Summary and Implications
Two hundred eighteen steers were finished in a total confinement deep-bedded system at the Armstrong Research Farm, Lewis, IA during 2009. All steers were implanted with Synovex-Choice on day 1 and half the steers in each pen were implanted with Synovex-Choice on day 56. All steers were harvested on day 118. The 2nd implant resulted in an immediate and significant improvement in average daily gain. In the 76 day weigh period following reimplantation the group receiving the 2nd implant gained .66 lb/day more than the group not receiving an additional implant. The overall average daily gain of steers implanted once compared to the steers implanted twice was 3.81 vs. 4.10. The 2nd implant group produced significantly heavier carcasses. There were no significant differences in carcass fat cover or ribeye area. The twice implanted steers had a lower percentage low Choice or better (P=.0571) and a greater percentage Select (P=.0555). Implanting a second time resulted in an increase in carcass weights, an almost significant reduction in % Choice but still resulted in a numerical, non-significant increase in carcass value.
Iowa State University
Busby, W. Darrell; Maxwell, Dallas L.; and Strohbehn, Daryl R.
"Effects of Second Implant on Feedlot Gain and Carcass Traits ,"
Animal Industry Report:
AS 656, ASL R2503.
Available at: http://lib.dr.iastate.edu/ans_air/vol656/iss1/24