Master of Science / Department of Animal Sciences and Industry / Joe D. Hancock / Three finishing pig and one broiler chick experiment were completed to determine the effect of diet formulation, mix time, and diet form on growth performance and carcass measurements. In Exp. 1, finishing pigs fed corn-soy diets had greater ADG, HCW, DP, and BF (P < 0.05) compared to pigs fed diets with 30% DDGS and 10% wheat middlings. However, increasing mix time from 60 to 420 s did not affect growth performance or carcass measurements (P > 0.38). In Exp. 2, pigs were fed diets with 32% DDGS and 32% wheat middlings and were mix for 0, 15, 30, 60, or 420 s. There were no differences in growth performance or carcass measurements as mix time was increased from 0 to 420 s (P > 0.06). In Exp. 3, pigs were fed 32% DDGS and 32% wheat middlings in meal and pelleted diets that were mixed for 0 or 180 s. Pelleting diets increased ADG and improved G/F (P > 0.01). Increasing mix time had no effect on ADG or G/F (P > 0.16) as mix time was increased from 0 to 180 s. There were no differences in carcass measurements because of diet form or mix time. In the final experiment (Exp. 4), broiler chicks were fed a corn-soy diet or a diet with 20% DDGS and 20% wheat middlings and mixed for 0, 15, 30, 60, and 300 s. Broiler chicks fed the corn-soy diet had greater G/F (P < 0.01) but increasing mix time from 0 to 300 s did not affect growth performance or carcass characteristics (P > 0.13). Increased mix time in diets with high levels of alternative ingredients does not affect growth performance or carcass measurements when fed to finishing pigs or broiler chicks.

Master of Science / Department of Animal Sciences and Industry / Joe D. Hancock / Nine experiments were completed to evaluate the effects of feed manufacturing practices on milling characteristics of diets and growth performance and stomach morphology in pigs. In Exp. 1 and 2, reducing the particle size of sorghum from 800 to 400 μm improved (P < 0.04) efficiency of gain in finishing pigs by 5% but had negative effects on cost of milling and stomach morphology. In Exp. 3 and 4, finishing pigs fed diets with 10 mg/kg of ractopamine HCl, had improved (P < 0.05) ADG, G:F, HCW, dressing percentage, and percentage carcass lean. However, increasing mix time of the diet from 0 to 360 s did not affect (P > 0.06) the response of finishing pigs to ractopamine HCl. In Exp. 5 and 6, adding ground and cracked corn to a pelleted supplement for nursery pigs decreased (P < 0.01) growth performance compared to feeding a complete pellet. In Exp. 7, increasing the percentage of cracked corn in a diet for finishing pigs decreased development of stomach lesions but also had a generally negative effect on efficiency of gain. In Exp. 8, adding cracked corn to a pelleted supplement (as done for the nursery pigs) decreased milling costs and improved health of stomach tissue. But, G:F was decreased by 6% (P < 0.05) which will make this technology unattractive to swine producers. In our final experiment (Exp. 9), pigs fed pellets tended to have the greatest growth performance, pigs fed mash the worst, and pigs fed pellets for only part of the grow-finish phase fell in between. In conclusion, grinding sorghum-based diets for finishing pigs improved efficiency of growth but extensive mixing to maximize diet uniformity had no effect on growth performance or carcass measurements. Use of cracked corn in diets does decrease diet costs and improve stomach health in finishing pigs but feeding of complete pellets for the entire finishing period supports maximum rate and (or) efficiency of gain.