| dc.description.abstract | A series of experiments was designed to aid in developing optimal solutions for intensive cow-calf production. In the first experiment, we studied potential system limitations regarding inclusion and intake of grain and their effects on risk of digestive upset. Ruminal pH declined rapidly when concentrate diets were fed at high intake levels, but the minimal risk of acidosis observed at high intakes was mitigated through intake restriction. Next, we quantified interactions between dietary energy density and intake on energy digestibility to more accurately predict energy supplies. When high-energy diets were limit-fed to maintenance intake, more complete digestion leads to under estimation of DE intake. In the third experiment, we measured effects of dietary energy density and intake on apparent energy requirements. Divergence between observed and predicted energy retention was observed, suggesting that increasing energy density and restricting intake improved energy metabolism. Finally, in a study involving two experiments, we determined the effects of intake restriction on mass and metabolism of metabolically active organs to determine their role in a cow’s ability to adapt under periods of energy deficiency. Dietary energy restriction reduced the mass of metabolically active organs. Overall, limit-feeding high-energy diets to beef cows appears to provide opportunities for increased efficiency of land and feed energy use, with minimal risks to animal health. Previous nutrition models neglect to account for effects of intake restriction on energy metabolism, causing an overestimation of feed requirements for intensively-managed beef cows. | en |
