EFECTO DE LA INFECCIÓN CON LOS VIRUS DE RINOTRAQUEITIS INFECCIOSA BOVINA Y DIARREA VIRAL BOVINA SOBRE LA REPRODUCCIÓN EN BOVINOS NO VACUNADOS Effect of Infectious Bovine Rhinotracheitis Virus and Bovine Viral Diarrhea Virus Infections on Reproduction in a Non-Vaccinated Cattle Herd

A study was carried out to determine if infectious bovine rhinotracheitis virus (IBRV) and bovine viral diarrhea virus (BVDV) infections were involved in the reproductive efficiency of a non-vaccinated crossbred Brahman herd. Management of reproduction consisted of a four months breeding season (BS) with artificial insemination (AI) at first, and natural breeding. Eighty female cattle were categorized into two groups for comparison: 1) Deficient performance (DP) and 2) Good performance (GP), composed of 35 and 45 animals, respectively. A serological profile for both viruses was determined by ELISA (SVANOVA Biotech) on all cattle before and during the BS. Fifty one percent of both groups were infected with IBRV before the BS. Twenty six and 16% of the groups DP and GP, respectively, were infected with this virus during the BS, and 78 and 100% of them became pregnant and delivered normally. Association between IBRV infection and pregnancy was not found by Fisher test (P 0.62). Regarding BVDV, 86 and 78% of the groups DP and GP, respectively, were infected before BS and scarcely 3 and 7% of them were infected during the BS. Association between BVDV infection and pregnancy was not found (P 0.60). These results indicate that IBRV and BVDV infections were not involved in the reproductive efficiency of the herd.