Diseases and mortality of adult goats in a South African milk goat herd

Saanen and South African Indigenous goats were crossbred, and all three types were compared in terms of productivity, milk production and diseases between 1988 and 1994. Clinical mastitis occurred in the herd at a moderate level (28 cases of clinical mastitis, including peracute outbreaks, in 251 lactations in six years). Peracute cases resulted in deaths, or loss of an udder half. The main organism identified was Staphylococcus epidermidis, infecting 109 of the 1032 udder halves sampled (10.6%). The other bacterial isolations were only 27 of 1032 udder half samples (2.6%), primarily of Staphylococcus aureus (23 of 27 colonies: 85%). Mannheimia haemolytica (formerly Pasteurella) and Streptococcus sp. were each identified once, and Escherichia coli twice. Somatic Cell Counts (SCC) were an unreliable indication of subclinical mastitis. Abscesses were not a major problem (up to 10 cases a year). Dystocia and the resultant metritis, occurred in only I I cases in a six year period. Squamous cell carcinoma developed on the udders of half of the 24 pure Saanens from the fourth lactation onwards, and they were culled. No cases were reported in the Crossbred goats. Alterations to the goat pens which provided adequate shade resolved the problem. Foot problems occurred when hooves had not been trimmed regularly. Serious eye infections seldom occurred. Six cases of adult goats with pneumonia were recorded. On two occasions samples were collected from goats that had swollen joints, but tests for caprine arthritis encephalitis (CAEV) were negative; this disease appears not to exist in South Africa. Internal parasites were not a significant problem in adult goats. Lice were the only external parasites in the penned goats. Indigenous goats appeared to be relatively resistant to tick infestation. Mortality increased with age, and as the size of the herd increased. The annual mortality rates of 10% for Saanens and 15% for Crossbreds were high, compared to that for the Indigenous goats of 4%. The most important causes of death were mastitis, ketosis and pneumonia. Pneumonia was diagnosed as the cause of death for five adult goats. Few cases of dystocia were recorded, but some goats were lost as a result of uterine infections and peritonitis. Pregnancy toxaemia occurred with increased demand for energy late in gestation. Plastic bags in the rumen caused deaths of some Indigenous goats in the veld paddocks in later years. Only two cases of heartwater were recorded.