复合酶制剂对瘤胃发酵及泌乳早期奶牛生产性能的影响

本试验旨在研究添加不同水平复合酶制剂对瘤胃发酵及奶牛生产性能的影响。试验一以奶牛全混合日粮作为底物进行体外瘤胃发酵试验,分为4组,即对照组不添加酶制剂,试验1、2和3组的酶制剂添加量分别为日粮浓度的0.10%、0.15%和0.20%,每组设9个重复。每个重复准确称取0.500 g底物,在体外发酵产气自动记录装置上发酵48 h,测定其发酵参数和营养物质降解率。结果表明:复合酶制剂显著提高发酵液中总挥发性脂肪酸和乙酸浓度(P<0.05);试验组中粗蛋白(P<0.05)和中性洗涤纤维(P<0.01)降解率显著高于对照组。试验二选择体重、胎次、泌乳天数和产奶量相近的泌乳早期荷斯坦奶牛36头,采用随机区组设计分为4组,即对照组和试验1、2和3组,对照组不添加酶制剂,试验1、2和3组分别添加0.10%、0.15%和0.20%的酶制剂,每组9个重复,试验期8周,测定产奶量和乳成分含量,计算3.5%乳脂校正乳。结果表明:复合酶制剂显著提高3.5%乳脂校正乳产量(P<0.05),0.10%、0.15%和0.20%组比对照组分别提高3.88、4.27和2.26 kg·d^-1。0.15%组的乳脂率显著高于对照组(P<0.05),比对照组高12.7%。结论添加复合酶制剂有利于瘤胃发酵和提高生产性能,且添加量为0.15%时效果较好。

Effects of complex enzyme on rumen fermentation and milk production in early lactation dairy cows

Two experiments were conducted to evaluate the effects of different levels of complex enzyme on rumen fermentation and milk production in early lactation dairy cows.The first experiment evaluated rumen fermentation in vitro with total mixed ration (TMR) as substrate.There were four treatments,with complex enzyme supplementation at concentrations of 0,0.10％,0.15％ and 0.20％.Each treatment had 9 replicates and each replicate consisted of 0.500 g accurately weighed substrate.The degradation rate of nutrients in the substrate and in vitro fermentation parameters were determined with an in vitro fermentation gas automatic recording device within 48 h.Results showed that the complex enzyme significantly increased total volatile fatty acids and acetic acid in fermentation fluids (P＜0.05).The degradation rates of neutral detergent fiber (P＜0.05) and crude protein (P＜0.01) in the supplemented treatments were significantly higher than in the control.The second experiment was conducted using a randomized complete block design with thirty-six Holstein dairy cows of similar body weight,parity,days in milk and milk yield.Complex enzyme was supplied to four treatments at concentrations of 0,0.10％,0.15％ and 0.20％ respectively.Each treatment had 9 replicates and the experiment lasted for 8 weeks.Milk yield,milk composition content and 3.5％ fat-corrected milk were measured.The results showed that complex enzyme significantly increased 3.5％ fat-corrected milk (P＜ 0.05).For the 3.5％ fat-corrected milk,the 0.10％,0.15％ and 0.20％ treatments were 3.88,4.27 and 2.26 kg · d-1 more than the control respectively.The milk fat rate in the 0.15％ treatment was significantly higher than the control (P＜0.05),with a 12.7％ increase.In conclusion,adding complex enzyme can affect rumen fermentation and production performance.The results suggest that the optimal compound enzyme level in TMR is 0.15％.