Effects of supplementing xylose-treated soybean meal or untreated corn gluten meal to lactating dairy cows.

This experiment was performed to investigate whether feeding xylose-treated soybean meal (XSBM) or corn gluten meal (CGM) is economically better under field conditions. Ninety-four multiparous early lactating Holstein cows (55±5 days in milk and 2.82±0.41 body condition score) were used in a completely randomized design. Cows were randomly assigned to one of two treatments: XSBM or CGM as the main rumen undegradable protein source in the diet. Dry matter intake (DMI), milk yield and fat corrected milk (FCM) were not affected by treatments. A tendency was detected for higher FCM: DMI (1.57 vs. 1.47) and income:cost (1.97 vs. 1.83) in CGM treatment. Milk urea nitrogen was greater (15.89 vs. 15.16 mg/dL) in the XSBM group. Plasma glucose, non-esterified fatty acid, beta-hydroxy butyric acid and albumin were not different between treatments. The results showed that under field conditions and feed ingredients used in this experiment, using CGM was economically beneficial during early lactation, which is in contrast with traditional beliefs.