VetPrep-NonSA

Question 1

You have arrived at a farm with a history of acute outbreak of sudden death. Pigs average 80 lbs and the producer has lost 25 pigs out of 1,150 in the last 2 days. Several of the dead pigs have blood tinged fluid coming out of their noses. Which of the following is your top differential?

a. vit D deficiency
b. Actinobacilus pleuropneumoniae
c. mycoplasma hyopneumoniae
d. porcine reproductive and respiratory syndrome (PPRS)
e. rodenticide poisoning

Answer 1

B. The correct answer is Actinobacillus pleuropneumoniae (APP). The virulence of APP is due to exotoxin production by the bacteria which causes a vasculitis and hemolysis, especially in the lungs.

Rodenticide poisoning of an entire group of pigs is extremely rare as it would require large amounts of poison mixed in the feed. Mycoplasma hyopneumoniae is a slow growing organism and is not associated with an acute outbreak with sudden death. Porcine reproductive and respiratory syndrome is a common cause of respiratory outbreaks in pigs but usually does not cause high mortality by itself (co-infections are the culprit). Vitamin D deficiency alters calcium and phosphorus homeostasis.

Question 2

A 4-day old bull calf has been unable to bear weight on the right forelimb since birth which was an assisted delivery in anterior presentation using a calving aid. There is loss of muscle tone and markedly reduced reflexes in the right foreleg (see image). The right foreleg is non-painful on palpation. The left foreleg and the hindlimbs are weight bearing with normal reflexes. What should you tell the farmer?
[pic - carpus bent, dorsal surface on ground]

a. The calf appears to have a radius fracture from traction at birth and is likely to improve with splinting of the distal limb
b. The calf appears to have right sided radial nerve paralysis due to traction at birth and prognosis for recovery is grave; the calf should be euthanized
c. The calf appears to have a fracture of the distal third metacarpal growth plate due to traction at birth and has an excellent prognosis to improve with supportive care
d. The calf appears to have a right brachial plexus avulsion due to traction at birth and it is unknown whether it will improve with time

Answer 2

The most likely conditions to consider for this calf are brachial plexus avulsion and radial nerve paralysis due to traction at birth. This injury results in an inability to extend the elbow, carpus and fetlock and bear weight on the affected limb with loss of muscle over the shoulder with resultant prominent spine of the shoulder blade. There is a dropped elbow, scuffing of the hooves as the leg is moved forward, and the foot is knuckled over at rest. Depending on the severity of injury, many calves can recover with supportive care. It is often recommended to carefully splint the distal limb to prevent contraction of the flexor tendons.

Other differentials could include spinal cord trauma or congenital sarcocystosis. Fractures are less likely given the presentation and lack of pain on palpation.

Question 3

You are called to a farm that just purchased 500 head of feeder pigs averaging 55 lb. The pigs arrived 3 days ago and everything seemed fine until today. Today there are 6 pigs that are lying down on their sides and paddling and a few others that are weak and staggering. What should you do next?

a. check feed for mycotoxin
b. check for rodents
c. feed availability
d. water availability
e. check abx in ration

Answer 3

d. The correct answer is to check water availability in all pens. The clinical presentation is very typical for water deprivation/salt toxicity. Water deprivation will result in acute cerebral edema due to the accumulation of sodium ions in the brain. To prevent further water damage, water must be turned back on slowly (small amounts frequently) to prevent further cerebral edema from occurring as the animals become re-hydrated.

Question 4

You are hired by the potential buyer to examine a valuable 3-month old calf for purchase as part of a pre-purchase examination. You note that the calf appears healthy other than having a temperature of 103F, 39.4 C and having some small raised lesions in the mouth around the gums of the incisors and on the dental pad, as shown in the photo. You suggest some lab tests and another exam in three weeks, and tell the buyer that you think the calf most likely has ________.

Answer 4

bovine papular stomatitis
BPS is one of two parapox viruses that affect cattle; the other is pseudocowpox. The third parapoxvirus is contagious ecthyma of sheep and goats. Humans can get all three. BPS is a common and usually mild “calfhood” disease, often unnoticed, but it has caused significant mortality in some groups of calves (perhaps due to some immunosuppression). The best course of action is to isolate this calf and rule out BVD by testing for it, then wait to see if the calf recovers in about three weeks. The raised lesions, and lack of other oral lesions, and lack of GI signs tend to make BPS more likely here than BVD.

Question 5

You examine a herd of sheep and find that many sheep have proliferative, crusting lesions of the mucocutaneous junctions of the mouth and nose. They are otherwise relatively healthy, although some of the nursing females have similar lesions on their udders. The farmer reports that many of his sheep have had these before and that it eventually just goes away. What is the most likely diagnosis?

a. Foot-and-mouth disease
b. Vesicular stomatitis
c. Bluetongue
d. Contagious ecthyma

Answer 5

d. The correct answer is contagious ecthyma. FMD, VSV, and bluetongue cause vesicles and ulcers rather than proliferative, crusting lesions and usually will have other systemic signs as well; also, they are unlikely to recover spontaneously. Contagious ecthyma is a zoonotic poxvirus.

Question 6

A group of 4-week old piglets presents for depression, anorexia, and lethargy. They all have brown exudative spots on the skin of their heads, axillae, and groins. Some of the lesions are brown to black crusts. What is the most likely diagnosis?

a. Pityriasis rosea
b. Staphylococcus hyicus
c. Pediculosis
d. Dermatosis vegetans

Answer 6

b. The correct answer is Staphylococcus hyicus. S. hyicus infections in pigs are also known as exudative epidermitis or greasy pig disease. The disease affects piglets less than 8 weeks of age and seldomly adults. The clinical signs and lesions are those described in the question. Morbidity and mortality is usually high in younger pigs. There are not many other swine diseases that appear clinically like this, so diagnosis is usually based on history and clinical signs.

Pediculosis causes pruritus and anemia. Dermatosis vegetans is a semilethal hereditary defect that causes macules and papillomas around the coronary band of pigs. Pityriasis rosea is characterized by raised circular lesions on the ventral abdomen. Pityriasis rosea resolves on its own in a few weeks without any treatment.

