One hundred and ninety-five crossbred steers were used to compare lifetime
implant strategies and study the effects of implanting during the suckling period on
performance in the growing and finishing periods. There were no differences in
growing period gains when both groups were implanted in the suckling period and
the growing period. However, steers implanted in the suckling period but not
implanted in the growing period had significantly lower gains than all other
treatments including controls. Steers implanted only in the growing period had
better feed efficiency in the growing period than both controls and steers
implanted only in the suckling period.
Steers reimplanted during the finishing period had similar finishing gains
regardless of prior implant treatment, and all implanted cattle gained faster than
controls in the finishing period. Steers not reimplanted during the finishing period
had lower gains than those reimplanted. Implanting in the finishing period resulted
in better feed efficiency.
All implanted cattle that were reimplanted in the finishing period had
higher lifetime gains than controls, but there was no difference between implant
combinations. The only carcass characteristic changed by implanting was quality
grade, which was reduced by all implant combinations with the exception of
implanting only in the finishing period.
Implanting during the suckling period did not reduce cattle performance
during the growing and finishing periods when the steers were also implanted
during these periods. This study emphasizes the importance of implanting twice in
the finishing period to maximize finishing gain and final weight.
