Bovine II Flashcards
A three-week old Jersey calf presents due to an inability to walk. On physical exam, there are no signs of trauma and it is noted that the hocks will not flex due to continuous gastrocnemius tension. There were no other abnormal physical exam findings. What is your primary differential?
- Septic hocks
- Bilateral gastrocnemius rupture
- Spastic paresis
- Tetanus
Answer: Spastic paresis
Explanation
The correct answer is spastic paresis (aka Elso heel). This is a hereditary disease which produces a continuous stiffness of the hocks. There could be bilateral or unilateral involvement. It is a recessive disease; therefore, affected animals should not be bred. Treatment involves a tibial neurectomy or gastrocnemius tenectomy.
Given these signals and clinical signs, spastic paresis should be high on your differential list. Sepsis is highly unlikely because there are no other signs of systemic disease. You would see the opposite clinical signs with a gastrocnemius rupture.
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?
- Salmonella dublin
- E. coli septicemia
- Malignant catarrhal fever (MCF)
- Bovine virus diarrhea (BVD)
- Mannheimia hemolytica bronchopneumonia
Answer: Salmonella dublin
Explanation
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.
***PowerLecture: Diarrhea Part 1
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?
- Cardiomyopathy
- Valvular endocarditis
- Traumatic pericarditis
- Brisket disease
- Ventricular septal defect
Answer: Traumatic pericarditis
Explanation
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.
***PowerLecture: Traumatic Reticuloperitonitis
The majority of abortions in cattle infected with Neospora occur in the early second trimester. You have diagnosed neospora abortion on a California dairy and the owner asks you where it comes from?
- Dogs (and coyotes) are the definitive hosts of Neospora caninum
- Cats defecate in the feed and spread the oocysts.
- The disease is venereally transmitted, so all bulls must be tested.
- Pigeons are the source. Shoot and trap all pigeons.
Answer: Dogs (and coyotes) are the definitive hosts of Neospora caninum
Explanation
Neospora abortions usually occur around 4-6 months, but can occur throughout gestation. Calves with neurologic deficits may also result. Dogs ingest infected tissues from fetus or placenta and pass oocysts in feces, which are ingested by cows.
Other causes of abortion tend to occur later in gestation (such as Brucella, Listeria, and leptospirosis). A confirmed diagnosis of N caninum is based on histologic lesions which are found in the brain (and also other organs) and consist of scattered foci of nonsuppurative cellular infiltrates with occasional foci of necrosis.
A 5 month-old Angus calf in a beef herd in northern California has died and another is sick with lethargy and coughing. The herd owner has also seen stiff calves that had difficulty walking and died shortly after being observed. You perform a post-mortem on the dead animal and find pale areas and fibrosis in the cardiac muscles (see image); therefore, a diagnosis of white muscle disease is made. You plan to take blood samples to test for what?
- Clostridial infection of the heart
- Genetic trait linked to myocardiopathy in calves
- Selenium deficiency
- Copper deficiency
- Vitamin A deficiency
Answer: Selenium deficiency
Explanation
Nutritional myodegeneration (white muscle disease) is associated with low dietary selenium levels and compounded by low dietary vitamin E. Unsupplemented cattle grazing soils of volcanic origin are at high risk, and calves born in these herds may show skeletal or cardiac muscle syndromes. Measurement of whole blood selenium in 10 animals will indicate if the herd needs supplementation with selenium.
A 2-year old Brown Swiss with an abomasal torsion is likely to have which electrolyte abnormalities?
- Hyperglycemia, hypochloremia, and hyperkalemia
- Hyperchloremia, hypokalemia and metabolic acidosis
- Paradoxic aciduria, hypochloremia, and hyperkalemia
- Hyperkalemia, hypocalcemia, and metabolic alkalosis
- Hypochloremia, metabolic alkalosis, and hypokalemia
Answer: Hypochloremia, metabolic alkalosis, and hypokalemia
Explanation
The correct answer is hypochloremia, metabolic alkalosis, and hypokalemia. As a result of torsion, affected animals sequester HCl in the abomasum, get hypochloremia and metabolic alkalosis. Additionally, animals become dehydrated and try to maintain adequate blood pressure by conserving sodium through renal mechanisms. Because there is an alkalosis, potassium is sequestered even more than usual in cells leading to hypokalemia. Normally the kidney excretes some potassium because of the need to maintain an equal number of anions and cations in the urine. But when there is insufficient potassium available, in order to reabsorb sodium to maintain blood pressure, hydrogen ions are excreted rather than potassium. This results in acidic urine at the same time as metabolic alkalosis, a condition known as paradoxic aciduria.
