柴胡提取物对热应激奶牛营养物质表观消化率和瘤胃发酵参数的影响
Effect ofbupleurum extract on nutrient apparent digestibility and rumen fermentation parameters in heat-stressed Holstein dairy cows

为研究添加不同水平的柴胡提取物对热应激条件下泌乳后期荷斯坦奶牛营养物质表观消化率和瘤胃发酵参数的影响,采用随机区组设计,按照产奶量、泌乳天数及胎次相同的原则将48头荷斯坦奶牛随机分为4组,每组12头,各组在基础日粮中分别添加0、0.5、2.5和5.0 g/kg柴胡提取物(干物质基础),试验期9周。结果表明:热应激条件下,柴胡提取物对瘤胃pH,氨氮含量,丙酸、异丁酸、丁酸、异戊酸和戊酸浓度,乙酸/丙酸及营养物质表观消化率均无显著影响(P>0.05);0.5 g/kg组的菌体蛋白含量显著高于2.5和5.0 g/kg添加组(P<0.05),添加5.0 g/kg柴胡提取物降低瘤胃总挥发性脂肪酸(P=0.05)和乙酸浓度(P=0.06),不利于瘤胃发酵。因此,柴胡提取物推荐添加剂量不宜超过5.0 g/kg。
Experiment was conducted to study the effect of bupleurum extract (BE) on nutrient apparent digestibility and rumen fermentation parameters in heat-stressed Holstein dairy cows.Forty-eight cows were randomly assigned to one of four groups (n=12) based on DIM,milk yied and parity.Bupleurum extract was supplied into daily basal diet at 0,0.5,2.5 and 5 g/kg (Dry matter basis).The experiment lasted for 9 weeks in hot summer.The results showed:There were no effects on pH,the content of ammonia nitrogen,acetate/propionate,the concentrations of propionate,isobutyrate,butyrate,isovalerate and valerate,the diet apparent digestibility among different treatments (P>0.05);supplemental BE at 0.5 g/kg increased bacterial protein content (P<0.05) compared with 2.5 or 5 g/kg BE (P<0.05) andsupplemental BE at 5g/kg could decrease the concentrations of acetate and total volatile fatty acids,which reduced rumen fermentation.In conclusion,bupleurum extract recommended the additive dosage of BE should not be more than 5 g/kg.