Question 7

Greasy pig disease

Answer 7

staph hyicus
high morbidity and mortality in young pigs.
CS: brown exudative spots, some have brown/black crusts

Question 8

Caseous Lymphadenitis

Answer 8

caused by corynebacteriumpsuedotuberculosis

Question 9

Bovine diseases caused by clostridia

Answer 9

black leg
black disease
redwater (bacillary hemoglobinuria)
malignant edema

Question 10

Aujeszky’s disease

Answer 10

eradicated from US
pseudorabies in pigs
CS: few day old pigments trembling, hypersalivation, ataxia, nystagmus, seizures, death.

Question 11

A concerned client calls your clinic for information regarding a pet macaque she reluctantly inherited from her next door neighbor. She understands that non human primates should not be kept as pets and will be donating the animal to a primate sanctuary. She received the following health information from the neighbor and wants to make sure it is accurate since she will be forwarding it to the sanctuary with the macaque. Which of the these statements on the zoonotic diseases of macaques is NOT true?

a. Herpes B is viral disease of macaques but it is not transmissible to humans.
b. Macaques and other nonhuman primates can be vaccinated safely with killed rabies vaccines.
c. Macaques and other non human primates are susceptible to measles and, therefore, should be vaccinated.
d. Macaques and other non human primates are susceptible to tuberculosis.

Answer 11

a. Herpes B, caused by herpesvirus simiae, is transmissible to humans and can cause fatal infections through bites, scratches, or exposure to the tissues or secretions of macaques. Therefore, this is the only statement that is NOT true and therefore the correct answer for this question.
Killed rabies vaccines are safe and recommended in non human primates in contact with humans. Macaques and other non human primates are susceptible to tuberculosis cause by Mycobacterium tuberculosis, M. bovis, and M. avium. Measles can cause infection and disease in non human primates therefore measles, mumps and rubella (MMR) vaccines are recommended.

Question 12

Several weaner pigs have developed anorexia, followed by diarrhea and edema of the eyelids, forehead and lips. The pigs also have dyspnea and are open mouth breathing. Some are weak and circling. What pathogen is the most likely cause?

a. Porcine Parvovirus
b. Transmissible gastroenteritis virus
c. Salmonella typhimurium
d. Clostridium tetani
e. Enterotoxogenic E. coli

Answer 12

The edema disease producing E. coli produce a heat stable toxin called Stx2e (Shiga toxin 2e). When absorbed into the blood, this toxin destroys endothelial cells in small vessels, resulting in blood clots, hemorrhage, ischemic necrosis, and edema in vital organs, including the brain.

Question 13

Before administering a general anesthetic to a ruminant it is vital to do what?

a. Place a fistula in the rumen so that rumen gas can escape to prevent bloat
b. Feed only grain for 24 hours prior to surgery to allow the rumen to empty out
c. Withhold feed and water for a period sufficient to minimize the chance that bloat or regurgitation will occur
d. Use a large dose of atropine
e. Pass a large stomach tube and leave it in place

Answer 13

c. In cattle this usually require 36 hours or more without feed and 12 to 24 hours without water. In small ruminants it requires less time. You should also keep the head slightly lower than the body so that if any regurgitation does occur the feed material runs out of the mouth quickly.

Question 14

Which of these treatments is least effective for treating cyanide toxicity?

Supplemental oxygen
Methylene blue
Sodium thiosulfate
Sodium nitrate

Answer 14

a. The answer is supplemental oxygen. Cyanide blocks cellular respiration and blocks oxidative transport. As a result, hemoglobin cannot release oxygen to the tissues and venous blood stays saturated with oxygen and is bright red. Supplemental oxygen is unlikely to change this. The other three options are the usual treatments for cyanide toxicity.

Question 15

You examine a small flock of chickens and find that about 5% of the 1-2 week old birds are exhibiting neurologic signs of ataxia, imbalance, and head and wing tremors. Postmortem examination of one of the affected animals reveals neuronal axon-type degeneration (ghost cells) in the brain stem and anterior horn of the spinal cord. You suspect that this is a case of avian encephalomyelitis. Which one of these treatment/management strategies is most appropriate for this disease?

a. Vaccinate 10-15 week old breeding animals
b. Vaccinate chicks at 1-3 days old
c. Treat chicks with oxytetracycline
d. Identify heterozygotes and do not breed them
e. Administer serum from recovered animals to affected animals

Answer 15

a. Avian encephalomyelitis is caused by a picornavirus. Transmission is commonly vertical (transovarian) but also can be lateral (fecal-oral) as the virus can survive in feces for several weeks. Many older animals remain carriers. Therefore, treating only the symptomatic animals is not an effective strategy. This is not a genetic disease and cannot be bred out of the population.

The best prevention strategy is to vaccinate breeder animals to prevent vertical transmission to progeny and to provide them with maternal immunity during the susceptible period.

Question 16

A pet rabbit presents to you for mild dermatitis. On physical exam, you note a scaly dermatosis with areas of thinning on the dorsum. What is the most likely etiology?

 Cuterebra
 Notoedres
 Cheyletiella 
 Demodex 
 Sarcoptes

Answer 16

c. The correct answer is Cheyletiella. This is the fur mite of rabbits and typically causes clinical signs as described in this question.

Question 17

You are examining a 5-year old pony for lethargy, anorexia, and mild intermittent colic. Upon physical examination, you notice the abnormal finding in the image. Consumption of which of the following can produce these clinical signs and physical examination findings?

a. Red maple leaves (Acer rubrum)
b. Oak leaves and acorns (Quercus sp)
c. Yellow star thistle (Centaurea solstitialis)
d. Black walnut (Juglans nigra)

Answer 17

a. The sclera appears icteric. In combination with the clinical signs, ingestion of Red maple leaves would result in these signs due to hemolysis and low oxygen content of the blood. Oak is toxic but causes diarrhea and abdominal pain, whereas Black walnut is associated with laminitis. Yellow star thistle causes nigropallidal encephalomalacia resulting in CNS signs.

