Effects of Cow-Calf Production System and Post-Weaning Management on Finishing Performance and Carcass Characteristics

Research has indicated that cornstalk grazing can be integrated into a semi-confined cow-calf production system. Furthermore, post-weaning management can affect finishing performance and carcass characteristics of beef cattle. The objective of this study was to evaluate cow-calf production system and post-weaning management on finishing performance and carcass characteristics of calves produced from a confined cow-calf production system. The study was conducted over 2 years. Cows with summer-born calves at side were assigned to 1 of 2 treatments: dry-lot feeding or cornstalk grazing with supplementation. Cow-calf pairs assigned to the dry-lot treatment were fed a distillers and corn residue-based diet, and pairs assigned to cornstalk grazing were supplemented with distillers-based cubes. Following the cornstalk grazing period from November to mid-April, all calves were weaned and received into the feedlot. Summer-born steer (n=78) and heifer (n = 60) calves (BW = 265 42 kg; 270 d of age) were allocated by previous cow-calf production system, stratified by initial BW, and assigned randomly to 1 of 2 post-weaning treatments with 2 replications per treatment. The treatment design was a 2 x 2 factorial arrangement. 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. Calves in the GROW treatment were placed on a growing diet for 76 days before being adapted to the common finishing diet. No significant interactions were observed between treatments (P ≥ 0.98) so main effects will be presented. Cattle were fed to a common compositional endpoint, and 12^th rib fat thickness did not differ among treatments (P ≥ 0.30). Calves from STALK had lighter initial BW entering the finishing phase than calves from DLOT (P = 0.02). However, there were no effects of cow-calf production system on final BW or carcass weight (P = 0.39). Calves in the FINISH treatment had greater ADG (P < 0.01) and improved G:F (P < 0.01); however, GROW calves had 32 kg greater final BW (P < 0.01) and 20 kg greater carcass weight (P < 0.01). An economic analysis would suggest that directly finishing calves results in greater net profit compared to growing calves prior to the finishing phase (P < 0.01) as the extra carcass weight did not offset the cost of the 76 d growing period.