Evolution of Enzootic Bovine Leukosis prevalence in an university dairy herd

Abstract

The prevalence of Enzootic Bovine Leukosis virus infection was determined in adult cows of the catholic university of Paraná (Pontifícia Universidade Católica do Paraná) dairy herd in 2000, 2003 and 2006 using the agar-gel immunodiffusion. The prevalence of the infection in adult lactating cows was respectively, over the years, 63.33%, 81.08% and 55.56%. Serum samples of all animals were taken in 2006, observing a continuously rise in antibody prevalence over the time up to more than 80% in animals older than 60 months, after vanishing of colostral maternal antibodies. The possible causes of this high prevalence were discussed under the particular circumstances of a teaching and research farm of an university.