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?
- Cardiac arrhythmia
- Bone marrow suppression
- Liver failure
- CNS signs
- Cyanide toxicosis
Answer: Bone marrow suppression
Explanation
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.
Regarding normal reproductive physiology, the cow differs from the sow, the mare, the ewe, and the nanny/doe in which of the following ways?
- Only the cow is normally in estrus for fewer than 5 days
- Only the cow is a seasonal ovulator
- Only the cow has an epithelio-chorial placenta
- Only the cow ovulates after the end of estrus
- Only the cow normally ovulates a single oocyte per cycle
- Only the cow does not have an epithelio-chorial placenta
Answer: Only the cow ovulates after the end of estrus
Explanation
An unusual feature of bovine reproductive physiology is the fact that the cow ovulates after she goes “out” of estrus. The practical implication of this is that one can successfully breed by artificial insemination later, relative to estrus.
The mare, the ewe, and the nanny/doe are all seasonal breeders, but generally, the cow is not.
All the animal species listed in the question have an epithelio-chorial placenta.
Although twin births do occur in a minority of cows, the cow normally ovulates a single oocyte per cycle, as does the mare. Sheep and goats have been selected for fecundity, with the result that multiple ovulations/cycle are the rule, rather than the exception. Litter-bearing pigs ovulate large numbers of oocytes per estrous cycle.
The sheep and goat are in estrus for only 1.5-3 days; the pig is similar. Only the mare, of the species listed, is physiologically in estrus for 5 days or more.
There are 5 dead cows and 3 dead birds next to a pond. The cows have no other medical history. What is your most likely diagnosis?
- Selenium toxicity
- Moldy sweet potato toxicity
- Bracken fern poisoning
- Blue green algae toxicity
- Sudan grass
Answer: Blue green algae toxicity
Explanation
The correct answer is blue green algae toxicity. The fact that they died right next to the pond and the species affected are key factors. Unfortunately, vague presentations are likely to be common on board examinations.
Any living animals would have miosis, ptyalism, bradycardia, and diarrhea as potential clinical signs. The algae produces toxins that are absorbed through mucous membranes and cause a post-synaptic depolarizing block.
Affected animals can die within minutes of drinking the water. As little as 1.5L can kill a cow.
You have diagnosed interdigital necrobacillosis (infectious footrot) in a herd of 300 female beef cattle. It is a rainy summer, and the animals have been confined for artificial insemination in muddy conditions. In addition to treating the obviously lame cattle with oxytetracycline, which of the following recommendations should be made to effectively aid in controlling and preventing the spread of this problem?
- Spray the entire pasture with 2% copper sulfate to eradicate the organism
- Vaccinate herd against Dichelobacter nodosus
- Test all animals and remove Fusobacterium necrophorum carriers
- Put several tons of crushed stones in one area for the cattle to stand on
- Either disperse the group or provide a dry area on which to stand
Answer: Either disperse the group or provide a dry area on which to stand
Explanation
The high density of animals, wet muddy conditions, combined with interdigital trauma from rocks, can be the major culprits. Break that cycle if possible.
Bovine spongiform encephalopathy (BSE or mad cow disease) is not only a health concern for the management of cattle but also has potential public health implications if bovine nervous tissue from infected cows is consumed by humans. BSE has been implicated in a condition that mimics which of the following human diseases?
- Charcot-Marie-Tooth disease
- Churg-Strauss syndrome
- Cockayne syndrome
- Crigler-Najjar syndrome
- Creutzfeldt-Jakob disease
- Crohn’s disease
Answer: Creutzfeldt-Jakob disease
Explanation
BSE is a transmissible spongiform encephalopathy suspected to be caused by a prion.
True Creutzfeldt-Jakob disease (CJD) is a rare disorder that can occur due to a genetic mutation or may occur sporadically. Patients may experience psychiatric symptoms such as depression or a schizophrenia-like psychosis. Unusual sensory symptoms may also occur. Neurological signs progress to difficulty walking and involuntary movements, and, by the time of death, patients become completely immobile and mute.
