Disease of Sheep & Goats - Preventive Health

Disease of Sheep & Goats: Preventive Health

General Considerations

  • Sheep and goats are managed under varying conditions, which can be categorized as:

    • Intensive management

    • Environmental conditions affecting health

    • Density of population in the environment

  • Importance of educating the owner about the following:

    • Observations of animal behavior and health

    • Identification methods for individual animals

    • Record-keeping for health monitoring

Diseases of Sheep

Clostridial Diseases

  • Disease Types:

    • Enterotoxemia

    • Tetanus

    • Caseous Lymphadenitis

    • Contagious Ecthyma

    • Foot Rot

    • Johne’s Disease

    • Q Fever

    • Maedi-Visna

Clostridial Diseases
Enterotoxemia

  • Disease Types:

    • Type B: Lamb dysentery

    • Type C: Lamb struck, hemorrhagic enterotoxemia, bloody scours

    • Type D: Pulpy kidney, overeating disease

  • Agent: Clostridium perfringens (Types B, C, D)

  • Transmission:

    • Normally present as flora in the environment.

    • Overgrowth occurs due to heavy carbohydrate (CHO) diet and gut stasis.

  • Signs:

    • Appears in lambs/kids aged 4-10 weeks.

    • Symptoms are often acute and fatal, including diarrhea and neurological signs.

    • Post-mortem (PM) findings include fluid in the gastrointestinal tract (GI) and necrotic kidneys.

  • Comments:

    • Annual vaccination of dams prior to lambing/kidding.

    • Vaccination for lambs/kids at 2-4 week intervals, starting at 8 weeks.

Clostridium perfringens - Type B (Lamb Dysentery)

  • Characteristics:

    • Acute and rapidly fatal in lambs aged 2-10 weeks.

    • Initially affects strong lambs under 2 weeks of age.

    • Symptoms include listlessness and recumbence.

  • Severe inflammation observed during PM examination.

Clostridium perfringens - Type C

  • Characteristics:

    • Causes hemorrhagic enteritis during the first week of life, leading to bloody infections of the small intestine (SI).

    • Disease associated with feed changes and digestive upset, leading to toxin production.

    • An antitoxin is available but is ineffective in lambs.

  • Note: Administer to ewes 1 month prior to lambing for best efficacy.

Clostridium perfringens - Type D (Pulpy Kidney)

  • Characteristics:

    • Known as overeating disease affecting the largest and fastest-growing lambs.

    • Caused by sudden feed changes resulting in toxin production.

    • Ultimately leads to pulpy kidney—characterized by an excess of pericardial fluid and localized enterotoxemia in the SI.

Clostridial Diseases - Tetanus

  • Disease: Tetanus, also known as "lockjaw"

  • Agent: Clostridium tetani (anaerobic bacteria)

  • Transmission:

    • Infection through wounds, surgical sites, or needles.

    • Common post-docking of tails and castrating.

  • Signs:

    • Muscular stiffness, saw-horse stance, lockjaw, prolapse of the third eyelid, hyperesthesia, labored breathing.

  • Treatment:

    • Administer antitoxin and antibiotics.

  • Comments:

    • Routine vaccination as per veterinarian recommendations.

    • Distinction made between toxoid (vaccine) vs. antitoxin (for wounded animals).

Caseous Lymphadenitis

  • Etiology: Infection stemming from soil or mechanically caused wounds.

  • Agent: Corynebacterium pseudotuberculosis (bacteria)

  • Transmission:

    • Marked lymph node enlargement with a "cheesy" lamellated "onion ring" appearance.

    • Isolation of affected animals is crucial.

    • Bacteria enter through open wounds or mucous membranes.

  • Signs:

    • May exhibit signs of emaciation and unthriftiness.

    • Abscesses can develop on internal organs.

    • If deep lymph nodes are affected, they may rupture, contaminating the environment.

  • Comments:

    • Use of Glanvac 6® is recommended.

    • Culling of infected animals is advised; vaccines are available for sheep but not recommended for goats.

Contagious Ecthyma (Orf)

  • Alternative Name: Also called Sore mouth disease

  • Agent: Parapoxvirus genus (virus)

  • Transmission:

    • Spread through direct contact and fomites.

    • Lesions can develop on teats, causing painful nursing, which may lead to premature weaning and mastitis.

  • Precautions:

    • Always wear gloves when vaccinating to prevent human infection.

  • Availability of Vaccine:

    • Not available in Canada; other countries use it applied in non-wool areas, such as inside the ear, to prevent spreading to the mouth.

    • Vaccine is a live virus and poses infection risk to humans.

Foot Rot

  • Importance of Regular Care:

    • Regular hoof trimming essential to prevent disease.

  • Pathogens:

    • Gram-negative anaerobes:

    • Fusobacterium necrophorum: A normal inhabitant of soil and sheep manure.

    • Dichelobacter nodosus: Natural inhabitant of the large intestine of ruminants.

