Microbes such as these two protozoa produce enzymes in the cow’s rumen — or four-chambered stomach — that break down fiber in fermentation that allows the animal to digest grasses. Researchers are trying to supplement additional enzymes to enhance the important symbiotic process going on between the microbes and the cow, resulting in improved milk production. Credit: U.S. Department of Agricultural. All Rights Reserved.
研究結果は Journal of Dairy Science 誌に掲載され、対照群に比べ、酵素を摂取した牛はより多く食べる傾向があり、牛乳にはタンパク質、乳糖、その他の望ましい固形分がより多く含まれていたと報告された。
アスペルギルス属菌の混合培養物から抽出した外来酵素製剤が初産牛および多産牛の泌乳成績、代謝および消化率に及ぼす影響について Effects of an exogenous enzyme preparation extracted from a mixed culture of Aspergillus spp. on lactational performance, metabolism, and digestibility in primiparous and multiparous cows
L.F. Martins,J. Oh,,M. Harper,A. Melgar,S.E. Räisänen,X. Chen,K. Nedelkov,T.P. Karnezos,A.N. Hristov
Journal of Dairy Science Published:July 22, 2022
The objective of this study was to investigate the effects of an exogenous enzyme preparation from Aspergillus oryzae and Aspergillus niger on lactational performance of dairy cows. Forty-eight Holstein cows (32 primiparous and 16 multiparous) averaging (± SD) 36.3 ± 8.7 kg/d milk yield and 141 ± 52 d in milk were enrolled in a 10-wk randomized complete block design experiment (total of 24 blocks) and assigned to 1 of 2 treatments: basal diet, no enzyme supplementation (CON) or the basal diet supplemented with 4.2 g/kg dry matter intake (DMI) of an exogenous enzyme preparation containing amylolytic and fibrolytic activities (ENZ). After a 2-wk covariate period, premixes with the enzyme preparation or control were top-dressed daily by mixing with approximately 500 g of total mixed ration. Production data were collected daily and averaged by week. Milk samples were collected every other week, and milk composition was averaged by week. Blood, fecal, and urine samples were collected over 2 consecutive days at 0, 4, 8, 12, and 36 h after feeding during the last week of the experiment. Compared with CON, cows fed ENZ tended to increase DMI and had increased milk concentrations of true protein, lactose, and other solids. Milk fat content tended to be higher in CON cows. A treatment × parity interaction was found for some of the production variables. Primiparous cows receiving ENZ had greater yields of milk, energy-corrected milk, milk true protein, and lactose compared with CON primiparous cows; these production variables did not differ between treatments for multiparous cows. Intake and total-tract digestibility of nutrients did not differ between treatments. Concentrations of blood glucose and total fatty acids were not affected by ENZ supplementation, but β-hydroxybutyrate concentration tended to be greater in ENZ cows. Overall, the exogenous enzyme preparation used in this study increased milk protein and lactose concentrations in all cows, and milk production in primiparous but not multiparous cows. The differential production response between primiparous and multiparous cows was likely a result of a greater increase in DMI with ENZ supplementation in the younger animals.