ICVA - International Council for Veterinary Assessment Small Ruminant Herd Health Questions and Answers

Question 1

A goat producer reports several animals in their herd have developed large, thick-walled abscesses around the jaw and shoulder regions. When one ruptures, it discharges a thick, non-odorous, greenish-yellow pus. Which of the following is the most likely causative agent?

Accepted Answer

Corynebacterium pseudotuberculosis

Answer

The clinical signs described, specifically the formation of thick-walled, non-odorous abscesses containing caseous (cheese-like) pus in the lymph nodes of goats, are characteristic of Caseous Lymphadenitis (CL). The causative agent of CL is Corynebacterium pseudotuberculosis. While other bacteria like Trueperella pyogenes and Staphylococcus aureus can cause abscesses, the classic presentation in multiple animals within a herd strongly points to CL.

Question 2

A sheep flock is experiencing an outbreak of sudden death in the fastest-growing lambs that are approximately 2 months old. The lambs are on a high-concentrate diet. Necropsy of a recently deceased lamb reveals pulpy kidneys. Which preventative measure is most crucial for the remaining lambs and future prevention?

Accepted Answer

Vaccination with a Clostridium perfringens type D toxoid.

Answer

The scenario describes classic signs of enterotoxemia type D, also known as 'overeating disease' or 'pulpy kidney disease'. This disease is caused by the overgrowth of Clostridium perfringens type D in the intestine, often triggered by a sudden increase in concentrate consumption. The bacteria produce epsilon toxin, which causes the characteristic signs and lesions. Vaccination with a C. perfringens type D toxoid (often in a combination CD&T vaccine) is the most effective preventative measure.

Question 3

Which of the following is the most effective and practical method for monitoring the level of anemia in individual sheep and goats to make selective deworming decisions against Haemonchus contortus?

Accepted Answer

FAMACHA© system scoring of mucous membrane color.

Answer

The FAMACHA© system is a validated, practical tool used to estimate the level of anemia in small ruminants by assessing the color of their lower eyelid mucous membranes. This is directly correlated with the blood-sucking activity of Haemonchus contortus, the barber pole worm. It allows for targeted selective treatment of only anemic animals, which helps to slow the development of anthelmintic resistance. While fecal egg counts are useful for monitoring overall pasture contamination and dewormer efficacy, they are less practical for on-the-spot individual treatment decisions.

Question 4

A 4-month-old wether (castrated male goat) presents with straining to urinate, tail flagging, and vocalization. You observe crystals around the preputial opening. Which of the following dietary management strategies is most critical for preventing this condition in a herd of male small ruminants?

Accepted Answer

Maintaining a calcium to phosphorus ratio of at least 2:1.

Answer

The clinical signs are classic for obstructive urolithiasis, a common and life-threatening condition in male small ruminants. The most common uroliths are phosphatic (struvite) stones, which form in alkaline urine when there is an excess of phosphorus relative to calcium in the diet. Feeding a diet with a calcium-to-phosphorus ratio of at least 2:1 is the cornerstone of prevention. This ratio helps bind excess phosphorus in the gut, preventing its absorption and excretion in the urine. High-grain diets are often low in this ratio, predisposing animals to the condition.

Question 5

A producer brings in a 6-month-old lamb exhibiting neurological signs including blindness, star-gazing (opisthotonos), and ataxia. The lamb was recently moved to a high-grain finishing diet. What is the most likely diagnosis and immediate treatment?

Accepted Answer

Polioencephalomalacia (PEM); parenteral thiamine (Vitamin B1).

Answer

The combination of neurological signs (blindness, star-gazing) and a recent history of a dietary change to high concentrates strongly suggests Polioencephalomalacia (PEM), or cerebrocortical necrosis. PEM is most commonly caused by a thiamine (Vitamin B1) deficiency, which can be induced by the proliferation of thiaminase-producing bacteria in the rumen under conditions of high carbohydrate intake. Immediate intravenous or intramuscular administration of high doses of thiamine is the treatment of choice and is often diagnostic, with rapid improvement seen in early cases.

(ICVA) International Council for Veterinary Assessment Practice Test

(ICVA) International Council for Veterinary Assessment Practice Test

ICVA - International Council for Veterinary Assessment Small Ruminant Herd Health Questions and Answers