Effect of replacing feed grains by food by-product on energy metabolism of lactating cows

The lactating cow requires a large amount of energy for milk production. Thus, it is important to clarify and satisfy the cow’s energy requirement for milk production. Additionally, it is also critical to improve the efficiency of energy utilization for milk production to reduce both cow’s metabolic load and feed costs. We have begun work to estimate the impact of roughage to concentrate ratio in the diet on energy metabolism of the lactating cow at the whole-body and mammary gland level. In this experiment, the energy efficiency for milk production from cows fed diets which contained 45% roughage and either feed grains or a by-product were examined.