Variant Creutzfeldt-Jakob disease (vCJD) typically affects younger people and has been strongly linked to exposure, probably through food, to cattle BSE.
You DO NOT need to know about the other human diseases listed here but for your information:
Crohn’s disease is a form of inflammatory bowel disease involving chronic inflammation of any part of the gastrointestinal tract.
Crigler-Najjar syndrome is a rare autosomal recessive disorder of bilirubin metabolism.
Churg-Strauss syndrome is a type of systemic vasculitis.
Charcot-Marie-Tooth disease refers to a group of disorders, usually passed on genetically that are from disorders of myelin or nerves and cause weakness.
Cockayne syndrome is an inherited disorder of DNA repair that causes individuals to be sensitive to ultraviolet light.
You are examining a group of 20 yearling beef heifers in a late summer in Alberta, Canada that has been cooler and wetter than normal. The heifers have been experiencing poor growth and diarrhea. The farmer reports that the cows have developed a frequent, non-productive cough after exertion in the past week. You examine the cows and find their vital parameters to be within normal limits with the exception of several mildly tachypneic cows. There is no ocular or nasal discharge seen. You auscult occasional crackles in many of the cows. Fecal examination reveals Dictyocaulus viviparus L3 in three of six samples. You treat the cows with ivermectin and see cessation of coughing and diarrhea within a few days. Which of the following would be the best way to prevent this problem next year now that there is a known risk?
- Control of snails
- Persistent use of anthelmintics 2 to 3 times during the grazing season
- Control of ticks
- Control of earthworms
- Injectable vaccine administered 4 weeks before the grazing season
Answer: Persistent use of anthelmintics 2 to 3 times during the grazing season
Explanation
Based on the presentation and diagnostic findings, this is a case of Dictyocaulus viviparus, the bovine lungworm and cause of verminous bronchitis. Although the worm is more common in Europe, cases can be seen worldwide including in North America, particularly when weather conditions permit (cooler, moist summers).
Dictyocaulus often affects younger cattle more severely. Signs include cough and frequently tachypnea. The diagnosis is frequently suggested by the seasonal incidence although confirmation with fecal examination (Baermann) is important to achieve a definitive diagnosis. Treatment with an anthelmintic of clinically affected animals is usually effective.
Dictyocaulus has a direct life cycle and does not require a snail, earthworm, or tick for transmission. There are 2 main methods of prevention. A strategic anthelmintic program entails administration of an anthelmintic such as ivermectin at 3, 8, and 13 weeks post-turnout. There are approximately 28 days of residual activity against lungworm. Vaccination is used in some areas (mainly Europe) and involves an attenuated oral vaccine of 1,000 irradiated L3 Dictyocaulus viviparous at 6 and 2 weeks pre-turnout.
The image shows a radiograph of a valuable three-week old dairy calf which is very lame. What is the correct diagnosis?
- Arthritis
- Fractured distal third metacarpal
- Osteosarcoma
- Fescue foot
- Septic arthritis and osteomyelitis
Answer: Septic arthritis and osteomyelitis
Explanation
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.
Yellow arrows: There is severe soft tissue swelling circumferentially
Red circle: Severe lysis of the proximal interphalangeal joint of the lateral digit
Blue arrows: Marked osseous proliferation.
Radiographs provided by Adrien Hespel, DVM, MS, DACVR and University of Tennessee College of Veterinary
Medicine
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?
- Pseudorabies
- Rabies
- Polioencephalomalacia
- Salt poisoning
- Hypomagnesemia
Answer: Pseudorabies
Explanation
The correct answer is 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.
It is March in the foothills, the grass is 2 inches high, and the oak trees are in early leaf stage. The calves are 4-5 months old, grazing alongside their dams. There are some 12,000 calves scattered around the county. A huge sudden spring snowstorm deposits 10 inches of wet snow, completely covering the grass and causing many oak branches to break and fall to the ground. Ranchers remember that when this last happened 20 years ago, many of their calves died or became very sick from eating nothing but oak leaves and buds for a week. What can you recommend to them now to avoid a repeat of such a scenario?
