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Abstract
An 84 d stocker trial was conducted to evaluate two corn by-products as CP supplements in corn silage-based stocker systems in the Southeastern United States. Eighty-one weaned steers (BW=306 kg± 56.69 kg) were stratified by weight and assigned to one of three corn silage based diets: 1) dried distillers grains plus solubles (DDGS), 2) corn gluten feed (CGF) or 3) soybean meal and ground corn (SBM). On d 0, 28, 56, and 84, measurements of BW, hip height, and BCS were recorded, also, ribeye area and intramuscular fat were assessed via ultrasound. During the stocker phase, steers fed SBM had increased BW (P<0.05) compared to cattle fed DDGS or CGF. Average daily gain was increased (P<0.05) for steers fed DDGS or SBM on d 28 compared to CGF, but by 84 d, ADG was similar among treatments (P>0.05). Corn gluten feed tended to decrease G:F (P=0.06) compared to DDGS and SBM. Cost per kg of gain tended to be less (P=0.07) for DDGS than for SBM or CGF. Measurements for BCS and hip heights did not differ (P>0.05) across treatment, but did increase over time (P<0.05). Ultrasound data indicated steers fed SBM had greater ribeye areas than those fed CGF and DDGS (P<0.05), and intramuscular fat was more abundant (P<0.05) in CGF fed calves than those fed DDGS or SBM. However, after 84 d of supplementation there was no difference among the treatments for rump fat thickness (P>0.05). These performance and predicted carcass advantages, combined with comparable economic efficiency, indicate that CGF and DDGS can be utilized in Southeastern stocker systems without substantially compromising economically important traits.