Goat kids harbor several species of coccidia but not all have clinical coccidiosis (see Coccidiosis). Signs are diarrhea or pasty feces, loss of condition, general frailness, and failure to grow. In peracute cases, the goat may die with no signs. Rotating all the kids through 1 or 2 pens is dangerous; adult goats shed coccidia and infect the newborn. As infection pressure builds up in the pens, morbidity in kids born later is increased. To help prevent coccidiosis in artificially reared dairy goats, the kids should be put in small, age-matched groups in outside portable pens that are moved to clean ground periodically. Eradication is not feasible, but infection can be controlled through good management practices. Coccidiostats added to the water or feed are adjuncts to a management control program and not substitutes. Chronic coccidiosis is one of the main causes of poor growth in kids and is responsible for the uneconomical practice of delaying breeding for a year until the goat has reached adequate size (70 lb [32 kg] for dairy breeds). In Angora goats kept extensively, the problem is seen at weaning, when the kids are kept in smaller lots and fed supplement on the ground.
In pastured and free-ranging goats, helminthiasis can assume great clinical significance. GI nematodiasis, liver fluke infestation, and lungworm infections all may be seen. Age-related resistance to parasitism in goats is weak relative to other ruminants. Although most common in yearlings during their first season at pasture, clinical disease may be seen in adults as well. Poor growth, weight loss, diarrhea, a scruffy hair coat, signs of anemia, and intermandibular edema (bottle jaw) may be seen with GI parasitism or liver fluke disease. Haemonchus contortus infection has emerged as a major constraint in the expanding meat goat industry in the southeastern USA. Persistent coughing in late summer and autumn is the usual presentation of lungworms; secondary bacterial pneumonia with fever is a common sequela. Parasitism is insidious on hobby farms where the problem may not exist for several years and then suddenly explodes as goat numbers continue to increase and pastures become overstocked. Tapeworm proglottids are often noted in goat feces by owners. Although tapeworms are not generally considered to be of clinical importance, their discovery can be used to review the subject of helminthiasis with owners and develop an overall parasite control program (see Gastrointestinal Parasites of Sheep and Goats).
Clostridium perfringens type D can be fatal, and it is not always associated with the classic “change in quality and quantity of feed.” In problem herds, vaccination every 4–6 mo may be necessary, because goats may not maintain protective immunity as long as sheep or cattle when given the same commercial vaccines. Vaccination prevents the acute death syndrome, but occasionally even vaccinated goats may develop acute enteritis. Affected goats develop severe diarrhea and profound depression; milk yield drops abruptly. Death may result in 24 hr. Treatment involves fluid therapy, correction of acidosis, and antibiotics.
Vaccination for contagious ecthyma (soremouth, see Contagious Ecthyma) is not indicated unless the disease exists in the herd. The main problems with infected kids are difficulty in nursing, spreading lesions to the does' udders or the assistants' hands, and attendance at goat shows being disallowed. Live virus vaccine is used by scarifying the skin (eg, inside the thighs or under the tail) and painting on the vaccine. Both natural lesions and those resulting from vaccination may last as long as 4 wk, but after the scabs have dropped off, the goats can go to shows.
Culling is vital to the overall productivity of the herd. Wasting disease is seen quite frequently; it is not a single disease, but a syndrome. Generally, if a goat is well fed, kept in a stress-free environment, and has good teeth and a low parasite load, it should thrive and produce. If it does not, and begins “wasting,” it should be culled immediately. The major causes of wasting disease, in addition to poor nutrition, parasitism, and dental problems, are paratuberculosis, internal visceral abscesses due to Corynebacterium pseudotuberculosis (ovis) or , locomotor problems (particularly arthritis due to retrovirus infection [CAE virus]), and any chronic hidden infections (eg, metritis, peritonitis, or pneumonia). Tumors are rarely seen. These diseases are rarely treatable, and many are contagious; this is the basis for the strict culling policy.
Paratuberculosis in goats differs from that in cattle (see Paratuberculosis) in that there is no profuse diarrhea, and gross postmortem lesions are less pronounced. Consequently, many cases may go undiagnosed at necropsy. The ileocecal node is the most rewarding tissue for bacteriologic culture and histopathology. Agar gel immunodiffusion is a useful serologic test, but it can be used only on a herd basis for test and cull. Availability is limited, and it will not function as a prepurchase screening test. Use of ELISA for diagnosis of caprine paratuberculosis is increasing. The control program for paratuberculosis in goats is similar to that in cattle.
Caprine arthritis and encephalitis (CAE, see Caprine Arthritis and Encephalitis) virus has emerged as an important infectious agent of intensively raised dairy goats. The prevalence of the infection in nondairy goats is comparatively low. CAE infection in goats can manifest in numerous ways: subclinical, persistent infection; a progressive paresis of young goats 2–12 mo old; agalactia with a firm, noninflamed udder at parturition in bred females; or an arthritic condition with pain and swollen joints in adults. A chronic, progressive interstitial pneumonia or a wasting syndrome may also be seen in adults. CAE infection has been considered primarily to be spread from dam to offspring through virus-laden colostrum and milk, and control programs have been aimed at feeding of heat-treated colostrum and pasteurized milk. However, even in herds in which this is practiced, infection may persist. Horizontal transmission between adults is also important in the spread of the disease. Regular testing and rigorous culling of all seropositive goats, or strict segregation of seropositive and seronegative goats, must be practiced if disease eradication is the goal.
For mastitis in goats, see Mastitis in Goats.
Last full review/revision July 2011 by David M. Sherman, DVM, MS, DACVIM