- Administer IV fluids to all calves to flush out the oak toxins
- Quickly spread hay out in the hills where the calves can eat it
- No action is necessary, the calves will simply suckle their dams and avoid the oak
- Catch calves and administer calcium hydroxide to each one daily
- Apply for disaster aid
Answer: Quickly spread hay out in the hills where the calves can eat it
Explanation
The best way to prevent oak (Quercus) toxicity is to allow the animals to fill up on hay, since the grass is covered by snow. None of the other solutions are practical (or possible).
Oak tannins are hydrolyzed in the rumen to toxic gallic acid, pyrogallol. Cattle can normally eat some oak and handle the tannins, but when the diet consists of mainly oak the high levels of tannins disrupt the Gl mucosa, and the gallic acid and pyrogallols destroy renal tubules. Some hydrolyzed tannins are absorbed and bound to plasma proteins and endothelial proteins, leading to vascular damage and fluid and blood loss from vessels, resulting in edema.
Ruminants are more susceptible than horses because of the hydrolysis of gallotannins in the rumen.
Several 2- to 4-year old cows in a herd have been losing weight and suffering with chronic watery diarrhea for the past eight months. Which of the following is a good differential?
- Rotavirus
- Pasteurella multocida
- Enteropathogenic E. coli
- Mycobacterium avium subsp paratuberculosis
- Trueperella pyogenes (formerly Arcanobacterium pyogenes)
Answer: Mycobacterium avium subsp paratuberculosis
Explanation
The correct answer is Mycobacterium avium paratuberculosis (Johne’s disease). This disease is known to affect cattle, goats, and sheep, as well as many species of exotic hoofstock.
Infection usually occurs when they are young, but clinical signs do not show up until the animals are stressed. Clinical signs are essentially diarrhea and weight loss due to hypoalbulinemia. The other choices are poor in that they don’t result in a herd problem of weight loss and diarrhea in adult cattle.
For the PowerLecture” on this topic, view
• Paratuberculosis - Johne’s Disease (8:50).
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?
- Listeriosis
- Organophosphate toxicity
- Botulism
- Milk fever
- Anaplasmosis
Answer: Botulism
Explanation
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.
A 3-week old Holstein calf was born unable to bear weight on its pelvic limbs and was often observed dog-sitting. Now, 3 weeks old, the calf is unable to bear weight on the right hindleg (see image). Radiographs show no bony abnormalities. Which of the following would likely prevent this problem in the future?
- Delivery by Cesarean section
- Supplement cows with thiamine
- Vaccinate cows against bovine viral diarrhea virus
- Remove all lupine from the pasture
Answer: Delivery by Cesarean section
Explanation
The description and appearance are most consistent with femoral nerve paralysis. This typically occurs due to excessive traction of oversized calves in anterior longitudinal presentation during calving. Rotation of the calf by 45 degrees into a diagonal orientation to align the widest dimension of the calf’s hips with the widest dimension of the maternal pelvis may assist delivery in some cases. This problem could have been avoided by Caesarean.
The femoral nerve supplies the quadriceps femoris muscle and injury results in rapid and severe atrophy and the inability to extend the stifle joint and bear weight on that leg. Bilateral femoral paralysis results in the inability to stand. Fractures of long bones following dystocia are rare but can occur. Such fractures can be detected by careful clinical examination and radiography.
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?
- Otitis media/interna, middle ear trauma, listeriosis
- Bluetongue, bovine viral diarrhea virus, bovine spongiform encephalopathy
- Polioencephalomalacia, congenital brain tumor, thromboembolic meningoencephalitis
- Rabies, pseudorabies, cerebellar hypoplasia
Answer: Otitis media/interna, middle ear trauma, listeriosis
Explanation
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.
It is November and one of a group of 6 to 7-month old calves that entered a feedlot 50 days ago is sick. He has been observed coughing and open-mouth breathing with his head extended, and has a nasal discharge. You examine him and find his vitals to be T=105F 40.6 C, RR=70 (27-36 breaths/min), HR= 100 (60-70 beats/min). His breath is necrotic-smelling, and his larynx is swollen and painful on palpation (see image). There is inspiratory dyspnea and stertor. Based on the history and clinical signs you diagnose necrotic laryngitis (calf diphtheria), believed to be initiated by Histophilus somni, after which Fusobacterium necrophorum proliferates where the mucosa is damaged. This causes necrosis of the laryngeal cartilages. Knowing that the disease is commonly fatal, you elect to treat aggressively. Which of the following would be the best course of therapy?
