Dr. Steve Parish
Sheep and Goats
Introduction:
On a worldwide basis sheep and goats are probably the most important of all domesticated animals from a standpoint of food and fiber. Many countries and their indigenous populations rely heavily on these animals in all aspects of daily life. In the United States, the number of sheep has steadily decreased in the later half of this century. The western States were the home of extensive ‘nomadic’ sheep operations utilizing public lands for grazing. Millions of animals were grazed on a year around basis for the production of meat and wool. With the decreased use of public lands for grazing, many of the original sheep operations have ceased to exist. New Zealand, Australia and Argentina are now the major producers of sheep in the world and are the prime suppliers on an international fiber and meat market. Currently in the US, while some large operations still exist, most sheep and goat production units are quite small. These range from small farm flocks to some modern goat dairies. In general, most sheep and goats in the Pacific Northwest are of the small farm flock type. Uses include dairy products, minor meat production, production of purebred animals and the show industry. A sideline of the goat industry has been the boom in the production of pigmy goats as pets. Many are maintained because of the small stature and friendly nature.
Production cycle:
Reproduction:
- Sheep and goats are seasonal polyestrus
- Some out of season breeding is possible
- Greatest fertility during late fall months in our area in males and females.
- Gestation is approximately 150 days
- Placentation – Cotyledonary
- Twinning common
Abortion diseases:
Late term abortion, stillbirth or the birth of weak lambs or kids characterizes many of the following.
Enzootic Abortion – Chlamydia
- Carrier and aborting females are the source of infection to other susceptible animals in the herd.
- Abortion is caused by a slowly developing placentitis.
- Exposure late in one pregnancy may lead to abortion the following pregnancy.
- Abortion often confers immunity
- A vaccine is available
Campylobacter (Vibrionic abortion)
- Carrier animals are the source of infection
- Transmission is oral by contact with infectious discharges from a carrier or aborting female
- Abortion is due to placental damage
- A vaccine is available
Toxoplasmosis
- The cat is the definitive host and the agent is spread via the contact with cat feces orally.
- Only non-immune females abort.
- Placentitis is the cause of the abortion
- No vaccine
Leptospirosis
- Numerous serotypes of ‘Lepto’ are associated with abortion in sheep and goats. These are generally the same as the ones seen in cattle
- Abortion is usually associated with fetal death.
- Bovine vaccines can be used in small ruminants
Salmonella
- Certain strains of Salmonella have been associated with abortion in small ruminants
- Abortion can occur at any time, but is usually late.
Pregnancy diseases other than abortion
Pregnancy toxemia
- Negative energy balance occurring in late pregnancy
- Females affected usually are pregnant with twins or triples
- Often affected females are in excess body condition going into late pregnancy
- The disease is characterized by depression, anorexia, weight loss, recumbency and death.
- Concurrent diseases such as foot rot can be predisposing.
- Treatment may include: glucose, glucose precursors, steroids and termination of pregnancy.
Hypocalcemia
- Occurs in small ruminants both before parturition and after. Before is related to fetal demands and after to lactational demands for calcium.
- The disease is characterized by muscular weakness, anorexia, depression, recumbency and death
- Proper calcium supplementation and diet are important for control of the syndrome.
Mastitis
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Mastitis, infection of the mammary gland is a common situation in sheep and goats.
- Mastitis is a major cause of premature culling and neonatal wastage.
- New infections most commonly occur either a ‘dry off’ time or at the beginning of lactation.
- Most infections are ascending via the teat.
- Common bacteria, including Staphylococcus, Streptococcus, Pasteurella and Coliforms, are often isolated.
- Treatment of acute cases may involve frequent ‘stripping’ of the gland, intramammary antibiotics, anti-inflammatory drugs and systemic antibiotics.
- The use of ‘dry cow’ treatments at the end of lactation is wise in both species.
- Chronic cases rarely fully recover and are usually culled.
Parturition
- The gestation period of sheep and goats is approximately 150 days.
Vaccination programs
- Vaccination programs for adults can include agents against numerous diseases. Herd history will determine which are necessary.
Foot rot, abortion diseases, Clostridial diseases (CD/T) and Sore Mouth
Newborn lambs and kids
Causes of death loss
Dystocia
Starvation/hypothermia
White muscle disease/Selenium deficiency
Infectious diseases
Diarrhea
- E.coli, salmonella and viral causes are noted
- The clinical picture is the same as calves and llamas
Pneumonia
- Pneumonia is common in young small ruminants and is associated with Mycoplasma sp. and Pasteurella sp.
