These are my less organized study notes for the NAVLE. Feel free to finish organizing them for yourselves if you have th...
NAVLE Notes General Notes from Questions
Roundworms in small animals are Toxocara species, which are ascarid nematodes. Transmammary and transplacental transfer in dogs, transmammary transfer in cats. Treated with Fendbendazole and Pyrantel every 2 -3 weeks until patient is 4 months old. o Toxocara canis is the most common cause of cough in puppies. o Will cause visceral larval migrans when ingested by humans. Commonly affects eyes of children. o Ivermectin will kill roundworms (nematodes), although this is not the treatment of choice in small animals. o Thelazia are roundworms that affect the ocular tissues. Transmitted by Diptera & Musca flies. Trichuris vulpis is the major whipworm of small animals. Eggs have symmetrically bipolar plugs. Inhabit cecum and colon. Treat with Fenbendazole over a long period.
o Ancylostoma, the canine hookworm, will cause cutaneous larval migrans in humans. o Can infect dogs in utero, via nursing, or by piercing the skin (usually the feet). Tapeworms such as Dipylidium caninum & Taenia taeniaeformis are treated with Praziquantel. o Fleas are the intermediate hosts of Dipylidium caninum. Giardia is a protozoal parasite is treated with fenbendazole or metronidazole.
o o Cannot be seen on fecal sedimentation. Toxoplasma gondii is a protozoan parasite that commonly affects cats. A large percentage of cats are sereopositive but do not shed oocysts. o Infected cats usually only shed oocysts for 1 – 2 weeks when initially affected. o Diagnose active infection with paired titers 1 – 2 weeks apart. o Oocysts take a couple of days to sporulate and become infective, so cleaning the litter box daily reduces the risk of infection for humans. o Treat with Clindamycin. Capillaria aerophilia is a respiratory roundworm. Eggs look similar to Trichuris but are smaller with asymmetrical plugs.
The most common lung worm in cattle is Dictyocaulus viviparous Hydatid cyst disease is caused by the tapeworm Echinococcus granulosus and is fatal in humans. Hypoderma bovis and Hypoderma lineatum start by burrowing into the skin of cows. L1s migrate to the spinal canal or esophagus. The L3s encyst in the subcutaneous tissue of the back. The cysts have breathing holes. Eventually the L3s burst through the subcutaneous tissue on the back. Oxyuris equi are pinworms that affect the perineal region of horses. They cause pruritus and subsequent alopecia in the tail-head region. o Diagnose with a scotch tape test. Gasterophilus (horse bots) typically lay their yellow eggs on the medial aspect of forelimb cannon bones. Habronema is a stomach worm that can cause granulomatous skin lesions with calcified larvae inside. Eggs are ingested by houseflies which are swallowed by horses. Strongylus vulgaris is a nematode (roundworm) that can cause cranial mesenteric artery thrombosis in horses. This can cause acute death. Taenia solium is the pork tapeworm. Ingestion by humans can cause cysticercosis (larval infection). o In humans, the larvae develop into adults. The infection is then called taeniasis. Metastrongylus lung worms affect pigs and require earthworms as an intermediate host. Parascaris equorum cause respiratory signs and GI signs in horses. Piperazine treatment can cause rapid death of ascarids in horses, which can cause colic. Guillian-Barre syndrome in humans is associated with Campylobacter jejuni. Aelurostrongylus abstrusus is the feline lungworm. Treat with ivermectin or fenbendazole. Deep skin mites are Demodex. Superficial skin mites are Sarcoptes. Listeriosis (Listeria monocytogenes) is the most common CNS infection in ruminants. Causes neurologic signs and cranial nerve signs and is treated with tetracyclines or penicillin. o Associated with feeding acidic silage and causes brain microabscesses. o Diagnose with a CSF tap showing mononuclear pleocytosis. Thromboembolic meningoencephalitis has a neutrophilic pleocytosis. o Listeria monocytogenes can grow in the refrigerator and cause CNS signs in humans. Meningitis causes elevated CSF protein and CSF neutrophilia. Polioencephalomalacia does not cause cranial nerve signs. Treat with thiamine. o Can be caused by too much grain feeding; this results in thiaminase-producing bacteria. A granulosa-thecal cell tumor will cause an enlarged cystic affected ovary and a shrunken contralateral ovary. o This is the most common ovarian tumor in horses.
o Can cause aggression in mares. Most common intranasal tumor in dogs is adenocarcinoma and in cats is lymphosarcoma. Aural hematomas in pigs are commonly due to bites from penmates and violent head shaking (due to parasites or debris in ears). Aspergillus is the most commonly identified fungal pathogen in guttural pouch mycosis. o Cranial nerves VII, IX, X, XI, & XII travel through the guttural pouch. Damage to these nerves can result in dysphagia. o Guttural pouch also contains carotid arteries and cranial sympathetic trunk. Escherichia coli is the most common bacterial infection associated with septicemia in foals. o E. coli is a gram negative rod. Myxedema, an increased amount of mucin and other ground substances in the dermis, can be a marker for hypothyroidism. Nutritional encephalomalacia in chicks is due to Vitamin E deficiency. The most common cause of sinusitis in a horse is a tooth root abscess, most commonly in the first molar teeth. The most common congenital cardiac abnormality in the horse is a ventricular septal defect. Skin fragility syndrome in cats is commonly associated with poorly regulated diabetes mellitus due to hyperadrenocorticism Non-enveloped viruses survive longer in the environment. A classic finding for upper GI obstruction is hypochloremic metabolic alkalosis. Perivascularization of Doxorubicin causes severe and irreversible tissue sloughing. If this occurs, place a cold compress to contain the spread of the drug. Doxorubin can also cause cardiotoxicity in dogs and renal toxicity in cats. o Cisplatin causes fatal pulmonary edema of cats (Cis splats cats). o L-asparaginase is used to treat lymphomas and can cause anaphylaxis. Normal cells can make asparaginase; lymphoma cells cannot. Lasparaginase destroys the body’s asparagine. o Lomustine can cause hepatotoxicity. o Vincristine can cause paralytic ileus. o Cyclophosphamide can cause cystitis. o Adriamycin can cause cardiotoxicity. o Tyrosine kinase inhibitors such as Toceranib are used for high-grade mast cell tumors after resection. Treat mast cell tumors with diphenhydramine, famotidine, vinblastine, & prednisone. Eyelid lacerations in horses are treated with saline lavage, tetanus immunization, phenylbutazone, and at least a 2 layer closure. A cat with a history of penetrating ocular trauma and susbsequent blind eyes is suspicious for feline traumatic sarcoma.
