048 Effects of an intensified, semi-confinement cow/calf production system on feedlot performance of growing and finishing steers

Abstract

In the first year of a multiple-year experiment, feedlot performance and carcass traits were evaluated for 39 fall-born Angus, Angus × Hereford steers from two cow/calf production systems. Production systems were 1) intensive, semi-confined production system utilizing native range (spring and fall), dry-lot feeding with limited winter wheat pasture grazing (winter), and limited cover crop grazing (summer); 2) extensive, season-long continuous grazing on native range with protein supplementation during winter, representative of traditional cow/calf management in the region. Initial BW upon entering the feedlot was greater for steers produced in the intensive (IS) system than for steers in the extensive (ES) system (P < 0.05) at 370 and 334 kg hd^-1respectively. Analysis of Variance was conducted using the GLM procedure in SAS software. Back fat thickness was included as a covariate in analysis of performance and carcass traits. Steers produced in the IS had 18 % greater (P < 0.05) ADG and a 15% improvement (P < 0.05) in gain per unit of feed (G:F) . Steers produced in IS had a 5% greater (P < 0.05) live finished weight, 3.2% greater (P < 0.05) hot carcass weight, and 6% lower kidney, pelvic, and heart (KPH) fat (P < 0.05), than ES steers. There was no difference in marbling (P > 1.0) but there was a trend for ribeye area to be greater in IS steers than in ES (P = 0.14). Yield grade was 13% lower (P < 0.05) in IS Steers than in ES steers at 3.2 and 3.6 respectively. Postnatal grazing management system had a dramatic impact on summer feedlot entry weight, feedlot performance and carcass characteristics in a fall-calving system. Improved winter nutrient status when cows limit grazed and calves grazed wheat pasture ad libitum resulted in greater summer weaning weight followed by increased weight gain and feed conversion during the finishing phase.

Feed efficiency, ADG, carcass traits

© American Society of Animal Science 2016