Question 18

You are asked to examine some feeder pigs that have stopped eating yesterday. The group is lying down and seems lethargic. They have fevers of 105-106F (40.6 -41.1 C), firm dry feces, and the skin has rhomboid-shaped red blotches scattered on it. What treatment should be recommended?

 Chloramphenicol
 Metronidazole
 Streptomycin
 Penicillin 
 Gentamicin

Answer 18

Erysipelas is susceptible to penicillins, as well as tetracyclines (usually), lincomycin and tylosin. Chloramphenicol and nitroimidazoles (including metronidazole) are not approved for food animal use.

Question 19

A dairyman’s favorite cow was bred by a new bull a few weeks ago and now his cow has pyometra. What agent is most likely responsible for causing the cow’s pyometra?

Brucellosis
Campylobacter fetus
Leptospirosis
Tritrichomonas foetus

Answer 19

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

Question 20

Which of the following is not a cause of teat lesions?

 Herpes mammillitis 
 Pseudocowpox
 Anaplasmosis
 Bluetongue virus
 Vesicular stomatitis

Answer 20

The correct answer is Anaplasmosis, which is a cause of extravascular hemolysis. Pseudocowpox is a parapox virus and results in proliferative teat lesions. Vesicular stomatitis is a reportable disease caused by a rhabdovirus. It is reportable because it is similar in presentation to foot and mouth disease. Clinical signs include ulceration of the teats and mouth. Bluetongue and herpes mammillitis also result in ulcerative lesions.

Question 21

You are asked to perform a post mortem examination on a 2-year old sheep recently moved to a feedlot after giving birth to twins in the early summer. The farmer noted no signs of illness prior to finding the sheep acutely dead in the morning. An image of the gross post-mortem finding is shown below. You note widespread necrosis of the small intestine with fetid smelling contents. No volvulus is seen. You evaluate the urine and find glucosuria. There is softening of the brain and kidney tissues. Which of the following management considerations should you look into?

a. Evaluate pasture for toxic plants and the medication history of the flock
b. Evaluate vector control program and shearing protocols
c. Evaluate the density of the herd and other causes of stress
d. Evaluate breeding soundness evaluation program and quarantine program for newly introduced sheep
e. Evaluate herd vaccination program and diet

Answer 21

You should be suspicious of type D Clostridial enterotoxemia based on the acute mortality and necropsy lesions in the intestines. Additional findings consistent with enterotoxemia are the glucosuria and soft kidneys. Enterotoxemia is sometimes referred to as overeating disease because of its association with changes in diet to concentrates or higher grain concentrations. It is also sometimes referred to as pulpy kidney disease because of the changes that occur to the kidneys.

Enterotoxemia caused by Clostridium perfringens type D affects sheep and goats of all ages (from 1 week to several years of age).

A diagnosis of enterotoxemia is suggested when the sudden death of concentrate-fed animals that have not been vaccinated for Clostridium perfringens type D occurs.

In young animals, this commonly occurs after abundant nursing or grazing on improved pastures, high quality hays and/or concentrates/grains. In older animals as in this case, the disease corresponds with the finishing or feedlot period and is often associated with a high grain diet. Enterotoxemia is one of the most common causes of death in feeding lambs.

Prevention depends on vaccination against Clostridial toxoid and avoiding rapid changes in diet.

Question 22

Several 6 month-old calves have died on a large ranch, and you have performed a post-mortem exam and diagnosed blackleg (see image). The owner, who has never vaccinated his calves, would like your recommendations for prevention.

a. Give Fusobacterium necrophorum vaccine to to all calves starting at 4 to 6 months of age
b. Vaccinate all calves at 4 to 6 months of age with killed vaccine containing Clostridium septicum and several other common Clostridial organisms. Correct Answer
c. Vaccinate all animals starting at one year of age and annually thereafter, using killed vaccine containing several common Clostridial organisms
d. Give penicillin whenever handling the calves, as this eliminates the Clostridium chauvoei spores from tissues
e. Give Clostridial antiserum to all calves at the time they are handled for branding and castration

Answer 22

b. 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 23

Which of the following viruses has a latent phase within the trigeminal ganglion of chickens, allowing a clinically healthy chicken to carry this virus into a new poultry flock?

 Infectious bronchitis virus
 Infectious bursal disease virus
 Lymphoid leukosis virus 
 Fowl pox virus
 Infectious laryngotracheitis virus

Answer 23

ILT is a herpesvirus with a latent phase in neural tissue.

Question 24

A 5-year old ewe presents as a result of isolating herself. She had just twinned two months ago and she is not vaccinated. On physical examination, she has an enlarged left half of the udder. It is cold, blue, and black. Serosanguinous milk can easily be expressed, and it is foul-smelling (see image). What two organisms can cause this presentation?

a. Staphylococcus aureus and Mannheimia hemolytica
b. Arcanobacterium pyogenes and Streptococcus agalactiae
c. Pseudomonas aeruginosa and Pasteurella multocida
d. E. coli and Mycoplasma agalactiae

Answer 24

Gangrenous mastitis is caused by Mannheimia spp. and Staphylococcus aureus and occurs sporadically during the first 3 months of lactation. It is generally associated with poor milk supply related to ewe undernutrition and over vigorous suckling by the lambs.

Despite antibiotic and supportive therapy, the prognosis is grave, and gangrenous udder tissue eventually sloughs leaving a large granulating surface with superficial bacterial infection. The granulation tissue continues to proliferate over the coming months. These ewes are unsuitable for breeding stock. The infected granulation tissue and resultant drainage lymph node enlargement would result in carcass condemnation (and raise genuine welfare concerns). The fleece is very poor because growth has occurred during this period of illness. The ewe should be euthanized for welfare reasons at first presentation.

Control measures include ensuring ewes are well fed. Concentrates should be supplied to ewes and lambs when pasture is poor. No ewe should be expected to rear triplets. Teat lesions should be identified and treated with topical antibiotics.