o Very malignant, will develop phthisis bulbi (shrunken eye), and treat with enucleation. The cutoff for differing mammary tumor prognoses is 3 cm in dogs & 2 cm in cats. o Mammary tumors more frequently develop in caudal glands. Black widow spider bites cause muscle spasms, muscle rigidity, and pain. Ingestion of Stargazer lillies can cause acute renal failure in cats. Anterior uveitis is the most common cause of cataracts in cats. Clinical signs include hyphema and keratic precipitates. o Treat idiopathic anterior uveitis with systemic prednisone and carprofen as well as topical dexamethasone and atropine. Don’t use topical antibiotics; there are no bacteria. The cornea has the most refracting power in the eye. Feline herpes virus will cause ocular ulcers and commonly cause systemic disease. o Herpes virus is the only cause of corneal ulcers in cats, although corneal ulcers can become secondarily infected with bacteria. o 80 – 100% of affected cats become carriers. Feline calicivirus is the only respiratory virus to cause oral ulcerations. Also causes systemic disease and skin ulcers. o Treat with clindamycin for associated bacterial infections and sucralfate to coat ulcers. Feline herpes virus causes conjunctivitis and dendritic ocular ulcers. For alopecia X (alopecia of unknown cause), castration is treatment of choice. Also try melatonin supplementation. o Consider alopecia X if skin cytology, chemistry panel, thyroid panel, and ACTH stimulation are normal. Mycoplasma gallisepticum causes severe respiratory signs in turkeys and milder respiratory signs in chickens. o Histomonas meleagridis causes fatal necrosis of the liver and di in turkeys, but is less pathogenic in chickens. Proliferative enteritis in swine is caused by Lawsonia intracellularis. Prevent via a vaccine. Treat with tylosin in water or feed. o Lawsonia intracellularis causes proliferative ileitis in hamsters, which causes severe diarrhea. Remember, a Na:K ratio < 23 is a hallmark of hypoadrenocorticism. Morphine will release histamine; avoid in mast cell tumors. o Mast cell tumors can cause local inflammation. The most common cause of glaucoma (increased intraocular pressure) is decreased outflow of aqueous humor. o Acute glaucoma causes episcleral injection. corneal edema, and pain. o Chronic glaucoma causes buphthalmos (enlarged globe). o Glaucoma does not cause strabismus.
o Primary glaucoma in one eye will typically cause glaucoma in the other eye in 6 – 12 months. Primary glaucoma is most common in female spayed Cocker Spaniels. Botulism (Clostridulum botulinum) blocks the release of acetylcholine from the neuromuscular junction, resulting in flaccid paralysis. Can affect cranial nerves. o Clostridium tetani causes muscle stiffness. o Tick paralysis has an ascending symmetrical paralysis and does not cause cranial nerve involvement. o Coonhound Paralysis (Idiopathic polyradiculoneuritis) is usually seen after a raccoon bite. Causes paralysis and facial / laryngeal paralysis. May cause diffuse hyperesthesia. Botulism causes dyspnea, mydriasis, & tongue hanging out. Does not cause proprioceptive deficits. Dogs do not have a transmissible spongiform encephalopathy. Tick paralysis does not involve cranial nerves. Mycobacterium species are acid-fast rods. Idiopathic polyradiculoneuritis (Coonhound Paralysis) is an ascending paralysis normally associated with raccoon exposure. Unknown etiology and animals usually spontaneously recover fully within several months. A positive scooch test (xiphoid pain) in cows is indicative of traumatic reticuloperitonitis. The most important treatment for severe acute blood loss is whole blood transfusions. Aspiration pneumonia causes an alveolar pattern mostly involving the right cranial and middle lung lobe. o Seen cranioventrally on radiographs. Anhidrosis is the inability to sweat. Commonly occurs in horses in hot humid climates. Canine esophagus is entirely striated muscle. o Feline esophagus is 2/3 striated then 1/3 smooth muscle. Mycobacterium bovis is the disease of most concern from drinking unpasteurized cow milk. o Brucella melitensis can be acquired in humans via raw goat milk. Sympathetic innervation to the bladder is provided by the hypogastric nerve. o Parasympathetic innervation to the bladder is provided by the pelvic nerve. o Somatic innervation to the external urethral sphincter is provided by the pudendal nerve. The ideal incision site for a foreign body gastrotomy is halfway between the greater and lesser curvature of the stomach. Cat scratch disease is caused by Bartonella henselae. Spread between cats by fleas and spread to humans via scratches and bites. Results in fever and lymphadenopathy. o Treat with doxycycline. Swayback & enzootic ataxia in sheep and goats is caused by copper deficiency. Positive predictive value is proportion of test-positive animals that are disease-positive.
