Implications of Fat-Feeding Practices for Lactating Dairy Cows - Effects on Milk Fat

摘要

Feeding a variety of fat sources (e.g. oil seeds, tallow, yellow grease, fish oil, and ruminally inert fats) can increase milk yield of dairy cows if managed well. Milk fat depression is thought to be caused by a reduced synthesis of fatty acids by the mammary gland due to the formation of trans fatty acids synthesized by ruminal microbes in a more acidic ruminal environment in the presence of mono- and/or polyunsaturated fatty acids. Cows consuming diets that contain corn silage as the only or majorforage source are susceptible to milk fat depression. Partial substitution of corn silage with another forage such as alfalfa may alleviate this negative effect by making the rumen less acidic. It is not necessary to wait until cows have calved in order to initiate fat supplementation.