26 Effects of restricted feeding on growth performance and carcass characteristics in finishing beef steers.

Abstract Limit feeding is a management technique that can increase gain efficiency in growing and finishing beef cattle. We evaluated the effects of restricted DMI by 0, 4, 8, or 12% of slick bunk management on growth performance and carcass characteristics of finishing beef steers. Yearling crossbred steers were received in 2 source groups and sorted into BW blocks within source blocks (source 1 = 7 BW blocks, source 2 = 7 BW blocks). Steers were assigned randomly to treatment pens within BW block (n = 56 pens total; 4 steers/pen; 14 blocks). On d 0, individual BW was measured before feeding (initial BW = 387 ± 7.4 kg). Treatments included: 100R = cattle managed using slick bunk to target no residual feed at 0730 h; 96R = 4% restriction of slick bunk; 92R = 8% restriction of slick bunk; and 88R = 12% restriction of slick bunk. Feed offered for 96R, 92R, and 88R was adjusted weekly based on the previous 7-d average of the 100R treatment. Pen was the experimental unit for all variables. Continuous data were analyzed using mixed models, and categorical data were analyzed as binomial proportions. The model included treatment as a fixed effect and BW block nested within source block as a random effect. By design, DMI decreased with increased degree of restriction (P < 0.01). Final BW and ADG were greater for the 100R and 96R than the 92R and 88R (P ≤ 0.05). Hot carcass weight, marbling score, and empty body fat were greater for the 100 and 96R than 92 and 88R (P ≤ 0.04). A key observation of this study was no difference in ADG (1.33 kg/d; P = 0.86) for the 96R and 100R, resulting in a tendency for 96R to have a 6% increase in gain:feed (P = 0.07). Additionally, fat thickness, longissimus muscle area, and USDA yield grade and quality grade distribution did not differ among treatments (P > 0.12). These data suggest that restricting feed intake by 4% does not hinder growth performance or carcass characteristics in finishing beef steers.