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Title: RISK FACTORS FOR SEROPREVALENCE OF OVINE LENTIVIRUS IN BREEDING EWE FLOCKS IN NEBRASKA, USA

Author
item Keen, James
item HUNGERFORD, LAURA - UNIVERSITY OF ILLINOIS
item WITTUM, THOMAS - OHIO STATE UNIVERSITY
item Kwang, Hwei Sing
item LITTLEDIKE, E - OMAHA COL HLTH CAREERS

Submitted to: Preventive Veterinary Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/26/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Ovine lentivirus (OLV) is a slow onset viral infection of sheep that infects many U.S. flocks and can have significant negative affects on sheep production. The prevalence of the risk factors for OLV infection in 1466 breeding ewes in nine flocks at the U.S. Meat Animal Research Center was determined using a new enzyme immunoassay to detect infected sheep. Intensive confinement birth and rearing, older weaning ages, and older ewe ages were associated with higher rates of OLV infection in ewes. Prevalence also varied by flock, with Finnsheep and Texel ewe flocks having the highest prevalence and Booroola Merino and Suffolk ewe flocks having the lowest OLV prevalence. These findings support the hypothesis that management efforts to control OLV infection should concentrate on events early in the life of sheep, since this period is associated with factors that can effect the risk of OLV infection.

Technical Abstract: The prevalence of and risk factors for ovine lentivirus (OLV) infection in 1466 breeding ewes in nine U.S. Meat Animal Research Center (MARC) flocks was determined using a recombinant transmembrane protein ELISA to detect serum anti-OLV antibodies and define infection. Based on multiple logistic regression modeling, confinement birth and rearing [odds ratio (OR) = 1.6], older weaning ages (OR = 1.1/week), and older age (OR = 1.3 to 2.5/year beyond age 1) were significantly associated with higher OLV prevalence in ewes. Prevalence also varied significantly by flock, with Finnsheep and Texel ewes having the highest prevalence and Booroola Merino and Suffolk ewes having the lowest prevalence. These findings support the hypothesis that management control efforts should concentrate on events early in the life of sheep, since this period is associated with factors which can modulate the risk of OLV infection.