Question 25

A client brings the one-half inch grub shown in the image to you one spring day, telling you it emerged from a hole in the back of one of his prize show cattle. He wants to know what to treat his cattle with and when. a. Organophosphates in summer b. Moxidectin now, in spring c. Thiabendazole in early fall d. Ivermectin in February e. Ivermectin in early fall

Answer 25

This is a cattle warble called Hypoderma. The 2 species are H. bovis and H. lineatum. They undergo a long migration in tissues and only emerge from the back of the animal in spring. The crucial treatment time is early fall when larvae are just beginning to migrate in tissues. Organophosphates or one of the macrocyclic lactones (ivermectin, doramectin, eprinomectin or moxidectin) are effective.

Question 26

What is the main vector of Heartwater disease? Boophilus Dermacentor Amblyomma Rhipicephalus

Answer 26

The correct answer is Amblyomma spp. Heartwater is a disease found in Africa and the West Indies, caused by Ehrlichia ruminantium. The disease is tick borne and results in fatal encephalitis in sheep, goats and cattle.

Question 27

A herd of beef cows has been presented to you with an increase in lameness, diarrhea, poor body condition and infertility. You note achromotrichosis among several of the cows and decide to measure copper levels. What is the most sensitive way to measure copper levels? a. Serum sample copper levels b. Plasma sample for copper levels c. Splenic biopsy copper levels d. Brain sample for copper levels e. Liver biopsy for copper levels

Answer 27

A liver biopsy is needed. Copper is stored in the liver, and the liver is very good at maintaining copper homeostasis until the very end. Therefore, the blood levels might look good, but in reality, the liver may have very little copper left to share with the rest of the body.

Question 28

Which of the following mycotoxins can cause hyperestrogenism and pseudopregnancy in pigs? ``` Aflatoxin Ochratoxin Fumonisin Zearalenone Ergot ```

Answer 28

Zearalenone is a potent estrogenic metabolite produced by some Fusarium species. Young gilts will be most affected. Young boars will also have reduced libido.

Question 29

A 16-year old budgerigar presents with progressive unilateral paresis of the right leg (see image). There is normal flexion and extension of the hip joint with decreased flexion, extension, and sensation below the knee. The remainder of your skeletal and neurologic examination is unremarkable. Which of the following is most likely in this bird? ``` Botulism Renal neoplasia Lead toxicosis Marek's disease Intervertebral disc disease ```

Answer 29

The signalment and progressive unilateral paresis are most suspicious for renal neoplasia of budgerigars. Affected birds develop paresis due to pressure exerted on the sciatic nerve by a renal tumor. There is typically normal flexion and extension of the hip joint with decreased flexion, extension, and sensation below the knee as described here. Disc disease is uncommon in birds. Lead toxicity can lead to peripheral neuropathy and paresis but typically there are more multifocal or other accompanying signs such as polyuria/polydipsia, gastrointestinal signs, wing droop, head tilt, or convulsions. Marek's disease typically affects younger animals. Botulism typically presents with flaccid paralysis of the legs, wings, and neck.

Question 30

The carrier and reservoir of the herpes virus responsible for causing malignant catarrhal fever (MCF) in cattle in North America is chiefly the ____________? ``` Sand flies Culicoides sonorensis (a midge) Cattle persistently infected as a fetus Wildebeest Sheep ```

Answer 30

A high percentage of normal appearing sheep in North America are infected with MCF virus. Wildebeests are the reservoir of the African form of MCF.

Question 31

Which of the following is not a form of anthrax in humans? Ocular Cutaneous Intestinal Pulmonary

Answer 31

The correct answer is ocular. Sorry, it's a human health question, but it is a potential biochemical warfare agent and the public expects veterinarians like you to know this.

Question 32

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? ``` IM parathyroid hormone Oral propylene glycol IV calcium gluconate SQ bovine somatotropin IM tetracycline ```

Answer 32

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 33

A 1-year old unvaccinated Angus steer presents as a result of acute lameness and depression. He has historically been healthy and one of the best animals in the group. On physical exam, there are no signs of trauma and the steer is febrile. A crepitant, edematous swelling is seen on the muscles of the left shoulder. It is hot and painful to the touch. Assuming there are no signs of trauma, what is the most likely diagnosis? ``` Clostridium chauvoei (blackleg) Mycoplasma bovis Corynebacterium pseudotuberculosis Clostridium hemolyticum Clostridium difficile ```

Answer 33

The correct answer is Clostridium chauvoei (blackleg). Clostridium chauvoei results in infection after gaining access to the blood stream via the alimentary tract and then depositing in muscle. This is a serious disease, and animals will die if left untreated. Cattle should be vaccinated at 3 to 4 months of age against this and other Clostridial diseases. Clostridium hemolyticum causes liver lesions, and the toxin results in acute hemolysis and often in death. Clostridium difficile usually results in gastrointestinal disease in horses. Corynebacterium pseudotuberculosis results in large external bleeding sores on the skin of cattle and boils and internal abscesses in sheep and goats. Mycoplasma bovis can cause sepsis, joint infections and mastitis.

Question 34

What is the causative agent of turkey coryza? Pasteurella multocida Haemophilus paragallinarum Bordetella avium Ornithobacterium rhinotracheali

Answer 34

The correct answer is Bordetella avium. Turkey coryza or avian bordetellosis is an acute respiratory disease of turkeys with high morbidity and low mortality. Clinical signs include nasal discharge, foamy eyes, and cough. Diagnosis is via isolation on MacConkey agar or serology. A vaccine is available but has mixed results. Antimicrobial therapy is usually unrewarding.

Question 35

A mouse presents for patchy alopecia on the head. You suspect a dermatophyte infection in the mouse. What is the most common dermatophyte responsible for ringworm in mice and rats? ``` Microsporum canis Microsporum gypseum Trichophyton mentagrophytes Microsporum nanum Trichophyton verrucosum ```

Answer 35

The correct answer is Trichophyton mentagrophytes. Microsporum gypseum can occasionally cause dermatophytosis in mice but less frequently than T. mentagrophytes. Approximately 98% of the cases of ringworm in cats are caused by M. canis. In dogs, most cases (approximately 70%) are caused by M. canis followed by M. gypseum and T. mentagrophytes. M. nanum typically affects pigs. T. verrucosum typically affects cattle and horses. T. mentagrophytes is characterized by patchy alopecia, crusting, and flaking on the head. Diagnosis is based on identification of the organism on infected hairs. Treatment is not usually necessary, since the disease is self-limiting, but griseofulvin is efficacious as an antifungal.