o Negative predictive value is proportion of test-negative animals that are diseasenegative. o Sensitivity is the proportion of disease-positive animals that test positive. o Specificity is the proportion of disease-negative animals that are test-negative. Rain scald, or dermatophilosis is caused by the bacteria Dermatophilus congolensis. This is a gram positive, facultative anaerobic, branching (railroad tracks) cocci bacteria. o Causes paintbrush lesions on the dorsum and pasterns. o Treat by keeping area clean and dry and penicillins if severe. Superficial bacterial skin infections require at least 3 weeks of antibiotics. T3 is the active thyroid hormone. o Diagnose hypothyroidism in dogs with free T4 by equilibrium dialysis. Most dogs get pyometra during diestrus. This is because progesterone is active during this time. It decreases myometrial activity and leukocyte response while promoting endometrial growth. o Most common cause of small animal pyometra is E. coli. This occurs via vaginal ascension. Allowing to be mounted is the major sign of estrus in a cow. The fast phase of nystagmus is usually away from the lesion. Cervical vertebral malformation affects young horses and cause symmetrical signs of ataxia, normally worse in the hindlimbs. Treated with surgery. o Another differential for these signs is Equine Degenerative Myeloencephalopathy. No definitive test but is associated with low vitamin E levels. Equine protozoal myeloencephalitis is caused by Sarcocystis neurona. Causes asymmetrical clinical signs of ataxia. Treated with TMS and Pyremethamine or Ponazuril. o Diagnose with immunoblot testing of CSF for antibodies to Sarcocystis neurona. Sarcosystis cruzí’s definitive host is the dog. o Sarcosystis hominis has a cat as the definitive host. The equine viral encephalitis viruses cause ataxia, fever, and mental depression. Spread by mosquitoes. Supportive treatment. 0.9% NaCl is an acidifying fluid. Mannitol is an osmotic diuretic. Furosemide is a loop diuretic. Hyperglycemia in a stressed cat without glucosuria is strongly suggestive of a stressinduced hyperglycemia. The most common source of Campylobacter infections in humans in undercooked chicken. o The most common infectious cause of sheep abortion is Campylobacter. Campylobacter jejuni is shown on a fecal smear as gull-shaped organisms. o Causes mucoid diarrhea in puppies. Mast cell tumors in horses are benign.
o Young Siamese cats with the histiocytic subtype of mast cells tumors will usually have the tumors spontaneously regress. o Cutaneous mast cell tumors in cats are most commonly on the head. They rarely metastasize and are not graded. Ketamine has been associated with seizures in epileptic dogs. Bracken fern contains glycoside and thiaminase, which leads to a thiamin deficiency. This causes convulsions, opisthotonus, and death. o Also causes bone marrow suppression. Abomasal ulcers and associated peritonitis have a grave ( 4.5 g/dL, total nucleated count > 25,000/uL, & polymorphonuclear count > 20,000/uL. Ideal treatment for low plasma proteins and GI disease is IV plasma. Electrical cord bites and trauma commonly cause oral ulcerations and burns as well as non-cardiogenic pulmonary edema. The most common complication of intestinal resection and anastomosis surgery is leakage at the surgery site. o This usually occurs 3 – 5 days post-operatively and can cause septic peritonitis. Infectious pustular vulvovaginitis in cattle is a manifestation of bovine herpes virus. Causes white plaques on the vagina. Xylitol toxicity causes severe hypoglycemia. In a patient with pleural effusion, the best radiographic view to see the heart is ventrodorsal. The primary reservoir for Yersinia pestis (plague) is rats. The disease is spread by fleas. Chlamydophila felis commonly causes severe chemosis in the absence of other clinical signs. The most common cause of liver damage in broiler chickens is cholangiohepatitis from Closridium perfringens. This commonly causes ascites. When using a spay hook during an ovariohysterectomy, you are trying to retrieve the broad ligament of the uterus. Feline Immunodeficiency Virus is spread via bites. Mainly affects older, male, outdoor cats. Bile peritonitis is diagnosed with a fluid bilirubin concentration that is twice as high as serum bilirubin concentration. A common nail bed tumor is a melanoma. At this site, melanomas are frequently malignant.
o Melanoma cell with dark brown melanin granules. o Melanomas can be treated with the ONCEPT vaccine.
Horses with acute laminitis should be given Phenoxybenzamine, which is a vasodilator and increases blood flow to the digits. o Do not give corticosteroids. Alfalfa hay in California is high in magnesium and predisposes horses to enterolith formation. Mydriasis with a negative pupillary light response bilaterally in a head trauma patient indicates pressure / injury at the brainstem and indicates a bad prognosis. Hepatic lipidosis is common in anorexic obese cats. Most important therapy is esophagostomy tube placement and tube feedings. o In cows, hepatic lipidosis causes liver to float in formalin. Extrahepatic biliary obstruction can predispose patients to coagulopathies. This is because a decrease in bill will result in less absorption of vitamin K, which decreases coagulation factors, II, VII, IX, & X. Pulmonary arterial pressure done at elevations > 6,000 feet on animals over 12 months of age is a good predictor of genetic susceptibility to high mountain disease. o The lowest pulmonary artery pressure readings are the least susceptible animals. o High mountain disease causes pulmonary hypertension at high elevations, thus leading to right heart failure. This causes edema and dyspnea. The most common serovars associated with canine Leptospirosis are grippotyphosa, pomona, & bratislava. o Maintenance hosts for Leptospira are: Dogs – Canicola Rats – Icterohemorrhagiae Cattle – Hardjo Swine – Pomona Rodents - Grippotyphosa In adult horses, tetanus usually occurs from Clostridial spores entering a deep puncture wound. o In sheep, the most likely clinical sign seen with tetanus is trismus (sardonic grin). Bovine Viral Diarrhea is caused by a flavivirus. o Best method of prevention is testing heifer replacements with immunohistochemistry on a skin biopsy. Erythrocyte agglutination is highly suggestive of immune-mediated hemolytic anemia. o IMHA in cats is often due to Mycoplasma haemofelis infection. Diagnose with PCR. Treat with doxycycline or enrofloxacin. For cows with rumen acidosis, treat with magnesium oxide to raise rumen pH, IV fluids containing sodium bicarbonate, & systemic penicillin. Mycoplasma pneumonia in goats (caused by Mycoplasma mycoides subspecies mycoides) is spread via transmammary. o No therapy. Cull all culture positive animals and affected kids.
