Milk production and reproductive performance in dairy cows given bovine respiratory syncytial virus vaccine prior to parturition

Abstract

Objective To assess the effect of vaccination against bovine respiratory syncytial virus on milk production, reproductive performance, and health in lactating dairy cows. Design Prospective randomized block design. Animals 385 Holstein dairy cows and heifers. Procedure Cows were grouped by lactation number, season of calving, and previous mature equivalent 305-day milk production (where appropriate). Prior to parturition, cows and heifers were randomly assigned to be vaccinated 1M against infectious bovine rhinotracheltis, bovine viral diarrhea, and parainfluenza 3 viruses by use of a three-way vaccine, or to be vaccinated against those viruses as well as bovine respiratory syncytial virus, using a four-way vaccine. Milk production was measured daily through 305 days of lactation. Reproductive and medical records were reviewed to obtain insemination dates and record medical problems of cows in each vaccine treatment group. Results Compared with the three-way vaccine, administration of the four-way vaccine was associated with higher milk production (1.39 kg [3.06 Ib] more milk/d) in first-parity cows during the first 21 weeks of lactation. Vaccination did not have any effect on milk production after the first 21 weeks of lactation in cows of any parity. Conception rates at first insemination were higher for four-way vaccinated first-parity cows than for three-way vaccinated first-parity cows (54.6 vs 32.7%). Compared with second-parity cows that received the three-way vaccine, first insemination conception rate was improved for second-parity cows vaccinated with the four-way vaccine (28.9 vs 47.8%, respectively). In cows of third or greater parity, first insemination conception rate was not different between the 2 vaccine treatment groups. Clinical Implications Vaccination of heifers against bovine respiratory syncytial virus prior to partrition may increase milk production and first insemination conception rates. (J Am Vet Med Assoc 1997;210:1779–1783)