12 Common Sheep Diseases: Symptoms, Treatment & Prevention

Keeping your flock healthy requires knowing what to watch for. This guide covers the most common sheep diseases, how to recognize them early, and most importantly, how to prevent them. A healthy flock starts with informed shepherding.

Emergency Warning Signs

Contact your vet immediately if you see:

• Sheep down and unable to rise
• Severe bloating (distended left side)
• Bloody diarrhea
• Labored breathing
• High fever (over 104°F)
• Seizures or head pressing
• Multiple animals affected suddenly

Internal Parasites

Haemonchus contortus (Barber Pole Worm)

The #1 killer of sheep — this blood-sucking parasite causes severe anemia.

Symptoms:

• Pale gums, eyelids, and mucous membranes
• Bottle jaw (swelling under jaw)
• Weight loss despite good appetite
• Weakness and lethargy
• Sudden death in severe cases

Diagnosis:

• FAMACHA scoring (eyelid color check)
• Fecal egg count

Treatment:

• Targeted deworming based on FAMACHA/FEC
• Supportive care (iron, B vitamins)
• Severe cases may need blood transfusion

Prevention:

• Rotational grazing
• Don’t overstock pastures
• Avoid grazing wet areas
• FAMACHA monitoring
• Breed for resistance
• Smart drenching (not routine)

Other Internal Parasites

Parasite	Location	Key Symptoms
Brown stomach worm	Abomasum	Diarrhea, weight loss
Liver flukes	Liver	Anemia, bottle jaw
Lungworms	Lungs	Coughing, pneumonia
Tapeworms	Intestines	Usually minor impact

Foot Problems

Foot Rot

Highly contagious bacterial infection causing severe lameness.

Symptoms:

• Severe lameness (often multiple feet)
• Foul smell from hooves
• Separation of hoof wall from sole
• Red, raw tissue between toes
• Reluctance to move

Treatment:

• Isolate affected animals
• Aggressive hoof trimming
• Foot bath (zinc sulfate or copper sulfate)
• Antibiotics for severe cases
• Keep feet dry

Prevention:

• Quarantine new animals (30 days minimum)
• Regular hoof trimming
• Dry, clean environment
• Cull chronically infected animals
• Foot bath after shows/sales

Foot Scald

Milder condition than foot rot, often a precursor.

Symptoms:

• Mild lameness
• Redness between toes
• No foul smell
• Usually responds quickly to treatment

Treatment:

• Foot bath
• Dry environment
• Usually resolves without antibiotics

Respiratory Diseases

Pneumonia

Common, especially in young lambs and stressed sheep.

Symptoms:

• Coughing
• Nasal discharge (clear to purulent)
• Labored breathing
• Fever (103-106°F)
• Loss of appetite
• Droopy ears
• Separation from flock

Treatment:

• Antibiotics (consult vet)
• Anti-inflammatories
• Supportive care (shelter, hydration)
• Isolate from flock

Prevention:

• Good ventilation in barns
• Minimize stress
• Don’t overcrowd
• Proper colostrum intake
• Vaccine programs (where applicable)

Metabolic Diseases

Pregnancy Toxemia (Ketosis)

Occurs in late pregnancy when ewes can’t meet energy demands.

Risk factors:

• Multiple fetuses (twins, triplets)
• Overweight or underweight ewes
• Poor nutrition in late pregnancy
• Stress

Symptoms:

• Occurs 2-4 weeks before lambing
• Separation from flock
• Reluctance to eat
• Sweet/acetone breath
• Stargazing, head pressing
• Grinding teeth
• Down and unable to rise
• Coma and death if untreated

Treatment:

• Propylene glycol or glycerol orally
• IV dextrose in severe cases
• Induce lambing or C-section may be needed
• Calcium/magnesium supplementation
• Vet emergency if ewe goes down

Prevention:

• Proper body condition at breeding (not too fat, not too thin)
• Increase energy in last 6 weeks of pregnancy
• Ultrasound to identify multiple pregnancies
• Keep ewes active
• Reduce stress

Milk Fever (Hypocalcemia)

Calcium deficiency around lambing, especially with multiple lambs.

Symptoms:

• Occurs within 24-48 hours of lambing
• Weakness, staggering
• Muscle tremors
• Unable to rise
• Cold ears
• Bloat

Treatment:

• Calcium borogluconate IV or subcutaneous
• Warm and protect down ewe
• Often responds rapidly to treatment

Prevention:

• Proper mineral supplementation
• Avoid high-calcium diets before lambing
• Gradual feed changes

Clostridial Diseases

Enterotoxemia (Overeating Disease)

Caused by Clostridium perfringens types C and D.

Symptoms:

• Often sudden death
• Diarrhea (sometimes bloody)
• Convulsions
• Abdominal pain
• Found dead without prior signs

Risk factors:

• Sudden diet changes
• Heavy grain feeding
• Lush pasture
• Weaning stress

Treatment:

• Often fatal before treatment possible
• Antitoxin if caught early
• Supportive care

Prevention:

• CD&T vaccination (most important vaccine)
• Vaccinate ewes 4 weeks before lambing
• Vaccinate lambs at 4-6 weeks, booster 3-4 weeks later
• Gradual diet changes
• Limit grain intake

Tetanus

Caused by Clostridium tetani entering wounds.

