Top 15 Small Ruminant Diseases for NAVLE: Essential Insights

Top 15 Small Ruminant Diseases: A Comprehensive NAVLE Guide (Part 2)

Introduction

This guide continues to explore critical diseases affecting small ruminants, providing essential diagnostic and treatment insights for veterinary professionals preparing for the NAVLE. Understanding these conditions is crucial for effective management in sheep and goats.

6. Caprine Arthritis Encephalitis (CAE)

Classic Case:
CAE affects adult goats with symptoms like progressive arthritis, swollen joints (especially carpus), weight loss, and indurative mastitis. In kids aged 2-4 months, it causes encephalomyelitis, presenting as weakness, ataxia, and potential paralysis.

Diagnosis:

• Etiology: RNA lentivirus, similar to ovine progressive pneumonia virus.
• Diagnostic Tools: Serology (AGID, ELISA), biopsy, or necropsy.

Treatment:

• Management: No cure; provide supportive care, such as deep bedding and good feed.
• Prevention: Isolate kids at birth, feed heat-treated colostrum, and conduct biannual herd serology.

Pearls:
CAE is widespread in dairy goats, with a 65% prevalence in U.S. herds. Most infections occur via colostrum or milk, with signs developing later.

7. Pregnancy Toxemia

Classic Case:
Common in late-gestation dams, especially with multiple fetuses and those that are over- or under-conditioned. Symptoms include anorexia, depression, bruxism, tremors, and recumbency.

• note fat vacuoles within hepatocytes

Diagnosis:

• Tools: Measure serum beta-hydroxybutyric acid (BHB), urine ketones, and check for hypoglycemia or hypocalcemia.

Treatment:

• Mild Cases: Oral propylene glycol and calcium.
• Severe Cases: IV therapy, C-section if needed, and euthanasia if necessary.

Prevention:
Maintain appropriate body condition scores, provide adequate nutrition, and use ionophores to improve feed efficiency.

Pearls:
Pregnancy toxemia is due to inadequate nutrition and increased energy needs in late gestation, leading to hepatic lipidosis and ketosis.

8. Urolithiasis

Classic Case:
Presents as partial or complete urethral obstruction, causing urine dribbling, hematuria, colic, and potential bladder rupture with abdominal swelling.

Diagnosis:

• Tools: Clinical signs, ultrasound, radiography, and abdominocentesis for ruptured bladders.

Treatment:

• Obstruction Management: Tube cystotomy, antispasmodics, or urethral process amputation.
• Rupture Management: Drain uroperitoneum, correct electrolyte imbalances, and perform urethrostomy as needed.

Prevention:
Adjust diet to prevent stone formation and ensure proper calciumratios.

Pearls:
Urolithiasis is common in males due to their urethral anatomy. Stone type is diet-dependent, with high-grain diets increasing risk.

9. Copper Toxicity in Sheep

Classic Case:
Chronic copper toxicity is more common, leading to acute hemolytic crisis with depression, jaundice, and renal failure.

Diagnosis:

• Tools: Measure blood and liver copper concentrations; observe “gun metal”-colored kidneys at necropsy.

Treatment:

• Management: Rarely successful, use GI sedatives and treatments for shock.
• Prevention: Monitor dietary copper and molybdenum levels, and use supplements to manage copper absorption.

Pearls:
Sheep are uniquely sensitive to copper, with toxicity often triggered by stress events. Proper diet management is crucial for prevention.

10. Polled Intersex Syndrome (PIS)

Classic Case:
Affects breeds like Toggenburg, Saanen, and Alpine goats, presenting as male phenotype with female genotype and underdeveloped reproductive structures.

Diagnosis:

• Tools: Thorough physical examination.

Treatment:

• Management: Cull affected animals and avoid breeding polled bucks.

Pearls:
Polledness is an autosomal dominant trait, while intersexism is recessive and occurs only in polled females. PIS is rare in cattle and sheep.

11. Pizzle Rot (Enzootic Posthitis and Vulvitis)

Classic Case:
Affects castrated males with preputial swelling and scabs around the orifice. Females show vulval swelling and ulcers.

Diagnosis:

• Etiology: Corynebacterium renale infection.
• Tools: Clinical signs and culture.

Treatment:

• Management: Isolate affected animals, clean the prepuce, and administer antibiotics.

Prevention:
Manage diet to reduce protein intake and monitor preputial hair length to prevent urine trapping.