Effects of compound probiotics on milk performance and rumen fermentation parameters of Holstein dairy cows in middle-and-later lactation / 中国兽医学报

ABSTRACT

The aim of this study was to evaluate the effects of compound probiotics on milk performance,blood biochemical indexes,rumen fermentation parameters and nutrient digestibility of Holstein dairy cows in middle-and-later lactation.Forty-eight dairy cows with similar milk yield,days in milk and age were randomly divided into 4 groups treated with four different levels of compound probiotics as followsthe control group (0 g/d),group 1 (10 g/d),group 2 (20 g/d) and group 3 (30 g/d).The adaptation period was 7 days,and the total experimental period was 60 days.Results showed thatcompared with the control group,supplementation of compound probiotics could improve milk yield and significantly increase the concentration of milk protein,lactose and total solids (P＜0.05);there was no significant effect on blood biochemical indexes (P＞ 0.05);compound probiotics could significantly increase the content of ammonia and microbial protein content (MCP) in the rumen (P＜ 0.05);the apparent nutrient digestibility of crude protein and crude fat of group 2 was significantly higher than other groups (P＜0.05);compared with the control group,the economic benefits of group 1,2,3 increased 2.28,4.80 and 4.09 yuan/d,respectively.In summary,dietary supplementation with 20 g/d of compound probiotics was the most effective method for milk performance,rumen fermentation parameters,nutrients apparent digestibility and economic benefit of Holstein dairy cows.