- The disease may be characterized by sudden death or severe respiratory distress followed by debility and possible death if not recognized and treated promptly.
Enterotoxemia
- As with llamas, small ruminants are susceptible to enteric Clostridial infections.
- Control is via vaccination
Passive transfer of immunoglobulins
Identical to that describe with calves and llamas
Lambs can receive goat colostrum is necessary. Bovine colostrum may cause a hemolytic crisis in some lambs.
Common procedures
Castration/tail docking/dehorning
Best accomplished in the first 2-3 weeks of life
Weaning and feeding of lambs/kids
- Lambs are often marketed directly at weaning, however they can be weaned at 6-8 weeks and successfully raised in a ‘feedlot’ environment.
- Lambs and kids should be revaccinated at weaning for Clostridial disease (CD/T)
Raising orphan lambs/kids
- Lambs and kids can be successfully raised ‘on the bottle’
- Young animals are susceptible to digestive upsets from overfeeding.
- Careful dietary considerations are necessary to successfully raise orphan lambs and kids.
- By 6-8 weeks they should be totally weaned off milk and be consuming high quality concentrates and hay.
Feeding and nutrition for maintenance and production
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Feeding of the herd depends on the production cycle and BCS assessment.
- Proper nutrition is the key to successful production and disease prevention.
- Many feed sources are used and the animals are found to be very thrifty and adaptable.
Body condition scoring
- A scale of 1-5 is used in sheep and goats, judging the degree of fullness in the lumbar region and over the ribs.
- Animals are most productive in the 3-3.5 range.
Lameness in sheep and goats
Lameness in small ruminants is commonly associated with foot pathology.
Conditions seen include:
Foot rot
- A contagious, infectious condition causes by Dicleobactera nodosa and Fusobacterium necrophorum.
- Carrier animals are the source of the first agent.
- Transmission occurs during periods of warmth and moisture.
- Treatment involves foot trimming, foot baths and antibiotics
- Vaccines are available
Foot scald
- An interdigital disease similar to foot rot in cattle.
- Associated with moist environment and non-foot rot stains of Dicleobacterium.
- Foot baths and dry environments are curative.
- Foot abscess
- An abscess syndrome affecting the hind foot most commonly.
- Occurs secondary to foot scald
- Often seen in late pregnant ewes and is a cause of pregnancy toxemia
Other lameness conditions involve the musculoskeletal system
Diseases of adults
Thin ewe/doe syndrome
The following are common causes of debilitation of adult sheep and goats
Abscesses
- Internal and external abscesses caused by Arcanobacter and Corynebacterium species occur most commonly.
- Corynebacterium pseudotuberculosis (caeceous lymphatenitis, CL) is a contagious abscess disease between animals.
- Arcanobacter is an opportunist.
- Drainage from an infected area is infectious to other animals.
- A vaccine is available for CL.
OPP/CAE
- These are retroviral diseases of sheep (OPP) and goats (CAE).
- OPP is a chronic inflammatory disease of the lung leading to eventual suffocation.
- CAE is a disease characterized by the development of chronic arthritis and debility
- Both diseases have long incubation periods, often 2-3 years
- Transmission for both generally involves the transmitting of a similar retrovirus via colostrum to the newborn from its carrier mother.
- In both species, frequently there is an infiltration of ‘scar tissue’ into the udder as the disease progresses.
- Neurologic involvement is seen in both syndromes
- There is no treatment for either disease.
- Prevention involves culling carrier animals, colostral and milk management.
Johne’s disease
- A chronic wasting disease characterized by replacement of the gut lining by ‘scar’ tissue leading to a malabsorption syndrome.
- The causative agent is Mycobacterium paratuberculosis
- Transmission occurs from infected animals to young animals in the flock as the are most susceptible.
- Incubation is two to three years before clinical signs of wasting, diarrhea and eventual death
- There are no approved treatments.
Scrapie
- A prion disease of both sheep and goats leading to degenerative changes in the brain and eventual death of the animal.
- This disease is in the same family of diseases as ‘Mad Cow Disease and CJD of humans.
- There is no transmission of scrapie to humans.
- Transmission occurs from genetically susceptible individuals infected with the agent to other genetically susceptible individuals.
- Transmission mostly likely occurs naturally before or shortly after birth.
- Diagnosis is make through lymphoid biopsy/monoclonal antibodies or histology of the brain.
- There is no treatment.
Parasite problems and control programs (Covered in other sections)
Internal parasites (intestinal and stomach worms) are the most common problem parasites in sheep and goats.
Last edit February 11, 2000