Effects of Feeding Protease-treated Protein Feedstuffs on Milk Production and Blood Metabolites in Lactating Dairy Cows
The study was performed to evaluate the effects of soybean meal (T1) and corn distillers dried grains with solubles (DDGS, T2) hydrolyzed by microbial proteolytic enzyme of Protame® on milk production and protein contents in dairy cows. Total of nine Holstein cows (i.e., 1.67 ± 0.47 average parity and 23.7 ± 1.2 kg/d average milk yield) were randomly assigned to control, T1, and T2 (e.g., 3 animals per group) and treated for 4 weeks. Milk yield of 3 different groups was similar in the beginning of the study, however the milk yield of T1 and T2 treatment group had increased by 0.93 kg/d and 1.89 kg/d, respectively. Milk protein level of T2 treatment group was increased by 0.19% (e.g., 0.14 kg/d protein content), whereas there was no significant different in control and T1 group. In conclusion, blood metabolites were ranged in normal level, but BUN content was reduced from 19.03 mg/dl to 17.70 mg/dl in T2 treatment group. This result suggests that DDGS hydrolysate supplement efficiently increase milk yield and milk protein level as well as feed protein availability in dairy cattle.