- Dexamethasone
- Chloramphenicol
- IV Tetracycline followed by SC long acting tetracycline, plus NSAIDS
- Topical sprays containing iodine
- NSAIDS
Answer: IV Tetracycline followed by SC long acting tetracycline, plus NSAIDS
Explanation
The laryngeal cartilages (particularly the arytenoids) can become necrotic (see image), toxemia and bacteremia can develop, and death can ensue. Treatment must be aggressive. Start with a high blood level by giving IV tetracycline, then follow up with long acting tetracycline. Repeat as needed. Penicillin is also a good choice against Fusobacterium necrophorum, but it is more difficult to achieve high levels long-term using penicillin than it is with tetracycline. When edema, inflammation, and dyspnea are very severe, a tracheostomy may be needed, and a dose of corticosteroids may help shrink the swollen larynx. NSAIDS are also indicated. Good nursing care is also essential to recovery.
Chloramphenicol cannot legally be used in animals intended for meat or milk in the USA. Dexamethasone could be used in conjunction with antimicrobials but not alone against Calf Diphtheria. Sprays would not cure this calf.
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?
- Grain overload (lactic acidosis)
- Fatty liver
- Paratuberculosis (Johne’s disease)
- Ostertagiasis
- Salmonellosis
Answer: Paratuberculosis (Johne’s disease)
Explanation
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.
***PowerLecture: Paratuberculosis - Johne’s Disease
A beef steer in a feedlot has moderate chronic bloat, and is eating poorly and losing weight (see image). He was treated a month ago for bovine respiratory disease complex with antimicrobials given for 3 days. You examine him and find a temp=104F (100- 102.6F) (40 C), HR=95/min (60-70), RR=64/min (37-36), and the rumen is gas-filled and has only weak motility. When you pass a stomach tube, the gas is readily removed from the rumen. The lung sounds are harsh ventrally on inspiration and expiration, with some crackles and wheezes also auscultable. On percussion, the ventral thorax is dull. The steer coughs several times while being examined. What is your diagnosis?
- Bovine respiratory syncytial virus pneumonia
- Frothy bloat
- Type 2 vagal indigestion
- Free gas bloat secondary to chronic bronchopneumonia
- Acute bovine pulmonary edema and emphysema
Answer: Free gas bloat secondary to chronic bronchopneumonia
Explanation
Cattle have relatively poor collateral ventilation (as compared to a horse for example) so they tend to get pulmonary consolidation with chronic bronchopneumonia. The inflammation and enlarged lymph nodes associated with chronic infection of the lungs can affect the vagus nerve as it passes through the chest, resulting in type 1 vagal indigestion, or free gas bloat.
Type 2 vagal indigestion is failure of omasal transport and appears as an enlarged fluid-filled rumen. It is most often associated with traumatic reticuloperitonitis. Bovine respiratory syncytial virus pneumonia tends to occur in younger calves and be much more acute and with different auscultation findings than described here. The signs and physical exam do not fit either frothy bloat or acute bovine pulmonary emphysema.
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?
- Salt poisoning
- Blue-green algae toxicosis
- Lead poisoning
- Leukoencephalomalacia
Answer: Salt poisoning
Explanation
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.
A dairy farmer asks you to perform a post mortem exam on a mature Holstein which died suddenly last night. You find the peritoneal cavity full of rumen contents and a perforated ulcer through a rumen pillar (see photo showing rumen mucosa), as well as other ulcers in the rumen mucosa. Based on these findings, what is the correct diagnosis?
- The ulcer inducing bacteria Helicobacter pylori
- Rumen acidosis with ulceration
- Chronic stress induced ulcers
- Mycotic rumenitis from moldy feed components
- Acid reflux from the abomasum into the rumen
Answer: Rumen acidosis with ulceration
Explanation
Feeding high concentrate levels or suddenly changing the amount of concentrate fed can result in a drop in rumen pH below 5.5, ulcers and even perforation. Introducing concentrate slowly and feeding buffers such as sodium bicarbonate can help minimize these problems in high-producing dairy cattle.