o In sheep, Mycoplasma pneumonia is caused by Mycoplasma ovipneumoniae and is spread via aerosol. Oleander contains a cardiac glycoside and is fatal to horses via arrhythmias and cardiac arrest. For dogs with pheochromocytomas (adrenal medulla tumor that produces catecholamines), tumor invasion into the vena cava is not necessarily associated with a worse prognosis. o Uncontrolled hypertension is associated with higher mortality. Pre-treat with phenoxybenzamine for several weeks before surgery to decrease hypertension. A lung lobe torstion (twisted lung lobe) will usually result in the bronchi of the middle lung lobe not visualized. In health, a bronchoalveolar lavage primarily consists of macrophages. o Horses with recurrent airway obstruction wil have neutrophilic inflammation on bronchoalveolar lavage. Will also have expiratory wheezes. When horses rear up and fall backwards, they commonly fracture the basisphenoid bone or basioccipital bone. o This causes lesions to cranial nerves VII & VIII. o Can cause rupture of the longus capitis and epistaxis. The plant Hypericum perforatum contains hypericin, which causes primary photosensitization. Feline squamous cell carcinomas commonly occur on the face in white cats exposed to sunlight. Vomiting is never seen with hyperadrenocorticism. The drug of choice to induce emesis in dogs is apomorphine; treat an adverse reaction with naloxone. o The drug of choice to induce emesis in cats is xylazine; treat an adverse reaction with yohimbine. Abomasal torstions will have hypochloremia, metabolic alkalosis, & hypokalemia. In horses, myositis can result in pigment nephropathy. Usually secondary to being overworked. With diabetic ketoacidosis, treat with Hulumin-R (regular insulin) because it is shortacting. o With normal feline diabetes, use Glargine or PZI insulin. Surgical repair of perineal hernias can cause fecal incontinence. They do not cause femoral nerve paralysis. Major clinical signs of diabetes mellitus are PU/PD, polyphagia, & weight loss. o Dogs normally have type 1 diabetes (insulin-dependent). o Cats normally have type 2 diabetes (insulin-resistant). Cats may be able to go in remission. o Major treatments are insulin, weigh loss, diet, and exercise.
Dogs can eat anything; cats should get a low-carbohydrate and highprotein diet. Obesity induces an insulin-resistant state. o Diagnostic indicators are hyperglycemia (> 200 dog, ~300 cat), glucosuria, ketonuria, increased liver enzymes and cholesterol o Fructosamine gives you a look at glucose control over the past 2 weeks. Very helpful for stressed cats that are hard to get accurate glucose readings. o For glucose curves, get first blood draw before eating and insulin. Get readings every 2 hours for 12 hours. o Can cause hypercholesterolemia. o An insulin dose that is too high can induce the Somogy effect, which causes a rebound hyperglycemia due to blood glucose falling too rapidly. o When controlling diabetes, want glucose to be 150 – 300. Most importantly, base on clinical signs. o When controlling diabetes, glucose will always be in the urine. Ketones will not. o Standard starting insulin is 0.25 – 0.5 units / kg per injection. o Regular insulin is short-acting and short-lasting. Useful in diabetic ketoacidosis. Lente is used in dogs. It is a porcine insulin and intermediate-lasting. Glargine is used in cats. It is a bovine insulin and long-lasting. o Dogs can get diabetic cataracts. Cats rarely get diabetic cataracts; they can get plantigrade stance. o Treat diabetic ketoacidosis with a constant rate infusion of Regular insulin. In the face of acidosis, potassium and phosphorous will decrease when you treat it. Supplement potassium when treating. Severe hypophosphatemia can cause hemolysis. The maximum amount of potassium you can give is 0.5 mEq/kg/ hour. Once patient is eating well and hydrated, switch to injectable insulin (Lente or Glargine). o DKA in cats can cause Heinz body anemia. o The shortest acting insulin is Regular; the longest acting is Ultralente. Tear production is controlled by the lacrimal nerve from cranial nerve VII (facial nerve). Don’t combine NSAIDs with steroids because it increases the risk for gastric ulceration, GI perforation, and renal failure. Immune-mediated hemolytic anemia will cause lethargy with fever and pale mucous membranes. Diagnose nasal aspergillosis with histopathology. The reversal agent for medetomidine is atipamezole. o Medetomidine & xylazine are alpha-2 agonists; reverse with yohimbine. o Opiates are reversed with naloxone. o Benzodiazepines (Midazolam & Diazepam) are reversed with flumanezil. o Phenobarbital does not have a reversal agent.
Appetite stimulants for small animals include mirtazapine, diazepam, oxazepam, & cyproheptadine. Vesicular exanthema of swine is caused by a calicivirus also affects sea lions. Neorickettsia risticii, which causes Potomac Horse Fever, requires paired titers to diagnose. o Treat with tetracyclines. Neorickettsia helminthoeca causes salmon-poisoning disease. o Dogs eat salmon, which have the flukes, which have Neorickettsia. o Causes vomiting, diarrhea, and thrombocytopenia. A left-sided ping on a cow indicates ruminal tympany or a left displaced abomasum. o A right-sided ping indicates gas in the spiral colon, gas in the cecum, or abomasal torsion. Abomasal torsion causes hypochloremia and metabolic alkalosis. o When hydrogen ions leave the cells, potassium rushes into the cells and causes hypokalemia. o Treat with IV saline with added potassium. Foxglove is a cardiotoxic plant. Aminocaproic acid promotes hemostasis by inhibiting plasminogen and stabilizing blood clots. Dogs with hepatic insufficiency or hepatic encephalopathy should be fed the maximum amount of protein they will tolerate without causing signs of encephalopathy. Portosystemic shunts cause high bile acids, microcytosis, ammonium biurate crystaluria, hypoproteinemia, hypoglycemia, and normal/increased liver enzymes. Carpal hygromas (fluid-filled swelling) in horses is treated with surgical exploration and drain placement. Moldy sweet potatoes with the fungus Fusarium solani have 4-ipomeanol. This is a pneumotoxic compound. Sertoli cell tumors can cause color changes in budgerigars. o Budgerigars commonly get iodine deficiency, which causes goiters (thyroid hyperplasia). Three major causes of protein-losing enteropathies are inflammatory bowel disease, lymphagniectasia, and lymphoma. Lymphocytic plasmacytic enteritis is consistent with inflammatory bowel disease. Treat with a hypoallergenic diet and prednisolone. Metronidazole can also be used to control bacterial overgrowth. o Lymphangiectasia is treated with a low-fat diet; steroids are not helpful unless it is secondary to another condition. Fat increases lymph production and causes further lacteal dilation. o A biopsy is helpful to differentiate IBD from lymphangiectasia because lymphangiectasia needs a low-fat diet and no steroids whereas IBD requires a hydrolyzed diet and possibly steroids.
