1. Effects of long- or short-term exposure to a calf identified as persistently infected with bovine viral diarrhea virus on feedlot performance of freshly weaned, transport-stressed beef heifers
- Author
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Elam, N.A., Thomson, D.U., and Gleghorn, J.F.
- Subjects
Viral diarrhea -- Physiological aspects ,Viral diarrhea -- Prevention ,Disease transmission -- Evaluation ,Vaccination of animals -- Evaluation ,Livestock industry -- Research ,Heifers -- Physiological aspects ,Heifers -- Health aspects ,Zoology and wildlife conservation - Abstract
A single experiment with a completely randomized design was conducted to evaluate the effects of long- or short-term exposure to a calf identified as persistently infected with bovine viral diarrhea virus (PI-BVD) on feedlot performance and carcass characteristics of freshly weaned, transport-stressed beef heifers. Two hundred eighty-eight heifers that had been vaccinated for BVD before weaning and transport were processed and given a metaphylactic antibiotic treatment at arrival and were fed common receiving, growing, and finishing diets for a 215-d period. Treatments were designed to directly or adjacently expose the cattle to a PI-BVD heifer. Directly exposed treatments were 1) negative control with no PI-BVD calf exposure (control), 2) PI-BVD calf commingled in the pen for 60 h and then removed (short-term exposure), and 3) PI-BVD calf commingled in the pen for the duration of the study (long-term exposure); and spatially exposed treatments were 1) negative control with no PI-BVD calf exposure (adjacent pen control), 2) PI-BVD calf commingled in the adjacent pen for 60 h and then removed (adjacent pen short-term exposure), and 3) PI-BVD calf commingled in the adjacent pen for the duration of the study (adjacent pen long-term exposure). Exposure to a PI calf transiently (60 h) or for the duration of the feeding period (215 d) did not affect (P [greater than or equal to] 0.25) final BW compared with heifers that were not exposed. Neither period nor overall DMI was affected (P [greater than or equal to] 0.37) by PI-BVD calf exposure, and no differences (P [greater than or equal to] 0.44) were observed between short- and long-term exposed heifers in the direct or spatially exposed groups. Likewise, total trial ADG was not affected (P [greater than or equal to] 0.36) and overall efficiency of gain (P [greater than or equal to] 0.19) was unaffected by PI-BVD calf exposure in the direct or spatially exposed groups. The results from this study suggest that exposing previously vaccinated, freshly weaned, transport-stressed beef calves to a calf that is persistently infected with bovine viral diarrhea virus has little, if any, marked effects on health, performance, or carcass characteristics. Key words: beef cattle, bovine viral diarrhea virus, feedlot, persistent infection
- Published
- 2008