牛至油和过瘤胃蛋氨酸组合添加对奶牛瘤胃微生物蛋白产量与养分消化率的影响

本试验旨在研究牛至油(Oo)与过瘤胃蛋氨酸(RPMet)的不同添加组合对奶牛瘤胃微生物蛋白(MCP)产量与养分消化率的影响。选取年龄、体重、胎次、产奶量、乳成分及泌乳期(90±15)d的荷斯坦奶牛40头,分为10个组,每组4头。对照(C)组饲喂基础日粮,试验组饲喂不同添加水平的Oo和RPMet,Oo设置3个梯度,添加量分别为11.5(L)、13(M)、14.5(H)g/(d·头);RPMet设置3个梯度,添加量分别为22.5(L)、25(M)、27.5(H)g/(d·头),共组成9个不同的添加量组合,分别为LL、ML、HL、LM、MM、HM、LH、MH、HH(第1个字母为Oo添加水平,第2个字母为RPMet添加水平)。预试期15 d,正试期60 d。结果表明:各试验组奶牛的微生物蛋白(MCP)产量均有提高,其中MH、ML、LH、LM、HM组的MCP产量显著提高;试验组奶牛的养分表观消化率有提高趋势,其中MH、HM组粗蛋白质消化率极显著提高;HH、MH组中性洗涤纤维消化率显著提高,酸性洗涤纤维消化率极显著提高;MH组干物质消化率显著提高。在本试验条件下,综合考虑瘤胃MCP产量以及各主要养分的表观消化率,以Oo 13 g/(d·头)、RPMet 27.5 g/(d·头)组合(MH组)效果最好。

Effects of Oregano Oil and Rumen-Protected Methionine on Rumen Microbial Protein Production and Nutrient Digestibility of Dairy Cows

This experiment was conducted to determine the effects of different combinations of oregano oil(Oo) and rumenprotected methionine(RPMet)on rumen microbial protein production and nutrient digestibility of dairy cows. Forty Holstein lactating dairy cows with similar age, body weight, parity, milk yield, milk composition and lactation period(90±15 days postcalving) were divided into 10 groups with 4 cows per group. Cows in control group(C) was fed a basal diet, and except the basal diet, cows in experimental groups were supplemented with different levels of Oo [11.5(L), 13(M) or 14.5(H)g/(d·head)] and RPMet [22.5(L), 25(M) or 27.5(H) g/(d·head)]. So 9 experimental groups were included, which was named as LL, ML, HL, LM, MM, HM, LH, MH and HH(first letter indicated Oo supplemental level, and the second letter indicated RPMet upplemental level), respectively. The pre-experiment lasted for 15 days, and the experiment lasted for 60 days. The results showed that rumen microbial protein production of the experimental groups were higher, and MH, ML, LH, LM, HM were significantly improved(P<0.05). nutrients digestibility of experimental groups were higher, the digestibility of CP in MH and HM groups were significantly increased(P<0.01). The digestibility of NDF in HH and MH groups were significantly increased(P<0.05). The digestibility of ADF in HH and MH groups were significantly increased(P<0.01). DM digestibility was significantly increased in MH group(P<0.05). In combination with various test indicators, under the present experimental conditions, the Oo 13 g/(d·head), RPMet 27.5 g/(d·head)(MH group)was the best combination.