Abstract
Crossbred male calves (225) with an average weight of 200 kg were used to investigate the metabolic response of feeder steers to the marketing and transportation (MT) processes and Infectious Bovine Rhinotracheitis virus (IBRV) infection. In trials 1 and 2, serum zinc (Zn), copper (Cu) and protein alterations occurring in calves naturally exposed to bacteria, viruses and stressors involved in bovine respiratory disease (BRD) were measured. Trial 3 and 4 were controlled studies with calves inoculated with IBRV, and acute phase response measured during the IBRV infection. Trial 4 calves were maintained in metabolism crates allowing daily urine and fecal collection and determination of nitrogen (N) balance. Mean serum Zn concentrations significantly decreased during BRD or IBRV infection, with lowest levels being when a calf first exhibited clinical morbidity. Serum Cu increased significantly as a result of either BRD or IBRV infection. Urinary Zn and Cu excretion increased significantly during IBRV infection in trial 4, indicating a greatly increased mobilization of metabolic copper. Serum protein patterns seen in all trials were similar with MT, BRD or IBRV stress causing an increase in total proteins, alpha and gamma globulins. Concomitant decreases in serum albumin and beta 2 globulins were observed. The degree of alteration in the serum protein pattern corresponded to the degree of morbidity observed. A significant increase in blood urea nitrogen, total bilirubin and a significant decrease in lactate dehydrogenase were observed as a result of IBRV infection. Nitrogen balance results indicated an increased excretion of urinary (17.9 vs 31.5 g/d) and fecal N (15.2 vs 24.2 g/d) resulting in a net loss of N during the fever of the IBRV infection in trial 4. Curve peeling analysis of %^15N excess/h (^15N) infusion data showed an increased catabolism (.218 vs .312 %^15N) and excretion of body N (.014 vs .026 %^15N), along with a decreased synthesis (.367 vs .189 %^15N) and half-life of ^15N (66.9 vs 48.3 h) as a result of the IBRV infection.
Orr, Carolyn Louise (1985). Acute phase response and body protein kinetics of bovine respiratory disease infected calves. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -596446.