Question 36

At what point is the placenta of a cow considered retained? 2 hours post-partum 12 hours post-partum 24 hours post-partum 6 hours post-partum

Answer 36

The correct answer is after 12 hours. Usually, the fetal membranes are passed in 2 to 8 hours; after 12 hours, it is considered retained. They appear to occur more commonly in dairy than beef cattle. The rates are reported to be in the range of 8 to 12 % of all single births in dairy cows.

Question 37

Illness in young calves caused by Eimeria sp. is best treated with which of the following? ``` Amprolium Penicillin Levamisole Ivermectin Tetracycline ```

Answer 37

A number of drugs can be used to treat or prevent coccidiosis. The treatment dosage is generally higher but for fewer days than the preventive dosage. Monensin- and sulfa-containing drugs are also frequently used as treatments.

Question 38

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? a. Acute bovine pulmonary edema and emphysema b. Free gas bloat secondary to chronic bronchopneumonia c. Frothy bloat d. Type 2 vagal indigestion e. Bovine respiratory syncytial virus pneumonia

Answer 38

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.

Question 39

tx for nonspecific calf diarrhea?

Answer 39

most often associated with enteropathogenic E coli, rotavirus, or cryptosporidium. The calf develops hypovolemia and metabolic acidosis and requires sodium-containing IV fluids which contain additional alkali such as sodium bicarbonate. One can assess that the calf is severely acidotic given that it is lethargic and unable to stand. While oral fluids may also be useful, at this stage, the calf will require IV fluids.

Question 40

Which of the following is the most important problem associated with leptospirosis in pigs? Abiotrophy of the spleen Purple extremities due to vasculitis Reproductive failure Chronic kidney disease

Answer 40

The correct answer is reproductive failure. Acute leptospirosis in young pigs causes fever, anorexia, hemolytic anemia, hemoglobinuria, jaundice, and failure to grow. Chronic infections in dams cause reproductive failure as late term abortions, mummies, or weak piglets that die in a few days. Dams usually recover, conceive again, and carry their litters to full term.

Question 41

You are asked to examine a group of pigs that have just arrived from a sow farm. The pigs are 24 days old and approximately 2% of the pigs have crusty lesions over their body especially in the face area. Some pigs have lesions covering their entire body. What should be your recommendation for plan of action? Separate affected pigs and treat with injectable antibiotics Correct Answer Immediately call federal authorities Treat all pigs with a topical insecticide effective against lice Nothing, pigs will grow out of the condition Euthanize all affected pigs

Answer 41

The crusty lesions all over the body, especially on the face in pigs of this age are highly suggestive of "greasy pig" disease caused by Staphylococcus hyicus. The bacterial pyoderma is contagious so it is helpful to segregate affected pigs. As pigs grow, their immune system does a better job in controlling the infection, but with a history of having some pigs with lesions all over the body, antibiotic treatment is necessary to prevent the condition from worsening in these young pigs which can lead to dehydration and/or systemic spread. There is no need to call federal authorities, since no vesicular lesions are noted.

Question 42

You have arrived at a farm with a history of acute outbreak of sudden death. Pigs average 80 lbs and the producer has lost 25 pigs out of 1,150 in the last 2 days. Several of the dead pigs have blood tinged fluid coming out of their noses. Which of the following is your top differential? ``` Actinobacillus pleuropneumoniae Rodenticide poisoning Mycoplasma hyopneumoniae Porcine reproductive and respiratory syndrome (PPRS) Vitamin D deficiency ```

Answer 42

The correct answer is Actinobacillus pleuropneumoniae (APP). The virulence of APP is due to exotoxin production by the bacteria which causes a vasculitis and hemolysis, especially in the lungs. Rodenticide poisoning of an entire group of pigs is extremely rare as it would require large amounts of poison mixed in the feed. Mycoplasma hyopneumoniae is a slow growing organism and is not associated with an acute outbreak with sudden death. Porcine reproductive and respiratory syndrome is a common cause of respiratory outbreaks in pigs but usually does not cause high mortality by itself (co-infections are the culprit). Vitamin D deficiency alters calcium and phosphorus homeostasis.

