Agricultural Research Division of IANR


Date of this Version



The Professional Animal Scientist 25 ( 2009 ):145–149


Copyright 2009 American Registry of Professional Animal Scientists


Two experiments were conducted to determine the effect of delaying initial feedlot implant on BW, ADG, and carcass characteristics. At receiving, steers were assigned to 1 of 2 treatments: 1) implant at feedlot entry (NORM) or 2) implant 30 d after feedlot entry (DELAY). In Exp. 1, steers (n = 200) were not implanted until feedlot entry; however, in Exp. 2 steers (n = 209) were implanted at approximately 50 d of age. In Exp. 1, there was a tendency (P = 0.11) for BW at d 30 to be heavier (10 kg) for NORM compared with DELAY; however, all other BW measures were similar (P = 0.29). In Exp. 2, BW measures were also similar (P = 0.82) for NORM and DELAY. In both experiments, carcass weight, fat thickness, LM area, and YG were similar (P = 0.51). Additionally, in both experiments marbling scores (P = 0.58) and the percentage of carcasses grading USDA Choice and greater were similar (P = 0.54) when comparing NORM and DELAY. In these studies, delaying initial feedlot implant had no effect on BW, ADG, or carcass measures including YG and QG.

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