Small ruminants make up roughly 5% of the NAVLE — about 18 questions across 360. That does not sound like a lot until you realize that 18 missed questions can be the difference between passing and failing. The good news: the NAVLE tests a predictable set of small ruminant conditions. Learn these well and you can bank most of those 18 points in a single focused study week.
Top Conditions by Frequency
Small Ruminant Conditions Most Commonly Tested on NAVLE
Caseous Lymphadenitis (CLA)High frequency
Pregnancy ToxemiaHigh frequency
Urolithiasis (Obstructive)High frequency
Enterotoxemia (Clostridium perfringens)Medium frequency
Ovine Progressive Pneumonia (OPP)Medium frequency
Caprine Arthritis Encephalitis (CAE)Medium frequency
Scrapie, Contagious Ecthyma, ListeriosisLower frequency
Sheep vs. Goats: Key Differences the NAVLE Tests
Sheep (Ovine)
- OPP — lentivirus, progressive pneumonia, no treatment
- Scrapie — prion disease, notifiable, sheep rub against fences
- Pregnancy toxemia — late gestation ewes with twins/triplets
- CLA — Corynebacterium pseudotuberculosis, thick caseous pus
- Enterotoxemia — C. perfringens type D (pulpy kidney), overeating
- Urolithiasis less common than in wethers/bucks
Goats (Caprine)
- CAE — lentivirus, arthritis in adults, encephalitis in kids
- Urolithiasis — castrated males (wethers/bucks), ammonium phosphate crystals
- CLA — same pathogen, also causes internal abscess in lungs/liver
- Contagious ecthyma (Orf) — parapoxvirus, proliferative lip lesions, zoonotic
- More browse feeders — different nutritional disease profile than sheep
- Pregnancy toxemia same as sheep when carrying multiple kids
High-Yield Condition Reference
| Condition | Key Signalment | Classic Presentation | Treatment |
|---|
| CLA | Any age, sheep or goat | Firm subcutaneous abscess, thick cream/green layered pus | Drainage + penicillin; vaccine available |
| Pregnancy Toxemia | Late-gestation ewe/doe, multiple fetuses | Depression, recumbency, star-gazing, hypoglycemia | IV/oral glucose, propylene glycol, C-section if severe |
| Urolithiasis | Castrated male goat on high-grain diet | Straining, tail flagging, no urine, crystalline deposits on prepuce | Tube cystotomy or urethrostomy; adjust Ca:P ratio |
| Enterotoxemia | Lambs/kids after feed change | Sudden death or bloody diarrhea, convulsions | C. perfringens antitoxin; prevention via CDT vaccine |
| OPP | Adult sheep >2 years | Progressive dyspnea, weight loss, no fever, normal WBC | None — cull infected animals, test-and-remove |
| CAE | Kids (encephalitis) or adult goats (arthritis) | Kids: ascending paralysis; Adults: carpal joint swelling, hard udder | None — test-and-cull, separate kids from does at birth |
| Contagious Ecthyma | Young lambs/kids | Proliferative pustules on lips/muzzle, zoonotic (wear gloves) | Self-limiting; supportive care; live attenuated vaccine |
NAVLE PearlUrolithiasis in small ruminants almost always involves a castrated male (wether or buck) on a high-concentrate diet. The Ca:P imbalance (ideal ratio 2:1) causes ammonium phosphate crystal formation. The NAVLE will give you the diet history and ask for the management change — add calcium, reduce grain, acidify urine with ammonium chloride supplementation.
Classic NAVLE TrapOPP and CAE are both lentiviruses causing progressive disease with no treatment. Students confuse them because the presentation overlaps. The key: OPP = lungs (progressive pneumonia in sheep). CAE = joints and nervous system (arthritis in adult goats; encephalitis in kids). Different species, different tropisms.
Camelidae: The 1–2 Question Bonus
Camelidae (llamas and alpacas) appear on the NAVLE occasionally — usually 1–2 questions. The highest-yield topics: hepatic lipidosis (similar to pregnancy toxemia — off-feed camelids in late gestation or stress), neonatal isoerythrolysis when crossbreeding llamas with guanacos (rare but high-yield when tested), and basic herd health (CDT vaccination, halter training stress, basic nutrition). One anatomical point: camelids have a three-compartment stomach, not a four-compartment rumen like cattle.
For structured weekly preparation, the study roadmap places small ruminants in Week 11 of the 3-month NAVLE plan, after large animal species, giving you appropriate context before tackling these conditions.