       Document 0729
 DOCN  M9640729
 TI    A serological survey of bovine syncytial virus in Ontario: associations
       with bovine leukemia and immunodeficiency-like viruses, production
       records, and management practices.
 DT    9604
 AU    Jacobs RM; Pollari FL; McNab WB; Jefferson B; Department of Pathology,
       University of Guelph, Ontario.
 SO    Can J Vet Res. 1995 Oct;59(4):271-8. Unique Identifier : AIDSLINE
       MED/96127198
 AB    Of the 920 cows tested, 56.7% showed antiretroviral serological
       reactivity. Prevalence rates (95% confidence interval) of antiretroviral
       antibodies among individual dairy cows in Ontario were: BIV 5.5%
       (4.0-7.0), BLV 25.7% (22.9-28.6), and BSV 39.6% (36.4-42.8). The
       following percentages of cows showed serological reactivity against the
       specified retroviruses: BIV 2.3%, BLV 14.0%, BSV 27.5%, BIV and BSV
       1.3%, BIV and BLV 0.9%, BLV and BSV 9.9%, BIV and BLV and BSV 0.9%.
       These rates of sero-positivity are similar to those found in other
       countries. Serological test results were not adjusted for sensitivity
       and specificity. The prevalence rates of antibodies to the three
       retroviruses (BIV, BLV, and BSV) were significantly different, but no
       associations were observed between specific retroviral serological test
       results among individual cows. The prevalence rates of BIV and BSV
       seropositivity were constant across Ontario, whereas, there was a
       significant trend for the prevalence rate of BLV seropositivity to
       decrease going from southwestern to eastern Ontario; cows in eastern
       Ontario had approximately half the prevalence rate of those in
       southwestern Ontario. Cows that were seropositive for BSV were
       significantly older than BSV seronegative cows. There was no association
       between culling rate and BSV serology. Significant negative associations
       were found with winter or summer housing of calves separate from adults
       and summer outdoor exercise for dry cows. The use of calf hutches in the
       summer had a significant positive association with BSV seropositivity.
       Regression analyses were done to assess the association of retroviral
       (BIV, BLV, and BSV) seropositivity on calving interval, milk somatic
       cell count, and milk production. Serological test results for BIV, BLV,
       and BSV were entered into all models and all models were adjusted for
       intra-cluster (intraherd) correlation. Herd size and age were found to
       be important confounding variables. BIV seropositivity was not
       associated with any changes in production using this approach, however
       when considered in isolation BIV seropositivity remained associated with
       decreased milk production. BLV seropositivity was significantly
       associated with longer calving intervals and higher somatic cell counts
       in older cows. As well, in older cows, BSV seropositivity was
       significantly associated with higher milk production.
 DE    Age Factors  Animal  Antibodies, Viral/*BLOOD  Birth Intervals  Cattle
       Cattle Diseases/*EPIDEMIOLOGY/IMMUNOLOGY/VIROLOGY  Female  Housing,
       Animal  Immunodeficiency Virus, Bovine/*IMMUNOLOGY  Leukemia Virus,
       Bovine/*IMMUNOLOGY  Milk/METABOLISM  Ontario/EPIDEMIOLOGY  Prevalence
       Retroviridae Infections/EPIDEMIOLOGY/IMMUNOLOGY/*VETERINARY/  VIROLOGY
       Spumavirus/*IMMUNOLOGY  Support, Non-U.S. Gov't  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