o Cholangiohepatitis can be autoimmune or due to infection / neoplasia. Treat with prednisolone and ursodiol (which reduces hepatitis). Don’t need a special diet. Acute cholangiohepatitis typically has neutrophils in portal areas and carries a worse prognosis (50% long-term survival) than lymphocytic portal hepatitis (>90% long-term survival), which does not have neutrophils in portal areas. Only has plasma cell and lymphocyte infiltration. Feline triaditis consists of pancreatitis, inflammatory bowel disease, & cholangiohepatitis. Maropitant (Cerenia) is an anti-emetic for dogs and cats. Ionophoroes such as monensin commonly cause myocardial toxicity in horses. The safest antibiotic in guinea pigs is enrofloxacin. o Never use streptomycin in guinea pigs, it is fatally toxic. A patient with rapid shallow breathing and quiet lung sounds needs a thoracocentesis. In birds, the proventriculus is the glandular stomach. o The ventriculus is the grinding stomach. o The cloaca is the exit for the GI system. o The crop is an outpouching of the esophagus. Foot-and-Mouth disease causes oral and foot lesions in cattle, but horses are unaffected. o Foot-and-Mouth disease only affects cloven-hoofed animals. Hypothyroidism causes weight gain, poor coat, lethargy, heat seeking behavior, alopecia, pyoderma, myxedema. o Laboratory values include non-regenerative, normocytic, normochromic anemia. Also can include hypercholesterolemia. Hypothyroidism does not cause PU/PD. o A low total T4 is a screening test and is suggestive of hypothyroidism, but is not diagnostic (can have euthyroid sick syndrome). Diagnose with free T4 via equilibrium dialysis. o Treatment should raise free T4 to middle or high-middle reference range. Hyperthyroidism causes hyperactivity, poor hair coat, weight loss, increased BUN, & increased ALT. o Hyperthyroid animals should have low thyroid stimulating hormone (TSH). o To feel a thyroid slip, slowly palpate down the larynx all the way down to the thoracic inlet. Just feel a little slip. o Diagnose with increased serum total T4. If that is normal and you still suspect hyperthyroidism, diagnose with free T4 by equilibrium dialysis. o Hyperthyroidism can mask renal failure. o Treat with methimazole. Methimazole inhibits production of thyroid hormone, but the mass will keep growing. As such, animals likely will need a higher dose eventually.
A pure thyroid diet that is low in iodide (no other food) can be effective on its own. Not as many studies. Stop methimazole for 7 days before radioiodine-131 therapy so that the overactive cells can actually become overactive again and be targeted. Normal thyroid cells have a much lower metabolic rate because of negative feedback from high thyroid hormone and are thus not targeted by radioiodine-131. Hyperadrenocorticism can cause increased platelets and hypercholesterolemia. In horses, a rapidly spreading infection with fever and cough should make you suspicious for equine influenza (an orthomyxovirus). o Test for this and other viral diseases with viral isolation via nasopharyngeal swabs. Hemorrhage from guttural pouch mycosis is treated with surgical occlusion of affected internal or external carotid artery under general anesthesia. The most likely side effect for potassium bromide therapy is sedation. Infectious coryza is easily treated in birds because it is bacterial. o Avian influenza, infectious laryngotracheitis, & infectious bursal disease are caused by viruses and not easily treated. Gangrenous mastitis in sheep is caused by Staphylococcus aureus & Manheimia. Grave prognosis. Desmopressin acetate releases von Willebrand factor, which helps with clotting. o Can also give exogenous von Willebrand factor via fresh frozen plasma. Features of avian anatomy are 9 air sacs, a 4-chambered heart, complete tracheal rings, and heterophils as the major white blood cell. Agglutination on feline blood typing cards (which have antibodies against blood types) indicate the patient has that blood type. In cows, hypomagnesemia (grass tetany) causes death, staggering, tachycardia, pyrexia, nystagmus, and clamping of jaws. Occurs in lactating cows on lush pasture. Oral candidiasis in birds is caused by yeast and often occurs secondary to other illnesses or stresses. Causes oropharyngeal lesions. Treat with an anti-fungal such as fluconazole. The state veterinary board licenses veterinarians to prescribe drugs. Anesthetic gases are potent vasodilators. When a patient under anesthesia shows a drop in blood pressure, turn down the anesthetic gas first and give fluids before drugs. o Dobutamine can then be tried to raise blood pressure. Hemorrhagic gastroenteritis has hemorrhagic diarrhea with marked hemoconcentration. o Key findings are high PCV of 55 – 60% and normal total protein (that is not hemoconcentrated due to intestinal loss). Familial Shar Pei Fever (FSF) causes fever and tarsal swelling. Dogs with FSF are predisposed to amyloidosis, which can result in proteinuria. Chylous pleural effusion can be treated medically with a low fat diet and Rutin (stimulates protein breakdown and removal), although this normally fails.