Question 43

``` tx for roundworms (ascarids) in pigs? Fluconazole Flumazenil Metronidazole Fenbendazole Sulfamethazine ```

Answer 43

d. fenbendazole Treatment options are wide and include ivermectin, fenbendazole, pyrantel, levamisole and other ascaracides. Fenbendazole is a benzimidazole anthelmintic with a broad spectrum against many gastrointestinal parasites such as roundworms, hookworms, whipworms, pinworms, and strongyles.

Question 44

Psuedorabies in pigs

Answer 44

Older pigs with the disease show respiratory clinical signs such as sneezing, nasal discharge, and coughing. Pseudorabies in young nursing piglets tends to cause neurologic signs such as incoordination, tremors, blindness, paddling, coma, and death. Weaned pigs may have both neurologic signs and respiratory signs such as sneezing, nasal discharge, and coughing. Older pigs tend to only have respiratory signs. Pregnant sows affected with the virus often have reproductive failure.

Question 45

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? ``` IV saline, large volumes IV calcium Blood transfusion IV magnesium Broad spectrum antibiotics ```

Answer 45

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 46

A dairy has experienced an increase in abortions from midterm to term, as well as the birth of weak calves with neurologic signs. Based upon histopathologic lesions and herd serology, you have diagnosed Neospora caninum. Which of the following steps to help control the disease is most correct? Keep dogs and coyotes away from cows and cow feed Keep cats away from cows and cow feed Depopulate and bring in clean seronegative cows Keep raccoons away from cows and cow feed Treat all cows in the herd with long acting tetracycline

Answer 46

The canine is the definitive host and sheds oocysts in the feces, which cause the disease when consumed by cattle. Like cattle, deer may also be infected as intermediate hosts. The dogs are initially infected by eating infected tissues from the cattle, most commonly an aborted fetus.

Question 47

You examine a herd of sheep and find that many sheep have proliferative, crusting lesions of the mucocutaneous junctions of the mouth and nose. They are otherwise relatively healthy, although some of the nursing females have similar lesions on their udders. The farmer reports that many of his sheep have had these before and that it eventually just goes away. What is the most likely diagnosis? Vesicular stomatitis Foot-and-mouth disease Bluetongue Contagious ecthyma

Answer 47

The correct answer is contagious ecthyma. FMD, VSV, and bluetongue cause vesicles and ulcers rather than proliferative, crusting lesions and usually will have other systemic signs as well; also, they are unlikely to recover spontaneously. Contagious ecthyma is a zoonotic poxvirus.

Question 48

Nine out of 100 adult cattle are found weak, depressed, and staring into space. On physical exam, they are found to be pale, icteric, and febrile. None of them have hemoglobinuria. The nine cattle all arrived at the ranch approximately one month ago. What is your most likely diagnosis? Bacillary hemoglobinuria Anthrax Anaplasmosis Leptospirosis

Answer 48

The correct answer is Anaplasmosis. The causative agent is Anaplasma marginale. The clinical signs are fairly straight forward, and you need to pick up on a couple key features. The fact that new adults are sick is one feature because cattle are resistant to clinical Anaplasmosis as calves. Also, it should be remembered that hemoglobinuria with Anaplasmosis is never seen because it is all extravascular hemolysis. Since there is no hemoglobinuria, leptospirosis, bacillary hemoglobinuria, and anthrax can be ruled out. Additionally, icterus with anthrax is not seen.

Question 49

A cow presents with a hard bony mass lesion at the ventral mandible (see image). Which treatment is known as being effective but is not recommended in pregnant animals as a result of concerns about it causing abortion and not for use in lactating dairy animals as a result of food safety issues? ``` Intravenous sodium iodide Penicillins Corticosteroids Oxytetracycline Ceftiofur ```

Answer 49

The correct answer is intravenous iodine. It is commercially available as a 20% solution at a dose of 15 ml/100 lbs (66mg/Kg). The clinical signs are suggestive of lumpy jaw, which is caused by Actinomyces bovis. The prognosis is poor, so most animals should be culled. Penicillins are reportedly successful at arresting the lesion in very early cases. However, there may be a better chance with intravenous 20% sodium iodide. That being said, due to concerns that iodide may cause abortion and because of food safety concerns, the label warns not to use sodium iodide in pregnant or lactating cattle. Ceftiofur may not be used in this extra label fashion.

Question 50

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

Answer 50

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

Question 51

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? ``` Weight loss No symptoms Hematochezia Dehydration Seizures Inappropriate mating behavior ```

Answer 51

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 52

A cow presents to you as a result of decreased milk production. On physical exam you determine the cow has a much stronger pulse on expiration than she does on inspiration. What is this pulse associated with? Pericardial effusion Atrial fibrillation Atrial premature contractions Patent ductus arteriosus

Answer 52

The correct answer is pericardial effusion. Pulsus paradoxus is an exaggeration of normal variations in the pulse during respiration, in which the pulse becomes weaker as one inhales and stronger as one exhales. It is characteristic of constrictive pericarditis or pericardial effusion. Atrial premature contractions are more likely to result in pulse deficits. Atrial fibrillation is likely to result in pulsus alternans, in which you see two quick normal pulses in a row followed by no pulse. A patent ductus arteriosus usually is found only in very young animals and results in waterhammer pulses which is a large bounding pulse with a sharp peak and very rapid decline.

Question 53

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? a. Treat with penicillin b. Treat with rifampin c. Cull all cattle that test positive d. Treat with chloramphenicol e. Treat with tetracycline

Answer 53

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 54

What is the usual route of transmission of Mycoplasma pneumonia in sheep? Transmammary Transplacental Aerosol Fecal-oral

Answer 54

The correct answer is aerosol. Mycoplasma pneumonia, also referred to as enzootic pneumonia or atypical pneumonia, is caused primarily by Mycoplasma ovipneumoniae in sheep. It is usually spread from older animals to younger animals by the respiratory route (aerosol). Note that this route is in direct contrast to transmission in goats which have a different species of Mycoplasma (M mycoides ssp mycoides) that is primarily spread in milk.

Question 55

spider lamb syndrome

Answer 55

Another name is Ovine Hereditary Chondrodysplasia. It is caused by a semilethal autosomal recessive gene. Lupine may result in arthrogryposis if consumed during gestation. Chlamydia will usually cause abortions. Skunk cabbage (Veratrum californicum) causes craniofacial deformities if consumed by ewes on the 14th day of gestation. If the plant is consumed at approximately 30 days of gestation, you will see limb and bone shortening in the metacarpal and metatarsal joints.

Question 56

