is metabolic acidosis. Ruminant saliva has lots of bicarbonate to help neutralize fatty acids being produced in the rumen. Ruminants have about 80 meq/L of bicarbonate in their saliva. Horses, on the other hand, have lots of chloride in their saliva and develop hypochloremic metabolic alkalosis when they lose saliva.

Question 22

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?

Answer 22

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 23

A 6-year old purebred Angus beef cow has chronic diarrhea, weight loss, and ventral edema. On physical exam you note T=102F (38.9 C), HR=80, and RR=20. You find an enlarged left kidney by rectal exam. Laboratory abnormalities include hypoalbuminemia, hyperglobulinemia, proteinuria, and elevated serum creatinine. What is the most likely diagnosis?

Answer 23

In response to a chronic inflammatory (often infectious) process, amyloid can accumulate in the kidneys and result in chronic renal failure, consistent with these clinical signs and laboratory results. Pyelonephritis would have fever and white blood cells in urine ( and also RBCs in some cases), not only protein as was seen in this case.

Question 24

A 3-year old open beef cow presents as a result of lameness in her right hind limb. Upon physical examination, you notice an ulcerated necrotic lesion in the interdigital space. Which of the following is NOT a differential diagnosis?

Answer 24

The correct answer is infectious bovine rhinotracheitis. There are three subtypes of infectious bovine rhinotracheitis identified. BHV-1.1 (Bovine herpes virus) is responsible for respiratory infections. BHV-1.2 may cause genital infections and respiratory disease. BHV-1.3 (reclassified recently and now called BHV 5) has been known to cause neurologic infections. Since most people are not aware of the reclassification, this aspect of the issue is unlikely to be questioned on a board examination. All of the other listed answer choices can cause the lesion described in the question.

Question 25

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?

Answer 25

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 26

A 2-year old Holstein heifer presents for depression and decreased milk production over the previous week. On physical exam, it is noted her posterior shape is “papple” and she is slightly dehydrated. T=100.2 (37.9 C), P=62, R=28. She does not have episcleral injection. Rumen contractions are not present. Xiphoid pain response is negative and you are able to hear a monotone ping in the rumen on the left side from the 11th rib to the hip. On ballottement and rectal exam a large fluid-filled rumen is palpable. Which of the following is the most likely diagnosis?

Answer 26

The correct answer is failure of omasal transport, a form of vagal indigestion, which leads to an accumulation of fluid and some dorsal gas in the rumen, lack of motility, and inappetance. TRP is a common cause of vagal indigestion; the negative grunt test for xiphoid pain is the result of chronicity and formed adhesions that are no longer acutely painful. It is difficult to clinically distinguish between omasal transport failure and pyloric outflow failure, except that the latter usually has more profound acid-base and electrolyte disturbances, and the cow will appear sicker as a result.
Abomasal torsion can be immediately ruled out because there is no abomasal ping on the right. In addition, if it were a right displaced abomasum, the cow would be showing more signs of distress and systemic disease such as episcleral injection and an elevated heart rate. Left displaced abomasum can be ruled out because the ping is monotone (LDA ping is variable in pitch) and the ping extends all the way back to the hip. Further, the large fluid filled rumen is rectally palpable, whereas a cow with LDA would have an empty rumen. Grain overload (rumen acidosis) would have a large fluid filled rumen, but the cow would be very sick with scleral injection and rapid heart rate.

Question 27

While performing a rectal exam on a cow showing teeth grinding, restlessness, kicking at the abdomen, and scant dark blackberry jam feces you are able to palpate a sausage-shaped mass. What is your diagnosis?

Answer 27

The correct answer is intussusception, a cause of colic in cattle. Feces become scant and then become dark red as the bowel mucosa undergoes death. Palpating a painful sausage-shaped mass is classic for an intussusception, which usually occurs in the ileum in adult cows. Although lymphoma or fat necrosis can create the sausage shaped mass, they are less likely and would not have the sudden onset or show the dark feces. Peritonitis may result secondary to the intussusception. Abomasal ulcers result in melena and anemia which can progress to death if not addressed.

Question 28

Which of the following cows is most likely to develop fatty-liver syndrome if daily energy requirements were to increase?

Answer 28

Fat cows are more predisposed to fatty-liver syndrome when they encounter a negative energy balance. Shortly after postpartum, their energy needs increase dramatically with lactation and they mobilize fat stores in such a manner that the liver cannot keep up with the triglycerides coming in. The result is hepatic lipidosis.

Question 29

Which of the following is the most desirable bulk tank milk somatic cell count in cows?

Answer 29

The correct answer is less than 200,000 cells/ml. The goal is to have a SCC of less than 200,000 cells/ml.

