The effects of maedi-visna virus infection on productivity in ewes

Abstract

Five sets of data from four separate sheep flocks (1445 ewes) were used to assess the effects of subclinical maedi-visna virus infection (as determined by serological procedures) on productivity in ewes. In general, infection with maedi-visna virus lowered productivity. Infection reduced conception rates, with the chances of an infected ewe conceiving being only approximately 0.67 times those of a non-infected ewe. For ewes which did conceive, there was no effect of infection on the number of lambs born. The birth weights of lambs born to middle-aged (3-4 years) infected ewes were 3-6% lower than the weights of lambs born to non-infected ewes of the same age. There was very little effect of infection in younger (1-2 years) and older (5+ years) ewes: some factors which may have biased these results are discussed. Lamb weights at 25-50 days of age were reduced by maedi-visna infection in the ewe but the results were not statistically significant..RE: 33 ref.; SC: ZA; CA; VE; 0V; 0ISource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=4&issue=5%2f6&spage=471&pages=471-484&date=1987&title=Preventive%20Veterinary%20Medicine&atitle=The%20effects%20of%20maedi-visna%20virus%20infection%20on%20productivity%20in%20ewes.&aulast=Dohoo&pid=%3Cauthor%3EDohoo%2c%20I%20R%3bHeaney%2c%20D%20P%3bStevenson%2c%20R%20G%3bSamagh%2c%20B%20S%3bRhodes%2c%20C%20S%3C%2Fauthor%3E%3CAN%3E19872200103%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3