EFFECT OF RE-17 MUTANT SALMONELLA-TYPHIMURIUM BACTERIN-TOXOID ON RESPIRATORY-DISEASE AND PRODUCTION

A total of 352 head of Holstein steers averaging 530 lbs in bodyweight were vaccinated upon arrival at a feedyard with Re-17 mutant Salmonel la typhimurium bacterin-toxoid and commingled with 351 head of control s averaging 538 lbs. The steers were uniformly intermingled in pens ho lding approximately 140 head each. The health maintenance costs; weigh ts at 30, 60, and 275 days; overall feed conversion; and weight gains were calculated, recorded for each group and pen, and statistically co mpared. There were significant (P < 0.05) differences between vaccinat ed and control groups in terms of bovine respiratory disease complex ( BRDC) health costs when medicine/hospitalization, treatment days, and second sick pulls were compared. There was not a significant differenc e in the number of total deaths, 15 controls, and 13 vaccinates, but t here was only one vaccinate death due to BRDC compared to five control s. The results of this study suggest that health maintenance costs in the vaccinated cattle were significantly lowered by vaccination with t he Re-17 mutant S. typhimurium bacterin-toxoid.