Question 30

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?

Answer 30

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 31

Several steers in a feedlot have interdigital lesions as shown in this image. They are lame and the lesion appears to be painful. You diagnose interdigital necrobacillosis or infectious footrot. Which of the following is the most effective feedlot treatment?

Answer 31

One dose of 40 mg/kg florfenicol is reported to be an effective therapy and would be favored by a feedlot because the single treatment would avoid costly repeated handling. The use of chloramphenicol is prohibited in cattle in the USA.

Question 32

It is the middle of winter and this adult Holstein cow in the picture has just presented after developing neurologic signs including ataxia, head-pressing, nystagmus, and star-gazing. There were no significant clinical exam findings besides the neurologic signs described. The owner was questioned about the housing situation this cow was in because this cow is representing 7 other individuals who are similarly affected. The owner said that nothing has changed in the diet and they are fed a complete mixed ration. Additionally, they are provided water with automatic water feeders. Initial blood work is as follows: Sodium 164 mEq/L (normal 132-152), Chloride 115 mEq/L (normal 97-111), Potassium 4.6 mEq/L (normal 3.9-5.8), Calcium 11.9 mg/dl (normal 9.7-12.4) , Glucose 78mg/dl (normal 45-75), and Protein 7.9mg/dl (6.7-7.46). Which of the following is the most likely diagnosis?

Answer 32

The correct answer is salt poisoning. Notice the markedly elevated blood sodium level. A sodium value that high is diagnostic for salt poisoning. If for some reason you are still not sure, you could perform a CSF tap and check the sodium levels and be completely certain. What probably happened to these animals is that the water pipes froze (occurs in northern US with cold winters). As a result, the cows were deprived of water for a certain period of time. During that time, their bodies began to accumulate sodium in the cells of the brain and produce these intracellular proteins to draw water in and maintain normal function. The cows then drink lots of water at the first chance they get, and the hyperosmolar environment in the brain causes water to rush into the cells and destroy them. Ingestion of blue-green algae results in a peracute intoxication which usually results in convulsions, ataxia, bloody diarrhea, and death. Leukoencephalomalacia is a disease which affects horses as a result of ingesting corn infested by the fungus Fusarium moniliforme. Lead poisoning is less likely because the history, clinical signs, and findings are not consistent with exposure to lead.

Question 33

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.

Answer 33

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 34

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?

Answer 34

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 orall

Question 35

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?

Answer 35

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 36

This cow in the picture presents for chemosis and oculonasal mucopurulent discharge. On physical exam, you note her to be sneezing, febrile, and having small white fibrinonecrotic plaques on her conjunctival and nasal mucosa. What is your diagnosis?

Answer 36

The correct answer is infectious bovine rhinotracheitis. The key clinical sign to make this diagnosis is the white fibrinonecrotic plaques. None of the other answer choices cause white fibrinonecrotic plaques.

Question 37

A 1-month old Charolais calf presents as a result of exercise intolerance and collapse. The only abnormality is elevated AST, CK, and LDH. Selenium and vitamin E levels were submitted for analysis and are normal. CSF collected by lumbosacral puncture is normal. What is your most likely diagnosis?

Answer 37

The correct answer is myophosphorylase deficiency. This is a genetic disease that has been identified in Charolais cattle. Affected cattle are born with a deficiency in the enzyme phosphorylase. Your other main differential would have been white muscle disease, but vitamin E and selenium levels are normal. Tetanus would present differently (rigid paralysis), and a brain abscess is highly unlikely as there are no neurological deficits mentioned.

Question 38

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?

Answer 38

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 39

A 7 month old Holstein heifer has presented to you with a history of lameness, fever, and respiratory signs including cough, tachypnea and nasal discharge. The owner is concerned because yesterday several more young animals began to exhibit the same signs and one has died. In addition to the signs already noted on PE, you note swollen joints and tenosynovitis in several animals. You perform a post mortem and find the lungs shown in the image, with multiple abscesses full of pus and caseated material. You suspect Mycoplasma bovis and submit samples for culture. What treatment should you now select based on this presumptive diagnosis?

Answer 39

Tulathromycin was approved in the USA for use in treating respiratory disease caused by M. bovis. Many isolates of M. bovis show resistance to most of the other drugs listed. Since Mycoplasma lack a cell wall, drugs that act on the cell wall such as penicillins and cephalosporins are never the best choice. Other possible good choices are tetracyclines or tilmicosin, but many reports of tilmicosin resistance have appeared in the last few years.

Question 40

Several cows on a farm have developed large very hard masses along the jaw and you have diagnosed Actinomycosis. What management change would you recommend?

