Investigation of abortions in brucellosis tested herds |
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| Authors: | PJ O'Hara Kathryn H Christiansen |
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| Institution: | 1. Animal Health Reference Laboratory , Wallaceville Animal Research Centre , Private Bag, Upper Hutt, New Zealand;2. Ministry of Agriculture and Fisheries , P.O. Box 2298, Wellington, New Zealand |
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| Abstract: | The mandatory reporting and investigation of bovine abortions provides a system for the surveillance of the progress of the Brucellosis Eradication Scheme and a warning of resurgence of brucellosis in tested herds. Before the scheme was introduced in 1971, about a quarter of all abortions were caused by Brucella abortus. By 1976, the percentage of abortions due to Brucella in herds under test for brucellosis had been reduced to 3.4%. Most Brucella abortions occurred during the seventh and eighth months of gestation. Cows in the 4- to 6-year-old age group were at greater risk of aborting from Brucella infection than heifers. Approximately 94% of all aborting cows were in herds which experienced three or fewer abortions. Less than 4% of herds experienced four or more abortions annually. In most cases of abortion due to brucellosis, more than one diagnostic test yielded positive results. However, 13.3% of cases were recognised by positive bacteriological results alone. |
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| Keywords: | Calves Vitamin B12 serum liver long-acting injection |
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