ICVA - International Council for Veterinary Assessment Small Ruminant Herd Health Questions and Answers 1 — 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?
- Trueperella pyogenes
- Staphylococcus aureus
- Corynebacterium pseudotuberculosis (Correct answer)
- Pasteurella multocida
Correct answer: Corynebacterium pseudotuberculosis
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?
- Administration of a broad-spectrum antibiotic to all lambs.
- Immediate deworming of the entire flock for Haemonchus contortus.
- Vaccination with a Clostridium perfringens type D toxoid. (Correct answer)
- Supplementing the diet with high levels of thiamine.
Correct answer: Vaccination with a Clostridium perfringens type D toxoid.
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?
- Routine fecal egg counts for every animal in the herd.
- Body condition scoring.
- Daily observation for signs of lethargy and weakness.
- FAMACHA© system scoring of mucous membrane color. (Correct answer)
Correct answer: FAMACHA© system scoring of mucous membrane color.
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?
- Increasing the protein content of the diet to promote growth.
- Maintaining a calcium to phosphorus ratio of at least 2:1. (Correct answer)
- Supplementing with high levels of magnesium.
- Providing a diet primarily composed of alfalfa hay.
Correct answer: Maintaining a calcium to phosphorus ratio of at least 2:1.
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?
- Listeriosis; high doses of penicillin.
- Scrapie; no treatment, reportable disease.
- Tetanus; tetanus antitoxin and wound debridement.
- Polioencephalomalacia (PEM); parenteral thiamine (Vitamin B1). (Correct answer)
Correct answer: Polioencephalomalacia (PEM); parenteral thiamine (Vitamin B1).
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.
Question 6: To comply with the National Scrapie Eradication Program in the United States, which of the following is a primary requirement for the official identification of most sheep and goats involved in interstate commerce?
- A farm-specific ear notch pattern registered with the state.
- A color-coded neck chain for each animal.
- An official USDA-approved ear tag with a flock identification number. (Correct answer)
- A detailed description of the animal's markings in a logbook.
Correct answer: An official USDA-approved ear tag with a flock identification number.
The USDA's National Scrapie Eradication Program requires official identification for most sheep and goats in interstate commerce to enable effective trace-back in the event of a disease outbreak. The primary method of official identification is a USDA-approved ear tag that displays an official flock identification number (or premises ID) and a unique individual animal number. While other forms like registry tattoos may be acceptable under specific conditions, the standard requirement is the official ear tag.
ICVA - International Council for Veterinary Assessment Small Ruminant Herd Health Questions and Answers 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?