Animal Science, Department of


Date of this Version

January 1996


Published in 1996 Nebraska Beef Cattle Report; published by Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln.


The use of growth promoting implants with finishing cattle is common feedlot practice to increase weight gain. However, the payout of hormone from the implants decreases with time. As the concentration of hormone(s) in the blood decreases, it is not completely clear how the growth response of the cattle is affected. Trenbolone acetate (TBA, a synthetic product of the male hormone testosterone) combined with estrogen may increase mature body size by increasing lean tissue growth. However. there is limited information available to determine if TBA/estrogen continues to stimulate weight gain throughout a four-month feeding period. Therefore. the objective of this research was to evaluate the influence of TBA/estrogen implants during the final 30 days of the finishing period on performance. carcass characteristics. and the economics of finishing yearling steers.