Answer 40

The bacteria causing lumpy jaw (Actinomyces bovis) is a normal inhabitant of the cow’s oral cavity or rumen and causes disease when it is able to invade into damaged mucosa, most frequently caused by scabrous or prickly feed.

Question 41

When formulating late gestation anionic diets for dairy cows to help prevent hypocalcemia in the last 2 to 3 weeks prior to calving, what formula is used?

Answer 41

DCAD = (Na + K) - (Cl + S)

DCAD stands for Dietary Cation Anion Difference. Na=sodium, K=potassium, Cl=chloride, and S=sulfur. These are the 4 most important strong ions to be considered. When the diet is optimal the urine pH of Holstein cows should range between 6.2 and 6.8 for cows on the ration.

Question 42

The photo shows a 3-year old dairy cow which has suddenly developed an enlarged abdomen, is acutely down on milk production, and is not eating. She freshened one month ago, and was a high producing cow. On physical exam, you find a large ping on the right side from just behind the last rib to the 10th rib, and note a large amount of fluid in both the right and left sides of the abdomen on ballottement. T=101 F (38.3 C), HR=120, and RR=42. You diagnose abomasal torsion/volvulus and prepare her for surgery. What fluid should she be treated with?

Answer 42

A cow with abomasal torsion is accumulating chloride in the forestomachs, which results in hypochloremia and metabolic alkalosis. This in turn leads to hypokalemia as potassium rushes into cells when all available hydrogen ions leave the cells. The treatment of choice is thus IV saline (154 meq/L Na and 154 meq/L Cl) plus potassium. A good rule of thumb for rate of IV administration of potassium is not to exceed 0.5 meq/Kg /hour. So a 500 Kg cow can receive 250 meq/hr safely (which is 12 liters/hr of the fluid described). Oral fluids will simply add to the fluid-filled rumen.

Question 43

A 3-year old Holstein dairy cow, 3 weeks post partum, is presented with the complaint that she has dropped in milk production over the last several days. You perform a physical exam and the only abnormality you note is a large amount of ketone bodies in the milk and urine. You decide to administer glucose IV and insulin SQ. What else should this cow be administered?

Answer 43

The oral propylene glycol will serve as a precursor for glucose production, and will help with the demands of lactation that are causing increased fat mobilization and ketosis. A fourth treatment that is sometimes used is corticosteroids, as they decrease milk production and increase gluconeogenesis

Question 44

You examine a very ill 4-year old Holstein dairy cow on a large commercial dairy. She freshened one week ago and was producing well, until she was found down and unwilling to rise this morning when you were called. T=103F or 39.4 C, HR=90, and RR=35. The scleral vessels are dark are enlarged, her rumen is fairly empty and the motility is poor, and she appears too weak to rise. Rectal exam reveals an involuting uterus which can be retracted, discharging a brownish red mucoid non-odorous lochia through the vagina. The left rear quarter of her udder is swollen, hot, painful, and discolored (see image), and contains a serum-like secretion with clumps of fibrin in it. What is your diagnosis?

Answer 44

This is a case of severe acute coliform mastitis, and the absorbed endotoxin (LPS) is causing many of the systemic signs observed. The cow needs to be aggressively treated with IV fluids, NSAIDS, and supportive nursing. The gland should be frequently milked out. The use of both intramammary and systemic antimicrobial drugs to which most coliforms are susceptible is still controversial, but is often done in cows in a severe state of illness as in this case. While this cow may have secondary hypocalcemia, treatment with calcium needs to be approached cautiously, as endotoxic animals have very sensitive myocardium and arrest may occur if calcium is given IV. If given, preferred routes of calcium administration would be subcutaneous or oral.

Question 45

You are called one summer day by a local dairy because they have 40 cows down and unable to get up this morning. Several others are weak and staggering. The owner reports that the affected cows are in all stages of lactation. You rush to the farm and examine several cows. They have normal TPRs, but are profoundly weak. When you pull out the tongue to examine the mouth, the tongue stays out (see image). Masseter muscle strength also seems weak. The cows have poor rumen motility and refuse food. The eyes are dilated and pupillary light responses are poor. The ears droop and tail tone is weak. Which disease best fits these clinical signs?

Answer 45

Also known as forage poisoning, botulism usually occurs in groups of animals fed either haylage improperly stored in plastic bags or feed contaminated by an animal carcass and then mixed into the total mixed ration.

Question 46

A beef cow presents for decreased milk production. On physical exam, the cow has a fever of 104.5F. Her urine is yellow, and the dipstick tests are normal. You make a blood smear and see an organism at the margin of the red blood cells. What is your treatment of choice for this animal?