o Surgical treatment is ligation of thoracic duct and pericardectomy. o Often is idiopathic. Castrating a puppy significantly decreases the risk of future benign prostatic neoplasia and prostatitis. o Castration does not reduce the risk of prostatic or bladder neoplasia. The most common cause of obstipation (severe constipation) in cats is megacolon. Malignant Catarrhal Fever is caused by a herpes virus carried by sheep. o Severe arteritis results in high fever, enlarged lymph nodes, and multisystemic signs. Can also cause corneal opacity and thick white nasal discharge. Border disease virus causes hairy shaker lambs. Treat infected corneal ulcers that have gram negative rods with topical tobramycin (an aminoglycoside). o Treat infected corneal ulcers that have gram positive rods with topical cefazolin. When rectally palpating the left side of a horse, you should feel the left kidney, pelvic flexure, small colon, & nephrosplenic space. o You should not feel the cecum on the left; if you do it is very distended. A melting corneal ulcer means there is an infection. o In horses, melting corneal ulcers are usually due to Pseudomonas. Mammary tumors in mice can be found on their dorsum. (Mammary tumors in mice can be found on any subcutaneous tissue.) o Mammary tumors in mice are very metastatic and have a poor prognosis.. The most important therapy for esophagitis is sucralfate. In dogs, the gallbladder is surrounded by the quadrate lobe and right medial lobe of the liver. Rhabdomyosarcomas are tumors of striated muscle. Bacterial pneumonia is treated with coupage, systemic antibiotics, oxygen, & nebulization. o Do not give cough suppressants, steroids, or diuretics.
With Addison’s you can see o Decreased albumin & cholesterol o Normocytic normochromic anemia o Can see low USG o Do an ACTH stimulation test if cortisol is less than 1 micrograms/dL. o Diagnose with ACTH stimulation o Abdominal ultrasound can reveal low small adrenal glands o Treat with DOCP (mineralocorticoid) injections every 28 days & Prednisone (glucocorticoid & mineralocorticoid) o Dexamethasone is the only steroid that doesn’t interfere with an ACTH stimulation test. o Commonly seen in poodles o Monitor with serum sodium and potassium Don’t treat Cushing’s based just on lab values; only treat if clinical signs are present.
Diagnose with ACTH stimulation or low dose dexamethasone suppression test. LDDST – get 3 blood readings pre, 4 hour post, 8 hour post 85% are pituitary dependent, 15% adrenal dependent LDDST suppresses PDH more than 50% of baseline at 4 hours and then increases at 8 hours. LDDST is not suppressed at 4 or 8 hours with ADH. LDDST suppresses a normal dog at 4 and 8 hours. Avoid stress with LDDST. A high urinary cortisol:creatinine ratio is suggestive of Cushing’s. Better at ruling out Cushing’s. Treat with Trilostane and Mitotane. Trilostane inhibits steroid formation. Mitotane destroys the adrenal gland. Too much mitotane can cause Addison’s disease. Monitor with an ACTH stimulation test.
Transitional cell carcinoma is treated with piroxicam (an NSAID) and carboplatin
chemotherapy. Lyme disease is caused by Borrelia burgorferi. o Causes erythema migrans in humans. o In dogs, causes anorexia, arthritis, lymphadenopathy, and fever. Red legs in frogs is a result of bacterial septicemia due to Aeromonus hydrophila.
Normal maintenance fluid requirements in dogs is 2.5 ml/kg/hour. o Anesthesia maintenance fluid requirements is 5 - 10 ml/kg/hour. This larger volume accounts for evaporation, metabolism, and lack of intake. Proliferative ileitis in hamsters is caused by Lawesonia intracellularis. Causes severe diarrhea and dehydration. o Treat with isotonic fluids + 2.5% dextrose + 0.45% NaCL, enrofloxacin, & Trimethoprim-sulfa (TMS). Murine respiratory mycoplasmosis in rats causes nasal discharge and ataxia. o Affects respiratory tract and middle ear. o Treat with oxytetracycline in water. Thelezia are Nematode worms that are found in ocular tissues. Transmitted by Diptera flies. Choanel atresis is one of the most common congenital defects in alpacas. This is a blocking of the opening between nasal and pharyngeal areas. o Causes problems breathing and nursing. o Euthanize. Specificity is the percentage of true negatives vs. false positives There is less than 7% incidence of medial meniscus injury after a tibial plateau leveling osteotomy Ascaris suum is a roundworm that migrates through the liver in pigs. This causes “milk spots.” Trichinella spiralis is a nematode that affects many species including pigs.
o In pigs, transmitted via ingestion of encysted larvae in muscle. o Humans get Trichinella spiralis by ingesting uncooked park. Remember, Listeriosis causes microabscesses. Septic peritoneal effusion has peritoneal fluid glucose at least 20 mg/dL less than blood glucose (bacteria use the glucose!). Hyperadrenocorticim has increased in ALP, ALT, & Cholesterol. No increase in BUN. Exocrine pancreatic insufficiency commonly causes small intestinal bacterial overgrowth due to lack of antibacterial factors in pancreatic fluid. Trichuris suis is the whipworm of pigs. o Affects older, weaned pigs. o Causes large bowel mucoid diarrhea. Most bladder stones in rabbits are calcium carbonate. Goats infected with caprine arthritis encephalomyelitis virus (CAEV) can develop a hardbag udder. o Cull the goat. o CAEV affects monocytes. The “big 5” neonatal calf diarrhea agents are E. coli, Rotavirus, Salmonella, Cryptosporidia, & Coronavirus. Hyperthyroidism can cause left ventricular hypertrophy. The site of colonic resection in a cat is limited by tension on the ileocolic artery. o The caudal mesenteric artery supplies the rectum and descending colon. o The left colic artery supplies the descending colon. o The pudendal artery supplies the external genitalia. o The ileocolic artery supplies the ascending and transverse colon. In horses, intermittent lameness and a bulge at the metacarpals are classic for tendonitis (bowed tendon). Leptospirosis in lambs is unique because it causes acute hemolytic anemia. o Best post-mortem diagnostic test is immunoperoxidase staining of renal tissue. Most common supraventricular arrhythmia in cattle is atrial fibrillation – can be caused by digestive disturbances. In horses, the most common cause of pneumonia is Streptococcus. o Rhodococcus equi is common in foals 2 – 6 months old. Tetanus antitoxin can cause anaphylaxis. o Tetanus works via a neurotoxin that blocks GABA release at the motor end plate, thus causing sustained muscle contraction. o Tetanus antitoxin prevents further toxin binding but will not reverse current clinical signs. FIP, a variant of feline coronavirus, is spread fecal-orally.
