The use of anabolic implants in replacement heifers can be an area of large debate among cow-calf producers. The data revealed an average increase in weaning weights by 18.6 pounds and a 28 pound increase in yearling weight of implanted heifers compared to non-implanted females. In regards to age at puberty, the trial showed no significant difference in age among the implanted and non-implanted heifers. The implanted heifers had a 15 CM2 larger pelvic area. However, the increase in pelvic area had no effect on dystocia when compared to the non-implanted females.
Pregnancy rate has a major impact on the profitability of a cow-calf operation.
Unfortunately, the data from the trials indicated neither a positive or negative effect on pregnancy rates from implanting. Purvis et al. Group 2 received this treatment for 60 days prior to breeding and group 3 for 30 days prior to breeding. Results of the trial are listed in Table 5. Weight gains for each group were similar before ration changes.