J. P. Schoonmaker,
F. L. Fluharty,
T. B. Turner,
S. J. Moeller,
S. C. Loerch 1
The Ohio State University Department of Animal Sciences
Sixty-seven Angus - Simmental crossbred steers (initial BW 341.3 ± 13.7 lbs) were used in a 2x2 factorial experiment to determine the effects of weaning age and implant regimen on growth and performance. Steers were either early-weaned at an average age of 113 d (EW) or normal-weaned at an average age of 204 d (NW), and allotted by weight to an aggressive (A) or non-aggressive (NA) implant regimen. EW-A and NW-A steers were implanted with Synovex-C at an average age of 163 d, and Revalor-S at an average age of 204 d, and 295 d if BW was < 1,050 lbs. EW-NA and NW-NA steers were implanted with Synovex-S at an average age of 204 d, and 295 d if BW was < 1,050 lbs. Steers were penned individually and fed an 85% concentrate, 12.4% CP finishing diet. Steers were slaughtered when they reached 1,205 lbs. Days on feed were greater (P < 0.01) for EW vs. NW (241 vs. 173 d, respectively) and tended to be lower (P < 0.12) for A vs. NA (201 vs. 213 d, respectively). Overall average daily gain (ADG) was higher (P < 0.0001) for EW vs. NW (3.64 vs. 3.26 lb./d, respectively), and for A vs. NA (3.55 vs. 3.35 lb./d, respectively; P < 0.03). Daily post-weaning DMI was lower for EW vs. NW, but total post-weaning DMI was higher (P < 0.0001) for EW vs. NW (3,965.0 vs. 3,210.3 lb., respectively). Gain/feed was improved (P < 0.06) for both EW vs. NW (0.219 vs. 0.209 lb./lb., respectively) and A vs. NA (0.219 vs. 0.209 lb./lb., respectively). Final age was lower (P < 0.01) for EW vs. NW (353 vs. 378 d, respectively). Percentage of steers not reaching 1,150 lbs was lower (P < 0.02) for A vs. NA (0.0 vs. 15.3%, respectively). Placing early-weaned calves on an aggressive implant regimen is a viable management option. Early-weaned steers convert feed more efficiently and gain faster from birth until slaughter than do NW steers.
1 For more information, contact at The Ohio State University, Ohio Agricultural Research and Development Center, 114 Gerlaugh Hall, 1680 Madison Avenue, Wooster, OH 44691; 330-263-3903, e-mail: loerch.1@osu.edu