Symptoms:

• Stiffness
• Lockjaw (difficulty eating)
• “Sawhorse” stance
• Hypersensitivity to sound/touch
• Seizures
• Usually fatal once advanced

Treatment:

• Antitoxin and antibiotics if caught early
• Sedation and supportive care
• High mortality rate

Prevention:

• CD&T vaccination
• Vaccinate before procedures (docking, castrating)
• Clean equipment and wounds

Digestive Problems

Bloat

Rapid gas accumulation in the rumen—life-threatening emergency.

Types:

• Frothy bloat: From legume pastures (alfalfa, clover)
• Free gas bloat: From obstruction or other causes

Symptoms:

• Distended left side
• Difficulty breathing
• Restlessness, then depression
• Grunting
• Death within hours if untreated

Treatment:

• Emergency! Contact vet immediately
• Walk the animal
• Stomach tube to release gas
• Anti-bloat oils
• Trocar in life-threatening cases

Prevention:

• Introduce legume pastures gradually
• Don’t graze wet alfalfa
• Mixed grass-legume pastures
• Feed dry hay before legume grazing

Acidosis (Grain Overload)

Occurs when sheep consume too much grain too quickly.

Symptoms:

• Occurs 12-36 hours after overfeeding
• Off feed
• Staggering, weakness
• Diarrhea
• Dehydration
• Rapid heartbeat

Treatment:

• Remove grain access
• Baking soda drench
• Probiotics
• IV fluids in severe cases
• Thiamine supplementation

Prevention:

• Secure feed storage
• Gradual grain increases (10% every 3 days)
• Limit individual grain portions

Skin and External Problems

External Parasites

Parasite	Signs	Treatment
Keds (sheep tick)	Rubbing, poor fleece	Pour-on or injectable
Lice	Itching, wool damage	Insecticide treatment
Mites (scab)	Crusty skin, wool loss	Ivermectin, quarantine
Blowflies (strike)	Maggots in wool/wounds	Clean, treat, prevent

Flystrike (Myiasis)

Maggot infestation—more common in warm, wet conditions.

Symptoms:

• Restlessness, tail wagging
• Biting at wool
• Wet, stained wool
• Foul smell
• Maggots visible on closer inspection
• Rapid deterioration

Treatment:

• Shear affected area
• Remove all maggots
• Clean and treat wounds
• Systemic antibiotics if severe
• Anti-inflammatories

Prevention:

• Crutching (dagging) to keep rear clean
• Fly prevention products
• Prompt treatment of wounds/diarrhea
• Reduce fly populations

Infectious Diseases

Caseous Lymphadenitis (CL)

Chronic bacterial infection causing abscesses.

Symptoms:

• Abscesses in lymph nodes (neck, shoulder, flank)
• Thick, green-white pus
• Weight loss over time
• Internal form can affect lungs

Treatment:

• No cure
• Isolate affected animals
• Do NOT lance abscesses (spreads disease)
• Cull from breeding flock

Prevention:

• Buy from CL-free flocks
• Test new arrivals
• Don’t share equipment
• Vaccine available (discuss with vet)

Johne’s Disease

Chronic wasting disease affecting intestines.

Symptoms:

• Chronic weight loss
• Normal to increased appetite
• No response to deworming
• Usually affects adults
• Diarrhea (sometimes)

Diagnosis:

• Blood test (ELISA)
• Fecal culture

Treatment:

• No treatment
• Manage and cull

Prevention:

• Buy from Johne’s-free flocks
• Test breeding animals
• Don’t mix young stock with adults
• Separate at-risk lambs early

Prevention Checklist

Vaccination Program

Vaccine	Who	When
CD&T	All sheep	Annual; ewes 4 weeks before lambing
CD&T	Lambs	4-6 weeks old, booster 3-4 weeks later
Rabies	Optional	Where required

Biosecurity Basics

• Quarantine new animals 30 days
• Don’t share equipment between farms
• Clean and disinfect trailers
• Isolate sick animals immediately
• Limit visitor access to sheep areas
• Change clothes/boots between farms

Routine Health Monitoring

• Daily observation of all animals
• Weekly FAMACHA checks in parasite season
• Monthly body condition scoring
• Quarterly fecal egg counts
• Annual vaccination
• Regular hoof trimming

Working with Your Veterinarian

Finding a Good Sheep Vet

• Check AASV (American Association of Small Ruminant Practitioners)
• Ask other sheep farmers
• Look for large animal or mixed practice vets
• Establish relationship BEFORE emergencies

When to Call the Vet

• Any emergency symptoms (bloat, down sheep, seizures)
• Multiple animals affected
• Unknown illness
• Not responding to treatment
• Before major procedures
• Annual flock health planning

Conclusion

Preventing disease is far easier than treating it. Focus on:

1. Proper nutrition
2. CD&T vaccination
3. Strategic parasite management
4. Biosecurity practices
5. Daily observation
6. Good working relationship with your vet

Most common sheep diseases are preventable with good management. Know the warning signs, act quickly, and don’t hesitate to call for help.

Need to find sheep or connect with experienced breeders? Browse our directory to find farms in your area who can share their health management practices.

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