A 2-year old Holstein bovine female calved 14 days ago with a difficult dystocia. Her ears are erect and she seems to over-react to external stimuli. In response to your clapping, her third eyelids partially cover her eyes, and then eventually retract. The signs in this patient are all compatible with which of the following? a. A uterine infection with Clostridium difficile b. A systemic infection with Clostridium difficile c. A systemic infection with Clostridium septicum d. A uterine infection with Clostridium tetani e. A uterine infection with Arcanobacter pyogenes f. A uterine infection with Clostridium botulinum

Answer 56

The clinical signs and history are all very characteristic for a cow with tetanus. The causative agent is Clostridium tetani. C. botulinum is responsible for a flaccid paralysis and rapid death, not the hyper-alert signs shown here. C. difficile is notorious for bowel infections, especially in horses. Systemic infection with C. septicum will result in massive necrosis of damaged tissues, but would not show the hyper-excitability seen in the cow in question. A uterine infection with Arcanobacter pyogenes would result in endometritis or at worst, pyometra, but would not cause any overt signs as seen in this question.

Question 57

A 4 year old dairy cow presents for circling to the right, poor appetite and depressed attitude. On physical exam, the right side of the cow's face and the right ear are drooping (facial paralysis). What is the most likely causative agent for these signs? Histophilus somni Listeria monocytogenes Pasteurella multocida Mycoplasma bovis

Answer 57

Listeria monocytogenes is the most common CNS infection in adult ruminants. Infection is often associated with feeding of silage. It causes microabscesses in the brain resulting most commonly in unilateral cranial nerve signs such as facial nerve paralysis, vestibular signs (circling), head tilt, and dysphagia. CN V-XII may be involved. Head pressing may be seen in some cases. It is also a cause of abortions. Treatment is with tetracyclines or high levels of penicillin. Mycoplasma bovis in young calves can affect some animals with otitis interna, so the calf shows ( uni or bilateral) facial paralysis, ear droop, and vestibular signs such as head tilt , nystagmus, and ataxia. There may be purulent discharge from the aural canal. M bovis can also cause pneumonia, polyarthritis and tenosynovitis. This condition can be difficult to treat and result in many animals with chronic illness. Histophilus somni can commonly be a cause of respiratory disease and septicemia, as well as TEME (thromboembolic meningoencephalitis) or otitis media /interna in young feedlot animals where they exhibit head tilt, nystagmus, circling and stumbling. They may also develop ipsilateral facial paralysis. So in this case the main differential is the age of the animal and the fact that this is often a feedlot animal, plus H somni tends to be a more fulminant systemic disorder.

Question 58

how to test herd for BLV?

Answer 58

ELISA to detect antibodies has been found to have the best sensitivity and specificity of all tests on a herd basis. If the individual with multiple enlarged lymph nodes is also ELISA positive, a necropsy should be performed. PCR can be negative in infected individuals with low numbers of circulating infected lymphocytes, even when they are ELISA antibody-positive. Few infected cows that are still asymptomatic have elevated blood lymphocyte counts. Performing biopsies on 200 cows is not practical when there are other better tests.

Question 59

7m old steer died after severe fever, dyspnea, cough, resp distress. necropsy - fibrinopurulent bronchopneumonia. which bacterium?

Answer 59

Mannheimia hemolytica

Question 60

Which of the following is a common cause of meningitis in goat kids? Streptococcus suis Mycoplasma mycoides Cryptococcus neoformans Actinomyces bovis

Answer 60

The correct answer is Mycoplasma mycoides. Streptococcus suis is known to affect foals, and Actinomyces and Cryptococcus neoformans are seen in adult horses.

Question 61

Which cells does caprine arthritis encephalitis virus infect? ``` Lymphocytes Neutrophils Basophils Monocytes Eosinophils ```

Answer 61

monocytes

Question 62

A macaw presents to your clinic with prolapsed cloacal tissue that is erythematous and proliferative. What is this lesion likely to be? ``` Cloacal papilloma Cloacal leiomyoma Cloacal adenoma Cloacal fibrosarcoma Cloacal adenocarcinoma ```

Answer 62

The correct answer is cloacal papilloma. This is the most common gastrointestinal tumor of birds and is seen most commonly in Amazons and macaws. A viral etiology is suspected but not proven. Treatment is surgical removal or chemical cautery.

Question 63

Many young (<9 months) rams in a herd develop swelling and edema around the head and neck. You diagnose bighead (Clostridium novyi Type A). What is the treatment? a. No treatment is necessary, the disease is self-limiting b. Wound debridement and penicillin c. Vaccinate the affected animals against Cl novyi d. Cull or isolate affected animals

Answer 63

b. The correct answer is debridement and penicillin. Culling is unnecessary as Clostridium novyi is found in the soil and feces of healthy animals. Bighead is caused when it enters through wounds obtained during head butting activities. The disease can be fatal if untreated. The key to reducing the incidence of this disease is management to reduce head wounds and vaccination with multivalent clostridial toxoids.

Question 64

treatment for woody tongue

Answer 64

Na idodide IV (once and then 10 days later)

Question 65

average estrus duration?

Answer 65

8-18 h (can be up to 50h)

Question 66

You encounter some infertile rams in a commercial flock of sheep. You wish to determine why they might have palpable hard lumps on the epididymis and whether this could be the cause of infertility before culling is considered. Which of the following would be the best way (sensitive, specific, and cost-effective) to determine this? a. Perform biopsy of testicular tissue b. ELISA for Brucella ovis c. Culture semen samples from these rams d. ELISA for Corynebacterium pseudotuberculosis e. History of Corynebacterium pseudotuberculosis lesions in the flock

Answer 66

b. If these rams have not been given the B. ovis vaccine, then a positive B. ovis ELISA means that B. ovis is likely the cause of the epididymitis and infertility.

Question 67

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

Answer 67

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

Question 68

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

Answer 68

This is the typical presentation for epizootic bovine abortion (EBA), also known as foothill abortion. The agent causing foothill abortion remains a subject of some investigation but a 2005 molecular study identified a novel deltaproteobacterium as being present in the Ornithodoros coriaceus tick vector and in DNA from fetal thymuses. With EBA, cows usually do not experience abortions again in later pregnancies and exposure to endemic areas before breeding age can also prevent abortions. Other control options may include control of the tick vector or prophylactic antibiotic use. You can lower your index of suspicion for bovine herpesvirus (Infectious bovine rhinotracheitis virus) because there is no respiratory disease seen in this case; abortions from herpesvirus occur throughout pregnancy and fetuses are typically autolyzed with foci of necrosis in the liver or no gross lesions. Ponderosa pine needle abortions occur in the last trimester but cows are often moribund after delivery and hemorrhage. There are usually no specific fetal lesions.

Question 69

calf diptheria

Answer 69

fusobacterium necrophorum

Question 70

Which protozoan is not considered to infect cattle? Sarcocystis cruzi Sarcocystis hirsuta Sarcocystis hominis Sarcocystis tenella

Answer 70

tenella does sheep and goats

Question 71

Which of the following disorders of goats can be controlled by genetic testing? Penile papillomas Scrapie Corynebacterium pseudotuberculosis Beta mannosidosis

