THE INFLUENCE OF SUPPLEMENTAL CHROMIUM AND VACCINES ON THE ACUTE-PHASE RESPONSE OF NEWLY ARRIVED FEEDER CALVES

The acute phase response as indicated by serum haptoglobin and total h aemolytic complement activity (CH50) was measured in 72 crossbred stee r calves purchased at sales in Ontario. During the 28 day (d) trial, 1 8 steers were randomly assigned to each of the following groups: 1) co ntrol; 2) vaccinated (Infectious Bovine Rhinotracheitis, Parainfluenza -3, Bovine Viral Diarrhea, Bovine Respiratory Synctial Virus vaccine p lus Pasteurella haemolytica vaccine); 3) supplemental chelated Cr (0.1 4 mg/kg); and 4) Cr plus vaccines. Haptoglobin concentrations were low at arrival, increased (P < 0.05) on day 7, and returned to near initi al levels (P > 0.05) by day 14. Supplemental Cr reduced (P < 0.05) hap toglobin on day 7 when morbidity was highest. Following antibiotic tre atment for respiratory disease haptoglobin was lower (P < 0.05) than d uring morbidity; however, during morbidity, haptoglobin concentrations were not greater in sick calves (P > 0.05) than in healthy calves. Co mplement activity was lowest on day 7 (P < 0.05) and peaked on day 14 (P < 0.05). Complement activity tended to be lower on day 7 for vaccin e, Cr, and Cr+ vaccine groups; however, the difference from controls w as not significant (P > 0.10). Complement activity did not increase on day 14 (P > 0.05) with Cr supplementation as in other treatments. Mor bid calves had lower (P < 0.05) CH50 activity than healthy calves on d ay 14. Following antibiotic treatment, the Cr-supplemented group had h igher (P < 0.05) CH50 than during morbidity. In general, chromium supp lementation reduced the acute phase response in newly arrived feeder c alves.