Table 2 illustrates that there was no significant differences between treatments as measured by first service conception rate, overall pregnancy rate or calving rate. The bulk of the information suggests that if implants are going to be used on heifer calves that might be kept for replacements, they should be implanted only once between six weeks of age and weaning. Ralgro is the only implant with a label for use in calves under 45 days of age. For operations in a terminal program, keeping no replacement heifers, implanting each calf at birth with Ralgro and then again later during the suckling period with Ralgro or another product would tend to make economic sense. If keeping heifer calves for replacements, Ralgro should not be used in heifers under six weeks of age.
Hormones are present in almost all foods whether of animal or plant origin.
Hormones are naturally occurring chemicals that are essential to life. The increase in the level of estrogen in beef from an implanted steer is biologically insignificant. Groups such as the World Health Organization and the United Nations Food and Agricultural Organization have concluded that the proper use of growth promotant implants is safe. The proper use of implants is an important method in which the overall efficiency of the beef industry can be improved.