Answer 71

Beta mannosidosis is a disorder of Anglo-Nubian goats that causes fatal neurological symptoms in newborns and is an autosomal recessive mode of inheritance. Scrapie is a prion-caused disorder. In sheep, scrapie can be controlled by genetic testing to eliminate the susceptible animals. To date that is not possible with goats. Corynebacterium pseudotuberculosis is a bacterial disease known as boils. Papillomas are viral.

Question 72

A cow is suspected of having copper deficiency. In order to make an accurate diagnosis, a liver biopsy is necessary. In what rib space and on which side should the liver biopsy be performed? a. Right side half way between the last rib and the pelvis b. Right side between ribs 10-11 c. Right side between ribs 7-8 d. Left side between ribs 8-9

Answer 72

b. The correct answer is right side between ribs 10-11. You may also be able to go in between ribs 11-12 on the right side. This can be done percutaneously and standing using local anesthesia. Make a line between the hip and the elbow and go in along that line in the indicated rib space. A suitable biopsy instrument is the Truecut or similar instrument.

Question 73

You have arrived at a farm with an acute outbreak. The farmer has lost 25 pigs in the last two days. The pigs are all from the same building and are from a group of 950 four-week old pigs. The pigs arrived on the farm approximately 8 days ago. Upon arrival to the farm, you perform a necropsy on 8 out of the 20 dead pigs available. Seven of the first eight pigs you necropsy have lesions similar to those seen on the attached photo. You then perform a quick walk through of the building and do not identify any other sick pigs. What should you do next? (pic- norm? white gunk/fatcovered viscera?) a. Select five non-treated, acute live pigs from the rest of the group to euthanize and collect samples for a diagnostic workup b. Have the owner inject all remaining pigs in the building with ceftiofur c. Continue performing a necropsy on the remaining 12 dead pigs d. Have the feed company add 400g per ton of chlortetracycline to the next batch of feed

Answer 73

The correct answer is to have the owner inject all remaining pigs in the building with ceftiofur. The photograph depicts a classical presentation for polyserositis. The top two differentials for polyserositis in four week old pigs would be Streptococcus suis and Haemophilus parasuis. Because of the high mortality in only two days, Haemophilus parasuis would be your top differential and suggests a true emergency situation. As seen in the case history, many times the rest of the pigs appear to be normal. The only way to try and stop the outbreak is to inject all pigs ASAP. Although adding 400g per ton of chlortetracycline may be effective in preventing an outbreak, it is not the correct choice at the time of an outbreak. Feed delivery may be a week away, and even if feed could be delivered that same day, it would take three or four days before the pigs would get enough antibiotic via the feed. Immediate action is critical. There is no need to necropsy additional pigs, as a pattern has already been established. It is practically impossible to find an acute live pig in cases of Haemophilus parasuis outbreaks; pigs are usually just found dead.

Question 74

What minimum proportion (%) of a herd or population must be immunized (not just vaccinated) in order for an infectious disease spread to begin to slow and eventually stop, if the basic reproductive rate (R0) for the disease is 3? (Note: it is given that R0 must be <1 for disease spread to decline and, at that point the immune proportion will be 1-1/R0). 67% 33% 100% 90%

Answer 74

Ro (R naught) measures the number of new cases of an infectious disease generated by a contagious individual entering a naive (completely susceptible) population. For example, estimates for smallpox Ro = 5, and Ebola Ro = 2 to 4. In this example, one infected individual will transmit the agent, resulting in infection, to three other individuals. Propagation depends on the coefficient of transmission for the particular infectious agent and on the contact rate among individuals. The disease will spread/propagate through the population as long as at least one new case is generated by each infected case. The disease will cease to spread when the R0 drops below 1, indicating that a sufficient proportion of the population has developed immunity and no longer can support transmission of the agent to others. In developing vaccination strategies, a fundamental question is what proportion of the population must be immunized (vaccination that results in immunity) in order to prevent a new case from spreading infection through the population. The higher the R0, the higher the proportion of the population that will have to be immunized. When R0 < 1, the proportion of the population that is immune will be 1-1/ R0. This formula is derived from differential equation calculations of a geometric propagation of infection and subsequent increase in proportion of the population that becomes immune and no longer capable of supporting and transmitting the agent. The purpose of this question was to highlight this basic rate, which has been referred to frequently in the press, as related to Ebola and measles, and is the basis for veterinary vaccination programs against diseases like rinderpest and foot-and-mouth disease. Giesecke J. Modern Infectious Disease Epidemiology, pgs. 120, 238.

Question 75

What is the cause of Porcine Stress Syndrome (PSS), a condition which can result in poor meat quality where the meat is pale, soft and sour? It can also result in increased body temperature, dyspnea, or death during transport stress. ``` Selenium deficiency Porcine coxsackie virus Genetic mutation Hypernatremia Hypomagnesemia ```

Answer 75

The ryr-1 (Ryanodine receptor) gene is the locus responsible, and homozygous animals will have PSS. The industry has made a concerted effort to test pigs and eliminate the gene, and the prevalence is now low in most countries.

Question 76

Which of the following is the most effective way of synchronizing lactating pigs? Batch wean at 3-4 weeks Introduce a new male 2 shots of PGF2-alpha 11-14 days apart Use an MGA (megestrol acetate) implant

Answer 76

The correct answer is to batch wean the pigs in 3-4 weeks. This results in estrus 4-6 days later. As long as a pig is lactating she will not ovulate so you need to stop lactation by weaning the piglets. PGF2-alpha is ineffective because the pig only has a small window in which the corpus luteum is mature and responsive to the PGF2-alpha. MGA implants are not really used in pigs. The Whitten effect (exposure to male pheromones) will not work if they are lactating.

Question 77

A number of young growing pigs on a commercial hog farm are experiencing head tilt, incoordination, reduced weight gains, and weak rear limbs. Most have normal vital signs, and you suspect a nutritional deficiency. Which of the following deficiencies might cause such clinical signs? ``` Thiamine (vitamin B1) Vitamin A Folic acid Sodium Vitamin D ```

Answer 77

A shortage of vitamin A in the diet can lead to these signs in young pigs, especially an increase in middle ear infections, as also seen in turtles. In sows it can cause embryonic mortality and congenital defects in their offspring.

Question 78

normal SCC in milk

Answer 78

<200k

Question 79

Pick the ideal suture pattern for a uterus after a Caesarian section in a cow. Horizontal mattress Near-far-far-near Utrecht pattern Simple interrupted

Answer 79

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

Question 80

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

Answer 80

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