Monday, December 17, 2012

Cause of Thin Goats Examined

University of Missouri veterinarian John Middleton said thin goats are usually the result of four main diseases.
Middleton spoke at the recent Missouri Livestock Symposium in Kirksville. MU Extension and the Missouri Livestock Symposium Committee organize the annual event.

One of the main causes is gastrointestinal parasites. Internal parasites are cyclical, shedding eggs in the host animal’s manure that hatch and develop into infective larvae, which can be ingested when animals graze pasture contaminated by manure.

Signs of infection include poor growth, decreased weight gain or loss of weight, reduced milk production, diarrhea, anemia as exhibited by pale mucous membranes around the eyelids, lower jaw swelling known as bottle jaw, underbelly swelling and death.

Examination of feces is the best way to diagnose parasite load and determine treatment, Middleton said. Strategic deworming protocols provide the best results; information is available from veterinarians or extension specialists.

Parasites tend to become resistant to dewormers over time, so Middleton suggests deworming with one product until signs of resistance show. He recommended against alternating dewormers.

He also said that animals should not be allowed to graze pastures to grass levels below 2 inches in height, which would increase exposure to infective parasite larvae. However, grass that is too tall may increase parasite populations by blocking sunlight and maintaining humid conditions at the base of the grass. Grass should be 2-6 inches in height. “Appropriate pasture management will help decrease host exposure and decrease the need for deworming,” he said.

Coccidia infestation of goats is common in the spring and is seen most in young goats. Symptoms include severe diarrhea, pneumonia-like symptoms, depression, weight loss, anemia, loss of appetite and even death. The disease can be controlled by adding coccidiostats to the feed or water.

Johne’s disease is a chronic disease that causes a wasting body condition with or without diarrhea. Young animals are thought to be more susceptible to infection with the disease-causing organism, Mycobacterium avium paratuberculosis, than adults and can acquire the organism by the fecal-oral route, through milk and possibly across the placenta in utero. The incubation period of the disease is very long, with animals infected as kids often not showing clinical signs until adulthood. Chronic weight loss despite a healthy appetite is usually the main indicator of the disease.

There is no effective treatment, and goat owners can best prevent this disease by maintaining a “closed herd.” The organism can survive in manure for more than a year. Middleton said it is estimated as many as 50 percent of boar goat herds in Missouri may have this disease.

Caprine arthritis encephalitis virus can affect multiple organ systems in goats, with arthritis being a common manifestation of the disease in older goats. Arthritis can occur in more than one joint. Infection usually occurs by the kid ingesting colostrum or milk from an infected dam. Infection is lifelong and the various disease manifestations show up at different ages. Kids tend to be affected by nervous system dysfunction while adults tend to be affected by arthritis, pneumonia, hard udder or chronic wasting. Some goats may never show clinical symptoms. There is no treatment and affected animals are a source of infection to others, so culling of infected animals is recommended, Middleton said. It may take three or four years before symptoms appear in this painful disease.

Caseous lymphadenitis is a devastating disease, more common in sheep than goats. It causes abscesses under the skin in various lymph nodes and can also cause internal abscesses. External abscesses should not be opened in the vicinity of other animals. If necessary, quarantine infected goats to prevent environmental contamination and infection of other animals.

Middleton also warned against putting out certain types salt blocks for small ruminants. Horse and cattle mineral blocks often contain higher concentrations of copper, which can be toxic to sheep and goats. Mineral supplements and salt blocks should be specifically labeled for sheep and goats.
 (By Linda Giest, MU Senior Information Specialist)

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