Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 6/21/2002
Publication Date: 7/21/2002
Citation: Chirase, N., Purdy, C.W., Loan, R.W., Briggs, R., Duff, G., Avampato, J. 2002. Effect of environmental stressors and prophylactic antibiotic on performance, fever status and incidence of bovine respiratory disease of feeder steers [abstract]. Joint Abstracts of the American Dairy Science and Society of Animal Science.American Dairy Science Association 2002 Joint Meeting, July 21-25, 2002, Quebec City, Canada. 6:344.
Technical Abstract: Feeder cattle often encounter many environmental stressors and pathogens associated with the marketing process and translocation to the feedyard. Exposure to stressors could compromise the antioxidant and immune defense systems, resulting in morbidity and mortality in these calves. An experiment was conducted to determine the effects of prophylactic antibiotic treatment and posttransit commingling of feeder calves obtained from two sources (New Mexico and Tennessee), to determine performance and rate of bovine respiratory disease (BRD). One hundred twenty one (121) crossbred feeder steers (average BW 190 kg) were purchased in TN and eighty four (84) crossbred steers of similar size were obtained in NM and calves were vaccinated, weighed, rectal temperature (RT) measured, and randomly allotted into 3 commingling treatment groups (3 replicates per group): 1) New Mexico (NM), 2) Tennessee (TN) and 3) Commingled (Mixed). One-half of the steers in each treatment group received pretransit prophylactic Nuflor (1 mL/15 kg of BW, s.c.). Upon arrival at the Clayton Livestock Research Center, Clayton, NM, all steers were housed by groups and managed similar to commercial feedyard management protocols. Steers were also scored daily for BRD, weighed and rectal temperatures measured upon arrival (d 0), 7, 14, 21 and 28 d posttransit. The data were subjected to the analysis of variance using the General Linear Models procedure of SAS. There was no antibiotic treatment by commingling interaction (P >0.05) for ADG, RT or BRD rates. Bovine respiratory disease rate was higher in the TN and Mixed groups than the NM group (2.22 and 1.72 vs 0.92, respectively). However, on d 7, 14, 21 and 28 of the study, the NM calves gained less (P<0.01) and also had higher RT on d 28 than the TN and Mixed calves. Prophylactic antibiotic had no effect (P >0.05) on RT or ADG of calves of all treatment groups but lowered (P<0.05) BRD rates (1.33 vs 1.91). As the BRD rates or episodes of sickness increased, the ADG of calves decreased. These results suggest that more studies are required to understand the role of environmental stressors on feeder cattle performance and health.