A Comparison of three vaccine programs on the health, growth performance, and carcass characteristics of high-risk feedlot heifers procured from auction-markets
Keywords:bovine respiratory disease, BRD, endotoxin, feedlot, vaccination
A total of 2,575 beef heifers (BW = 568 ± 28.1 lb; 258 ± 12.7 kg) at high-risk of developing bovine respiratory disease (BRD) were enrolled in a randomized complete-block design study at a commercial feedlot to evaluate the effect of 3 vaccine programs on health, growth performance, and carcass characteristics. Dates of arrival to the feedyard served as the blocking factor and 10, 3-pen blocks were enrolled in the study (n = 10 replications per vaccine program). Chute- order randomization was used during arrival processing to assign heifers to 1 of 3 vaccine programs that differed by vaccine products or timing of the pentavalent modified-live viral vaccination: 1) Pyramid® 5 and Presponse® SQ during arrival processing (PRE), 2) Titanium® 5 and Nuplura® PH during arrival processing (TNA), and 3) Nuplura® PH during arrival processing with Titanium® 5 delayed until 28 days- on-feed (TND). No booster vaccinations were administered. Overall mortality, BRD morbidity, and BRD treatment success risks did not differ among the vaccine programs (P>0.13). There were numerically fewer mortalities attributable to acute interstitial pneumonia in TNA heifers than the TND and PRE heifers (probability of difference = 0.99 and 1.00, respectively). Mortality attributable to BRD did not differ between vaccine programs (probability of difference < 0.48). Endotoxin concentrations were measured in the Mannheimia haemolytica vaccines, and were lower in Nuplura® PH than Presponse® SQ. An arrival vaccine program implementing Titanium® 5 and Nuplura® PH had similar efficacy on BRD- related health outcomes as vaccinating with Pyramid® 5 and Presponse® SQ. Delaying a pentavalent viral vaccine until 28 days-on-feed did not affect health or growth-performance outcomes in this study.