NAVLE Small Ruminant Medicine (Sheep and Goats)

Question 1

A 3-year-old dairy goat presents with progressive weight loss, decreased milk production, and bilateral carpal swelling.
Lung auscultation reveals diffuse crackles.
Cerebrospinal fluid analysis shows mononuclear pleocytosis.
The most likely diagnosis is:

Accepted Answer

Caprine Arthritis Encephalitis (CAE) virus infection

Answer

Caseous lymphadenitis (Corynebacterium pseudotuberculosis)

Answer

Mycoplasma mycoides subsp. capri polyarthritis

Answer

Maedi-Visna virus infection

Question 2

A flock of sheep presents with sudden deaths in 2-to-6-week-old lambs that were thriving until 24 hours prior. Necropsy reveals hemorrhagic abomasal and intestinal lesions with gas in the intestinal lumen. Gram-positive rods are cultured. The most appropriate preventive strategy for next year's lamb crop is:

Accepted Answer

Vaccinate ewes with Clostridium perfringens types C and D toxoid 4–6 weeks before lambing

Answer

Administer prophylactic penicillin G to all lambs at birth

Answer

Feed sodium bicarbonate free-choice to buffer rumen pH

Answer

Vaccinate lambs at birth with Clostridium novyi type B bacterin

Question 3

A 2-year-old sheep presents with acute blindness, head pressing, and opisthotonus. The animal has been on a high-grain diet with limited forage. Blood thiamine levels are low. Which treatment should be administered immediately?

Accepted Answer

Thiamine (vitamin B1) 10–20 mg/kg IV or IM

Answer

Intravenous dextrose 50% at 0.5 mL/kg

Answer

Dexamethasone 0.1 mg/kg IV to reduce cerebral edema

Answer

Magnesium sulfate IV to treat suspected hypomagnesemia

Question 4

Ovine Progressive Pneumonia (OPP) caused by Maedi-Visna virus is best controlled in a flock through which strategy?

Accepted Answer

Test-and-cull seropositive animals combined with separating lambs from seropositive ewes at birth

Answer

Annual vaccination with killed-virus OPP vaccine

Answer

Prophylactic long-term tetracycline administration in feed

Answer

Parenteral ivermectin to eliminate the arthropod vector

Question 5

A goat herd experiences multiple does with profuse watery diarrhea, weight loss, and bottle jaw (submandibular edema) over several months. Fecal egg counts reveal heavy Haemonchus contortus burdens. Which anthelmintic resistance testing method is most appropriate to guide drug selection?

Accepted Answer

Fecal Egg Count Reduction Test (FECRT) comparing pre- and post-treatment counts

Answer

Baermann technique to detect larvae in feces

Answer

McMaster flotation to identify the species causing disease

Answer

Larval development assay using pooled fecal cultures

Question 6

Scrapie is a prion disease of sheep. Which characteristic most accurately describes the diagnostic approach in suspect live animals?

Accepted Answer

Immunohistochemistry of lymphoid tissue (rectal biopsy or third eyelid) for PrPSc accumulation

Answer

Serum ELISA for PrPSc antibodies

Answer

PCR of blood for scrapie prion RNA

Answer

Cerebrospinal fluid analysis showing 14-3-3 protein elevation