复合包膜甜菜碱对夏季奶牛产奶性能及血液生化指标的影响

选取36头泌乳中期的荷斯坦奶牛,随机分为3组,即基础对照组、试验Ⅰ和Ⅱ组,分别添加10、20和30 g.d-1复合包膜甜菜碱于奶牛全混合日粮中.于试验前、中期和后期在牛尾静脉采集血液,测定血液指标,研究复合包膜甜菜碱对夏季奶牛的产奶性能及血液指标的影响.结果表明:三组奶牛的产奶量差异不显著(P>0.05),Ⅰ和Ⅱ组的产奶量分别比基础对照组提高0.58和1.17 kg.d-1;三组奶牛乳脂含量、乳蛋白含量和体细胞数的变化均不明显,各组之间的差异均不显著(P>0.05);试验期间,三组奶牛血浆中的葡萄糖浓度较试验前均有增加,血浆中的乳酸脱氢酶、肌酸磷酸激酶和碱性磷酸酶活性均下降后上升;试验中期,Ⅱ组奶牛血浆中的总蛋白含量显著低于基础对照组(P<0.05);试验末期,Ⅰ和Ⅱ组奶牛血浆中的总蛋白和白蛋白含量低于基础对照组(P>0.05),Ⅰ组血浆中的尿素氮含量高于基础对照组(P>0.05),Ⅱ组尿素氮含量低于基础对照组(P>0.05).由于试验缺乏空白对照组,因此不同添加量的复合包膜甜菜碱对奶牛的产奶性能及与能量代谢有关的血液指标无显著影响,但Ⅱ组产奶量较高;与Ⅰ和Ⅱ组相比,基础对照组有积累血浆中总氮的趋势.

Effects of rumen protected betaine on milk production and blood biochemical parameters of dairy cow in summer

Thiry-six holstein dairy cows were randomly divided into three groups,which were basic control(add to 10 g·d-1 rumen protected betaine in total mixed rations),treatment Ⅰ(add to 20 g·d-1 rumen protected betaine) and treatment Ⅱ(add to 30 g·d-1 rumen protected betaine).The blood samples were collected from caudal vein with acid citrate dextrose in the tube before the test,the middle testing day and the last testing day.The blood plasma was storaged below-20 ℃ to analyze the level of gluose(Glu),creatine phosphate kinase(CPK),alkaline phosphatase(ALP),lactate dehydrogenase(LDH),total protein(TP),albmin(ALB),blood urea nitrogen(BUN).The result showed that there was no difference of milk yield and milk composition between basic control and treatments.But there were higher milk yield of 0.58 kg·d-1 in treatment Ⅰ and 1.17 kg·d-1 in treatment II than that in basic control.There was no significant difference of milk composition between basic control and treatments.In the test,the levels of Glu of three groups were higher than those before test,and the levels of LDH,CPK and ALP of three groups showed the decline in the middle testing day and recuperation in the last testing day.In the middle testing day,the level of TP of treatment Ⅱ was lower than that of basic control(P<0.05) and lower than that of treatment Ⅱ(P>0.05).The levels of TP of treatment Ⅰ and Ⅱ were lower than that of basic control(P>0.05) in the last testing day.The level of BUN of treatment Ⅰ was higher than that of basic control(P>0.05),and that of treatment Ⅱ was lower than that of basic control(P>0.05).Because of lack of control(with 0 g·d-1 betaine),the results showed that there was no significant difference of milk yield,milk composition and energy metabolism between basic control and treatments.And 30 g·d-1 rumen protected betaine in total mixed rations was better for milk production and 10 g·d-1 had a better effect on the retention of N than others.