Answer 46

The correct answer is oxytetracycline. The cow has Anaplasmosis, a rickettsial organism that is transmitted by ticks. Infected calves have a low mortality rate, but adult cattle have a 20-50% mortality rate with this disease.

Question 47

You are in a dairy performing pregnancy checks and notice white plaques on the vagina of the 27th cow that you rectal. What is your diagnosis?

Answer 47

The correct answer is infectious pustular vulvovaginitis. This is another clinical manifestation of herpes virus. Clearly, this is not a vaginal prolapse since there is no straining or prolapsed tissue. Squamous cell carcinoma is possible but will most likely present as an ulcerated region or proliferative lesion. Melanoma is rare in cattle and will probably be a black to gray proliferative nodule or nodules if it is seen.

Question 48

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 ?

Answer 48

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 49

A 6-month old calf presents with a head tilt towards the right side and spontaneous horizontal nystagmus with the fast phase directed towards the left side. Ventral strabismus (eye drop) is present on the right side. There is drooping of the right upper eyelid and drooping of the right ear (see image). Which of the following is the best list of differential diagnoses?

Answer 49

The calf’s signs are most consistent with dysfunction of the peripheral vestibular system (although one cannot rule out central vestibular) and facial nerve dysfunction. Middle/inner ear infection or trauma are likely and listeria is a reasonable differential as well. Most of the other choices listed are not typically associated with vestibular signs as described in this case.

Question 50

What do you put in the abdomen after surgery to prevent adhesions?

Answer 50

carboxymethylcellulose

Question 51

What does the papple shape mean?

Answer 51

vagal/rumenal distention

Question 52

You suspect Mycoplasma bovis and submit samples for culture. What treatment should you now select based on this presumptive diagnosis?

Answer 52

Tulathromycin was approved in the USA for use in treating respiratory disease caused by M. bovis. Many isolates of M. bovis show resistance to most of the other drugs listed. Since Mycoplasma lack a cell wall, drugs that act on the cell wall such as penicillins and cephalosporins are never the best choice. Other possible good choices are tetracyclines or tilmicosin, but many reports of tilmicosin resistance have appeared in the last few years.

Question 53

Classical brain histopath lesion with listeria

Answer 53

microabscesses.

Question 54

What valve is most commonly affected with endocarditis in cattle?

Answer 54

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 55

Which immunoglobulin predominates in bovine colostrum?

Answer 55

IgG

Question 56

What is the treatment for tuberculosis in cattle?

Answer 56

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 57

At what age during gestation is a fetus most likely to become persistently infected with the noncytopathic form of bovine viral diarrhea?

Answer 57

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 58

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?

Answer 58

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 59

You are called to a dairy farm in the western United States because several cows are standing in the corral rather than eating with the others. They have been drooling and champing their mouths. The daughter’s horse is also affected. On physical exam of the cows you find their rectal temperatures to be elevated and that their tongues are ulcerated as shown in the photo, but there are no other lesions you can find on the feet or teats. You call the state and federal veterinarians and say that this looks most like a case of

Answer 59

VS occurs as an epidemic about once every 7 to 10 years in the western US. It appears to be spread by insect vectors and then spreads by contact and fomites from cow to cow once clinical disease occurs. Horses can also be affected by this virus.

Question 60

Which type of urolith occurs most commonly in western U.S. range cattle grazing mature grasses as shown in the photo?

Question 61

Which of the following is NOT considered an environmental mastitis organism?

Answer 61

The correct answer is Streptococcus agalactiae. It is involved with contagious mastitis, and is not environmental. The others are all considered to be environmental causes of mastitis. Pseudomonas aeruginosa, E. coli, Enterobacter aerogenes, Arcanobacterium pyogenes, and Proteus spp. are all causes of environmental mastitis.

Question 62

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?

Answer 62

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 63

Mucosal disease, or alternatively, chronic Bovine Virus Diarrhea (BVD) occurs in cattle when:

Answer 63

This is the correct answer because it describes the current understanding of the pathogenesis of both mucosal disease and chronic BVD.
A 5-month old calf is infected with CPE biotype of BVD virus and then superinfected with a nonCPE biotype of BVD virus is incorrect because it does not say that there was persistent fetal infection; also, the order of the superinfection is the reverse of what causes mucosal disease or chronic BVD.
A 5-month old calf which was persistently infected with the nonCPE biotype of BVD virus as a fetus forms antigen-antibody complexes which cause a fatal immune-mediated disorder is incorrect because this is not the mechanism by which mucosal disease or chronic BVD occur.
All other answer choices are incorrect because they each describe one of the acute clinical syndromes from primary infection, rather than either mucosal disease or chronic BVD.

Question 64

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?

Answer 64

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.