o Gasterophilus intestinalis is a bot fly larvae (stomach bot). Typically no clinical signs. Osteochondritis dissecans incidence is not reduced via cross-breeding. Cull affected pigs. Anaplasma marginale causes anaplasmosis. Causes extravascular hemolysis, so no hemoglobinuria. o Calves are resistant, so only affects adult cows. Thiopental is an ultra-short acting barbituate. Recovery depends on redistribution to tissues including fat. So, don’t give to Greyhounds because they have very little fat. For bovine surgery, only the cecum is only approached on the right side. The only veins that should enter the vena cava between the renal and hepatic veins are the phrenicoabdominal veins. o Any other veins that enter the vena cava in this position could be an extrahepatic portosystemic shunt. Activated charcoal does not bind alcohol, corrosives, some metals, and arsenic. Cryptosporidiosis in reptiles has no effective treatment; euthanize animals. o Causes regurgitation, weight loss, and debilitation. o Causes thickening of GI mucosa and loss of GI motility. In horses, anechoic regions in tendons on ultrasound indicate acute tendonitis (the anechoic regions are areas of hemorrhage and loss of tendon fibers). The most likely complication of clotrimazole is laryngeal inflammation. Bracken fern causes hemolytic anemia. Influenze viruses can readily undergo antigenic shift because of their segmented genome. Emphysematous cystitis, which is caused by gas-forming bacteria, is usually due to Cushing’s disease, diabetes mellitus, UTIs, or bladder stones. Dysfunction of the esophageal groove in calves can cause rumen acidosis, abdominal pain, and white putty feces. Cats require taurine and arachidonic acid in their diets. o Taurine deficiency in cats causes dilated cardiomyopathy and retinal degeneration. Basal cell tumors are the most common skin tumors in the cat. o Basal cell tumors are usually hairless, domed, and raised masses. o Usually found on the head, neck, and shoulders. o Usually benign. Sebaceous gland tumors are the most common skin tumors in dogs. o They are cauliflower-like and often ulcerate.
Round cell tumors include mast cell tumors, lymphoma, plasma cell tumors, histiocytomas, and transmissible venereal tumors. Vesicular stomatitis affects cattle and horses. o Causes fever and ulcerated tongues. In birds, Candidiasis is caused by the yeast Candida albicans. Usually affects young birds and is linked to hypovitaminosis A and spoiled feed. Fiddleneck, groundsel, ragwort, & senecios cause liver failure in horses because they have pyrrolizidine alkaloids. o Pyrrrolidizone alkaloids cause elevations in SDH, lactate, ALP, and a decrease in albumin. They also cause problems with hepatocyte division, thus leading to megalocytosis (large hepatocytes). Oak poisoning in horses causes GI signs. o Oak poisoning in cattle causes renal failure. The most cost-effective treatment for ruptured bladder in a feedlot steer is a perineal urethrostomy. o This is a salvage procedure to get the steer to market in a few months. Enrofloacin is good for treating UTIs associated with prostatitis. Yersinia enterocolitica & Trichinella spiralis affect humans who eat pork. They cause GI signs and appendicitis, although Yersinia causes the signs faster. Atrophic rhinitis in pigs is caused by Bordatella bronchiseptica & Pasteurella multocida. o No treatment, just cull. Ascaris suum are nematodes that infect the small intestine of pigs. o Cause white spots when migrating through the liver. Can also cause pulmonary edema when migrating through the lungs. o Trichuris suum is a whipworm that infects pigs’ cecums and large intestines. o Fasciola hepatica is a liver fluke of pigs. o Stephanurus dentatus is the kidney worm of pigs. Atricurium & succinylcholine are neuromuscular blockers. o Reversed by edrophonium and neostigmine (cholinesterase inhibitors). Guaifenesin is a centrally acting muscle relaxant. Ethmoid hematomas cause intermittent, recurrent, and unilateral epistaxis in horses. Influenza viruses are prone to antigenic shift because they have a segmented genome. Mare Reproductive Loss Syndrome (MRLS) is associated with eastern tent caterpillars. Anxiety-related problems can be treated with tricyclic anti-depressants such as clomipramine. o Side effects of clomaprine include vomiting, constipation, anorexia, and sedation. Theriogenology
Pig gestation is 3 months, 3 weeks, and 3 days (114 days). Stages of the estrous cycle are: o Proestrus - follicles of ovary start to grow.
