Document Type Master's Dissertation Author Dungu-Kimbenga, Baptiste URN etd-01052007-100419 Document Title Study on the effects of a natural Maedi visna virus infection on sheep productivity Degree MSc (Veterinary Ethology) Department Veterinary Production and Ethology Supervisor
Advisor Name Title Prof G Bath Committee Chair Dr D W Verwoerd Committee Co-Chair Keywords
- lentivirus infections
- sheep virus diseases
- maedi-visna disease
Date 2000-04-21 Availability unrestricted AbstractA cohort study was conducted in order to measure the effect of the chronic indurative lymphocytic mastitis caused by the South African strain ofMaedi visna virus (SA-OMVV) on the pre-weaning growth of lambs born of naturally infected and uninfected ewes kept under similar conditions. 50 naturally infected ewes and 40 controls from an MVV-free source were purchased and kept separately. All ewes were of the same breed - the Dorper¬and 3 to 4 years old. From the adaptation period, through mating, pregnancy and lactation periods they were monitored for MVV antibodies and managed under similar conditions. The lambs were weighed at birth and thereafter every two weeks until the age of 90 days, when they were weaned. The ewes were slaughtered, their udders examined histologically and the lesions were assessed by counting typical lymphocytic follicles. Although the observed values indicated a correlation between the number of follicles in the udder and the reduction in the growth rate of the lambs, this was not statistically significant. Similarly, despite higher counts of lymphoid follicles in the udder of sero-positive ewes as compared to sero-negatives and the observed lower ewe productivity indexes (EPI) in infected ewes, no statistically significant differences were found in the EPI of ewes in different follicle categories.
The present study was a first attempt to evaluate the effect of the SA-OMVV infection on sheep productivity in South Africa.
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Please cite as follows:
Dungu-Kimbemga, B 2000, Study on the effects of a natural Maedi Visna virus infection on sheep productivity, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-01052007-100419/ >
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