|Vander ley, Brian|
Submitted to: Proceeding of Plains Nutrition Council Symposium
Publication Type: Abstract only
Publication Acceptance Date: 4/4/2010
Publication Date: 4/22/2010
Citation: Richeson, J.T., Kegley, E.B., Vander Ley, B.L., Ridpath, J.F. 2010. Pre-Arrival Management of Newly Received Beef Calves With or Without Exposure to a Persistently Infected Bovine Viral Diarrhea Virus Type I Calf Affects Health, Performance, BVDV Type I Titers, and Circulating Leukocytes [abstract]. Plains Nutrition Conference. p. 117. Interpretive Summary:
Technical Abstract: Bovine viral diarrhea virus (BVDV) is a major culprit in the development of BRD either directly via acute clinical disease or through indirect effects of immunosuppression. Calves born persistently infected (PI) with BVDV are the primary vector for introduction of the virus into herds or production groups. While the prevalence of PI-BVDV calves in the feedlot is thought to be low, a single PI-BVDV animal has the potential to expose an entire pen and adjoining pens to the virus. The purpose of this project was to see if the consequences of exposure to a PI-BVDV calf in single source, preconditioned (PC) cattle differed from the consequences of exposure in commingled, auction market (AM) cattle. Our approach was to compare treatments of PC or AM origin, with (PI) or without (CON) exposure to a PI-BVDV calf in a 2 x 2 factorial arrangement to evaluate effects on health and performance in a randomized block design using the MIXED procedure of SAS. Four sets (block) of PC steers (n = 236) from 3 ranches were selected randomly, weaned, dewormed, vaccinated, tested for PI-BVDV status, and kept on the ranch for greater than or equal to 42 d. Subsequently, PC calves were transported to a stocker unit (SU), weighed (251 ± 2 kg), bled, and randomly assigned to treatment (PCPI or PCCON) with no additional processing. Simultaneously, 4 sets of AM calves (n = 292) were assembled from regional auction markets for delivery to the SU within 24 h of PC arrival. The AM calves were weighed (245 ± 1.3 kg) and administered the same processing procedures as PC; however, bull calves were castrated, stratified by sex, and AM calves were randomly assigned to treatment (AMPI or AMCON). Calves were fed identically and followed the same antibiotic treatment protocol. Daily gain for the entire 42 d was greater (P < 0.001) for PC (1.2 kg) than AM (0.85 kg). There was an exposure effect (P = 0.002) on ADG from d 28 to 42; CON gained 1.12 kg vs. 0.90 kg for PI. Morbidity rate was greater (P < 0.001) in AM (70%) than PC (7%). Treatment with a third antibiotic occurred more often (P = 0.04) for PI, likewise the greatest number of chronic cattle were AMPI (P = 0.06). BVDV type I titer levels were greater on d 0 for PC (treatment x day, P < 0.001), and seroconversion to BVDV type I on d 0 was 100% for PC vs. 23% in AM. Neutrophil:lymphocyte was greater (P < 0.001) for AM on d 14 and 28. Results suggest that PC gain faster and require fewer antibiotic treatments; whereas, PI-BVDV exposure reduced gain from d 28 to 42 and increased antibiotic treatment cost in AM.