o Estrus - female is sexually receptive. o Metestrus - Corpus luteum formation. o Diestrus - Dominated by corpus luteum. o Anestrus - No estrus cycle. A “heat” consists of proestrus and estrus. Vaginal epithelium thickens and cornifies in response to estrogen in estrus. Llamas and alpacas are induced ovulators. The preferred site for practical artificial insemination of mares and cows is intrauterine. Ideal suture pattern for a cow uterus after C-section is Utrecht pattern. The most common postpartum pathogen leading to endometritis in cattle is Arcanobacterium pyogenes. o Treat endometritis with intrauterine penicillin or tetracycline. On ovary, ovulation ovulation depression corpus hemorrhagicum corpus luteum corpus albicans Maternal recognition of pregnancy is via: o embryo signaling with bovine interfeuron-tau in cow o transuterine migration in mare o lifespan of corpus luteum equaling pregnancy length in dog and cat In cows, the 4 cardinal signs of pregnancy are fetus, amniotic vesicle, chorioallantoic membrane, and placentomes. The fetus initiates stage 1 of parturition, which is initiation of myometrial contractions. o Stage 2 of parturition is expulsion of fetus. o Stage 3 of parturition is delivery of placenta. Epitheliochorial placentas have 6 total layers, 3 maternal layers, and are found in horses, swine, and ruminants. o Endotheliochorial placentas have 4 total layers, 1 maternal layer, and are found in dogs and cats. o Hemochorial placentas have 3 total layers, no maternal layer, and are found in rodents and primates. A uterine biopsy can predict if a mare can carry a foal to term. o Do uterine biopsies for endometritis, pyometra, & early embryonic death. o Don’t do uterine biopsies in pregnant mares; this can cause abortion. The best way to diagnose a uterine infection in a mare is uterine cytology. Pregnancy can be confirmed via ultrasound in cattle at 28 days. Cats, ferrets, rabbits, and camelids are induced ovulators. The hormone responsible for milk letdown is oxytocin. The hormone that rises and is responsible for pseudopregnancy when progesterone falls is prolactin. Signs of uterine torsion in a late-term mare are colic, frequent urination, and palpating the broad ligament coursing over the uterus. Pneumovagina heavily predisposes mares to vaginitis and endometritis. The most common cause of dystocia in the bitch is uterine intertia.
A bitch in estrus will have vaginal cytology with >90% cornified epithelial cells (look like flakes with no nucleus). Neonatal rabbits (kits) must nurse 1 - 2 times per day. In a cow, you will see parturition 48 hours after administering dexamethasone. o Dexamethasone + PGF-2alpha will lyse a corpus luteum if cow is 5 – 8 months pregnant. Progesterone levels are highest in diestrus, when the corpus luteum is active. In pigs, an ascending reproductive tract infection can be caused by E. coli, Streptococci, Staphylococcus, Pseudomonas, & Actinomyces. Lysing a mature corpus lutem in a cow will return her to estrus in 3 days. Risk factors for metritis in cattle are retained fetal membranes, dystocia, stillbirth, & twinning. To synchronize a dairy cow, 2 injections of PGF-2 alpha should be given 11 – 14 days apart. o Giving PGF2-alpha during anestrus has no effect. The Whitten (buck) effect induces sheep and goats to ovulate at the same time. The Whitten (buck) effect is done via introduction of a new male. Mammary gland hyperplasia occurs in youg, intact female cats. Is non-painful. Treat with ovariohysterectomy. Most common testicular tumor in the horse is a seminoma. Colonic torsions commonly occur in mares that are a few weeks post-partum. Prolactin is stimulated by suckling and promotes milk production. In dogs, radiographs can see puppy skeletons at 45 days post-ovulation. In horses, placentas are considered retained after 3 hours post-parturition. Treat with oxytocin and uterus lavage. In pigs, E. coli, Streptococci, Staphylococci, & Actinomyces can cause reproductive failure via ascending infection of the reproductive tract. The most effective way of synchronizing lactating pigs is batch weaning at 3-4 weeks. This results in estrus about 5 days later. Gestation length of goats and sheep is 150 days. Progesterone is essential for maintenance of pregnancy in all domestic mammals. o The pig depends on ovarian progesterone throughout pregnancy. o In cows, the latter half of pregnancy is maintained by ovarian and placental progesterone. o In horses, the ovarian source of progesterone peaks relatively early in gestation and is gradually replaced by placental progesterone. o In sheep, the placenta takes over progesterone production early in gestation. Fescue causes reproductive failure in mares. Cow lactation lasts 305 days, then the cows are dried off for 60 days (the last 2 months of pregnancy). o Cows reach peak lactation 4 – 8 weeks post-parturition.
The placentome is the relationship between the uterine endometrium and placenta. o In cows, the placentome consists of the maternal caruncle (mom drives the car) & fetal cotyledon. In the bitch, dark red vaginal discharge can be seen up to 6 weeks postpartum. o Sub-involution of placental sites can cause fresh bleeding for up to 15 weeks. o Bitches do not normally get retained placentas. Repair of a pneumovagina in horses involves placing horizontal sutures at the dorsal aspect of the labia and increasing the mare’s weight. o Pneumovaginas are normally seen in older, thin mares. Goats and sheep reach puberty at 6 months old. o Cows reach puberty at 14 months old. Goats have a 21 day estrous cycle Theriogenology Species Comparison
Gestation Length 63 days
Type of Heat Cycle Average interestrous interval of 7 months
Estrous Cycle Length (Averages) 9 days Proestrus 9 days Estrus 2 - 3 months Diestrus 4 - 5 months Anestrus
Seasonally polyestrous, spring through fall
1 day Proestrus 7 days Estrus 7 - 21 day Interestrous cycle during mating season
Polyestrous all year
21 day Estrous cycle. Estrus lasts 8 - 18 hours in the cow. Cows ovulate 24 – 30 hours after the onset of estrus.
Important Notes Oocytes undergo meiosis before fertilization occurs. Estrus has falling estrogen and rising progesterone. Induced ovulators (copulation stimulates LH surge, which stimulates ovulation). In the absence of pregnancy, oxytocin receptors form in uterus during diestrus, which leads to production of PGF-2alpha.
The cow is unusual because she ovulates after estrus. Chorioallantoic membrane slip can be felt at 30 days pregnancy. Fetus can be felt at 60 days pregnancy. Placentomes can be palpated at 75 90 days pregnant.
Seasonally polyestrous, spring and summer
21 day Estrous cycle Estrus is 6 days long
Fremitus can be felt at 4 months on the ipsilateral horn & 7 months bilaterally. Prostaglandin-F will lyse a corpus luteum between 5 - 17 days of the estrous cycle. Can palpate pregnancy at 20 days. Horses have endometrial cups which produce progesterone between 45 - 120 days of pregnancy.