Comparison of a multivalent viral vaccine program versus a univalent viral vaccine program on animal health, feedlot performance, and carcass characteristics of feedlot calves.

A field study was conducted under commercial feedlot conditions at 2 sites in western Canada to determine the relative effects of a univalent viral vaccine (MLV 1) program versus a multivalent viral vaccine (MLV 4) program on animal health; feedlot performance; and carcass characteristic variables of fall-placed, auction market derived, feedlot calves. Five thousand one hundred and sixty-three calves were processed and randomly allocated to 1 of 2 experimental groups as follows: MLV 1, which received a modified live infectious bovine rhinotracheitis (IBR) virus vaccine upon arrival at the feedlot and again at approximately 70 days on feed (DOF); or MLV 4, which received a modified live IBR virus, parainfluenza-3 virus, bovine viral diarrhea virus, and bovine respiratory syncytial virus vaccine upon arrival at the feedlot and again at approximately 70 DOF. A total of 20 pens (10 pens at the site located near High River, Alberta and 10 pens at the site located near Vegreville, Alberta) were allocated to the study. On both a live and carcass weight basis, final weight, weight gain, and average daily gain (ADG) were significantly (P < 0.05) improved in the MLV 4 group as compared with the MLV 1 group. However, there were no significant (P > or = 0.05) differences in DOF, daily dry matter intake, dry matter intake to gain ratio (DM:G) live, or DM:G carcass between the experimental groups. In addition, there were no significant (P > or = 0.05) differences between the experimental groups in any of the carcass characteristic variables measured. The initial undifferentiated fever (UF) treatment rate was significantly (P < 0.05) lower in the MLV 4 group as compared with the MLV 1 group. There were no significant (P > or = 0.05) differences in the other measures of health between the experimental groups. In the economic analysis, there was a net advantage of $0.74 CDN per animal in the MLV 4 group as compared with the MLV 1 group due to lower initial UF treatment and improved ADG, even though the cost of the vaccine program was higher in the MLV 4 group.