Comparison of Feedlot Health, Nutritional Performance, Carcass Characteristics and Economic Value of Unweaned Beef Calves with an Unknown Health History and Weaned Beef Calves Receiving Various Herd-of-origin Health Protocols

Abstract

This study was conducted in a commercial feedlot to compare the health, nutritional performance, carcass characteristics and economic value of three groups of 600 lb (273 kg) beef steer calves-one group of unweaned calves of unknown health history and two groups of calves administered a herd-of-origin health protocol with at least a 45-day weaning period. Calves were purchased between December 1 and December 20, 2003, and were harvested between April 22 and June 2, 2004. Calves identified as persistently infected with bovine viral diarrhea virus remained in their respective treatment groups for the duration of the study. Mortality rates were low in all groups of steers and were unaffected (P>0.14) by treatment. Compared with steers administered health protocols, steers of unknown health history had higher L. (P<0.05) morbidity, lower average daily gain and lower feed intake, particularly early in the feeding period. Additionally, steers with an unknown health history were more likely than health protocol steers to receive multiple treatments for respiratory disease during the entire feeding period. Treatment costs were approximately $7 per head higher for steers of unknown health history. Although feed efficiency was not affected (P>0.57) by treatment, steers of unknown health history required an additional 16 days-on-feed to reach the desired back fat thickness. Neither quality grade nor yield grade was affected by treatment, but the trend was towards a lower (less favorable) quality grade and lower (more favorable) yield grade in calves of unknown health history. Unadjusted for days-on-feed, profit per head was not affected (P=0.64) by treatment; however, on the basis of an equal number of days-on-feed, steers administered the WeanVAC® health protocol at the herd of origin returned $33.71 more net income per head than steers of unknown health history, whereas steers administered other 45-day programs returned $11.36 more net income per head than steers of unknown health history.