Effects of Cow-Calf Production System and Post-Weaning Management on Finishing Performance and Carcass Characteristics of Calves Produced from an Intensively Managed Cow-Calf Production System

Research has indicated that corn residue grazing can be integrated into a partial intensively managed cow-calf production system. Furthermore, post-weaning management can affect finishing performance, as well as carcass characteristics of beef cattle. The objective of this study was to evaluate the effects of cow-calf production system and post-weaning management on finishing performance and carcass characteristics of calves produced from an intensively managed cow-calf production system. Cows with summer-born calves at side were wintered either in a dry-lot or on cornstalks. Cow-calf pairs in the dry-lot were fed a distillers and corn residue based diet formulated to maintain a lactating cow. Cow-calf pairs grazing cornstalks were supplemented with distillers based cubes at a rate designed to provide the cornstalk grazing pairs with an equivalent energy intake to that of the dry-lot pairs. Following the cornstalk grazing period from November to mid-April, all calves were weaned and received into the feedlot. Calves (n = 47; BW = 265 44 kg) were allocated by previous cow-calf production system, stratified by initial BW, and assigned randomly to one of four treatments with two replications per treatment. The trial was designed as a 2 x 2 factorial. Treatment factors included: 1) cow-calf production system: dry-lot feeding (DLOT) or cornstalk grazing (STALK) and 2) post-weaning management: finishing (FINISH) or pre-finishing growing (GROW). In the FINISH treatment, weaned calves were directly adapted to a finishing diet (50% HMC, 30% sweet bran, 10% MDGS, 5% wheat straw, and 5% supplement). Calves in the GROW treatment were placed on a growing diet (30% Sweet Bran, 35% MDGS, 31% wheat straw and 4% supplement) for 79 days before being adapted to the same finishing diet. Cattle were fed to a common compositional endpoint, and 12^th rib fat thickness did not differ among treatments (P > 0.70). No cow-calf production system by post-weaning management interactions (P > 0.22) were observed for finishing performance, nor was there a cow-calf production system effect on finishing performance or carcass characteristics (P > 0.10). Initial body weight, final body weight, corresponding HCW, and DMI were greater for cattle in the GROW treatment (P < 0.04). Cattle directly adapted to a finishing diet had greater G:F (P < 0.01). When harvested at similar back fat, cattle that were fed a growing diet prior to the finishing phase had 25 kg more HCW when compared to cattle that were directly adapted to a finishing diet.