Effect of Substituting Alfalfa by Wheat Straw Powder on Rumen Digestion, Metabolism and Production Performance in Lactating Dairy Cows

摘要

China has abundant straw resources. However, the straw has high levels of crude fiber, low levels of crude protein and fat, poor palatability and low digestibility and a large volume. This study explored the feasibility of using wheat straw powder to replace some of alfalfa and the suitable replacement ratio for lactating dairy cows. In this trial, cows in the mid-lactation stage were fed with rations in which alfalfa hay was replaced isocalorically and isonitrogenously at 0%, 20%, 40% and 60% by wheat straw powder to explore the rumen metabolism and production performance of lactating dairy cows. Using a large randomized block design, 60 cows were selected and divided into 4 groups: the positive control group CG (0% replacement), and groups AL (20% replacement), AM (40% replacement), and AH (60% replacement). The pre-feeding period was 2 weeks and the trial period was 8 weeks. Milk yield, milk protein yield, milk protein percentage, lactose yield, lactose percentage, milk fat yield, and milk fat percentage were not affected by the diets, and the differences among the groups were not significant (P > 0.05). The results show that replacing 20% alfalfa with wheat straw powder is most beneficial to production. When only the feed costs were considered, without considering other costs (such as labor, machinery, etc.) in the economic benefit calculation process, and assume that other costs are the same among the groups, and the economic benefits obtained by the AL group were the largest. The experimental results provide a basis for the further development of straw feed.