Effect of weaning status and implant regimen on growth, performance, and carcass characteristics of steers

J. P. Schoonmaker, F. L. Fluharty, S. C. Loerch, T. B. Turner, S. J. Moeller, D. M. Wulf

Research output: Contribution to journalArticle

Abstract

One hundred forty-three Angus x Simmental crossbred steers (initial BW = 155.1 ± 4.5 kg) were used in a 2-yr study (yr 1, n = 67; yr 2, n = 76) to determine the effects of weaning age, implant regimen, and the weaning age x implant regimen interaction on steer growth and performance, organ mass, carcass characteristics, and cooked beef palatability. Steers were early-weaned at an average age of 108 d (EW) or normally weaned at an average age of 202 d (NW) and allotted by weight to an aggressive or nonaggressive implant regimen. On their respective weaning dates, EW and NW steers were penned individually and fed a grain-based diet until they were slaughtered at a final BW of 546 kg. A subsample of steers (n = 2 per treatment) were slaughtered at 254 kg. At 254 kg, EW steers implanted with the aggressive implant regimen had 64% greater backfat depth than those implanted with the nonaggressive implant regimen; conversely, NW steers implanted with the aggressive implant regimen had 52% lower backfat depth than those implanted with the nonaggressive implant regimen (weaning status x implant regimen interaction; P < 0.01). A similar interaction was observed for empty visceral organ weights. Early-weaned steers were younger (354.7 vs 372.4 d; P < 0.01) at final slaughter but were in the feedlot longer (246.5 vs 169.6 d; P < 0.01) than NW steers, whereas the aggressive implant regimen decreased days fed (203.3 vs 212.7; P < 0.07) compared to the nonaggressive implant regimen. Overall ADG was greater for EW than for NW steers (1.61 vs 1.50 kg/d; P < 0.01) and for the aggressive compared with the nonaggressive implant regimen (1.59 vs 1.52 kg/d; P < 0.02). Early-weaned steers consumed less DM per day (7.4 vs 8.5 kg/d; P < 0.01) and were more efficient (0.217 vs 0.208 kg/kg; P < 0.02) but consumed more total DM (1,817 vs 1,429 kg; P < 0.01) than NW steers while in the feedlot. Implant regimen did not affect DMI (P > 0.37) or feed efficiency (P > 0.15). Weaning status did not affect carcass characteristics (P > 0.14), final empty body composition (P > 0.25), or final longissimus muscle composition (P > 0.18); however, steaks from EW steers had higher (P < 0.05) taste panel tenderness and juiciness ratings than steaks from NW steers. The aggressive implant regimen decreased yield grade (P < 0.02), but did not affect quality grade (P > 0.86) compared to the nonaggressive implant regimen. Placing early-weaned steers on an aggressive implant regimen is a viable management option.

Original languageEnglish (US)
Pages (from-to)1074-1084
Number of pages11
JournalJournal of animal science
Volume79
Issue number5
DOIs
StatePublished - May 2001

Keywords

  • Beef Cattle
  • Growth Promoters
  • Weaning

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology
  • Genetics

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    Schoonmaker, J. P., Fluharty, F. L., Loerch, S. C., Turner, T. B., Moeller, S. J., & Wulf, D. M. (2001). Effect of weaning status and implant regimen on growth, performance, and carcass characteristics of steers. Journal of animal science, 79(5), 1074-1084. https://doi.org/10.2527/2001.7951074x