Effect of testing and removal of feeder calves persistently infected with bovine viral diarrhea virus at the time of feedlot arrival and outcome on health, performance, and carcass characteristics

Abstract

Twelve lots of auction-derived steers totaling 1,577 head with an unknown health history (initial body weight 660 lb [300 kg]) were used to investigate testing and removal of feeder calves persistently infected with bovine viral diarrhea virus (PI-BVDV) upon arrival at a single feedlot in central Kansas. Pens with a PI-BVDV calf present at arrival were considered exposed and were compared to pens of steers that arrived without a PI-BVDV calf in the group. Both exposed and non-exposed pens of steers were followed from arrival through harvest to investigate the impact of exposure on health, performance, and carcass characteristics of feedlot cattle. A significant difference in the morbidity between exposed (2.3%) and non-exposed (7.2%) cattle was found (P<0.01). No differences in retreatment or mortality rates were found between groups. Exposure to a PI-BVDV animal for less than 48 hours after arrival did not have an effect on performance parameters. There was an increased percentage of USD A yield grade 4 and 5 (P=0.01) carcasses in the exposed cattle, but no other differences in carcass characteristics were found between groups.