    • Together, they can cause disease if they gain entry into the interdigital area due to irritation.

  • Image of Severe Case:

    • Example includes decayed tissue at the heel and separation of the hoof wall.

Johne’s Disease

  • Agent: Mycobacterium avium (subspecies: paratuberculosis)

  • Global Issue: More common in cows, but affects sheep.

  • Transmission: Fecal-oral route via contaminated feed.

  • Characteristics:

    • Long prepatent period with signs typically not visible until 2 years of age.

    • Diarrhea generally occurs at the end stage of the disease.

    • Contaminates pasture and primarily affects intestines but manifests as a wasting disease in sheep.

Q Fever (Coxiellosis)

  • Etiological Agent: Coxiella burnetii (bacteria)

  • Reservoirs: Found in cattle, sheep, goats, and other species.

  • Transmission:

    • Via aerosols from infected birth fluids and ruminant placentae.

    • Can also be transmitted through wool, hides, soil, milk, urine, and feces.

  • Resistance: The bacterium is resistant to high temperatures, sunlight, and several disinfectants.

  • Implications for Humans: Transmissible, especially to immunocompromised individuals; signs can include fever and respiratory infections.

Scrapie

  • Agent Type: Prion disease affecting primarily sheep but can affect goats.

  • Characteristics:

    • Causes spongiform encephalopathies affecting the central nervous system (CNS).

    • Clinical signs include weight loss, severe itching with rubbing, wool pulling, biting behaviors, and a distinctive "bunny hop" movement in affected sheep.

  • Treatment: None available for Scrapie.

Pneumonia

  • Causes:

    • Multiple etiological agents including bacteria, mycoplasma, and viruses.

    • Often seen in respiratory tracts of otherwise healthy lambs who experience environmental stressors.

  • Treatment Approach: Focus on addressing causes of secondary infections.

  • Specific Conditions:

    • Maedi-Visna: Progressive pneumonia leading to wasting disease; fatal.

    • CAE (Caprine Arthritis Encephalitis in goats): Another serious condition affecting goats.

Pregnancy Toxemia (Ketosis)

  • Overview: More frequent in sheep than goats.

  • Affected Groups: Fat or thin animals carrying twins.

  • Mechanism: Ewes may be unable to meet nutritional demands as fetuses occupy more space, leading to decreased energy intake.

  • Metabolic Shift: When fatty acids are metabolized at high rates, ketone bodies are produced, leading to symptoms such as:

    • Depression

    • Anorexia

    • Weakness

    • Inability to stand

Terrestrial Animal Diseases

  • Reportable Diseases:

    • Must be reported immediately upon discovery.

  • Notifiable Diseases:

    • Required to be reported annually for proper monitoring and control.

Vaccinations

  • Recommended Vaccines:

    • Clostridium vaccines for:

    • Enterotoxemia (Clostridium perfringens Types C and D)

    • Tetanus (Clostridium tetani)

    • Caseous Lymphadenitis

    • Contagious Ecthyma (Orf)

    • Foot Rot (noted that results take 2-3 years)

    • Rabies

    • Lamb Pneumonia (PI-3)

  • Other Clostridial Disease Vaccines:

    • Include vaccines for malignant edema, black leg, and various Clostridium species (e.g., Clostridium septicum, Chauvoei, Novyi, Sordellii, Hemolyticum).

Vaccination Programs

  • Customization of Programs: Each vaccination program must be tailored to the individual operation of the producer.

  • Understanding: Producers should comprehend the purpose of each vaccine and its significance for herd health.

  • Considerations: The availability of a vaccine for a specific disease does not automatically mean it should be used. Risk factors and other control measures should be assessed.

  • Clostridial Vaccines: Generally the only vaccines recommended on a broad basis for sheep and goats. Timing of vaccinations for clostridial diseases and tetanus is critical.

Vaccination Timing and Recommendations

  • Pregnant Sheep and Goats: 2-4 weeks prior to delivery.

    • Vaccines covered: Clostridium perfringens C & D; Tetanus.

  • Kid Goats: At lambing/kidding.

    • Should receive SE/vitamin E to prevent white muscle disease.

  • New Lambs:

    • 2 weeks old: 300 I.U. of tetanus antitoxin if the dam was not vaccinated during gestation.

    • 30 days after lambing/kidding: booster, followed by a second booster at 45 days for Clostridium perfringens C & D, and Ovine ecthyma.

  • Ewes and Does: 60-30 days pre-breeding.

    • Vaccines: Campylobacter fetus-jejunum bacterin, Chlamydia psittaci ewe vaccine, and Clostridial 8-way.

  • Bucks and Rams: 30-60 days pre-breeding for Clostridial 8-way covering eight clostridial strain bacterial diseases breaking down to skin lesions and abscesses.

Conclusion

  • Comprehensive knowledge and application of preventive health measures, especially vaccination programs, play vital roles in managing sheep and goat diseases. Educating producers and ensuring the correct implementation of health practices are essential for sustaining healthy livestock.