日粮粗精比对奶牛瘤胃液和血清乙酸、丙酸、丁酸的影响

Effects of forage to concentrate ration on rumen fluids and acetate,propionate and butyrate in serum of lactating dairy cows

【目的】研究不同日粮精粗比条件下奶牛瘤胃pH,挥发性脂肪酸(VFA,主要包括乙酸、丙酸、丁酸)浓度和血清乙酸、丙酸、丁酸浓度的动态变化规律。【方法】选用5头健康的干奶期荷斯坦奶牛(体重(502±25)kg),饲喂精粗比(质量比)分别为30∶70、35∶65、40∶60、45∶55、50∶50、55∶45、60∶40、70∶30和100∶0的9种日粮,对奶牛瘤胃内pH、VFA和血清VFA浓度进行检测。对5头奶牛连续进行9期饲喂试验,前8期试验每期30 d,最后一期试验为3 d。【结果】随日粮中精料比例的提高,奶牛瘤胃pH逐渐降低,其中饲喂精粗比为100:0日粮组的奶牛瘤胃pH显著低于其他精粗比日粮(P<0.05);精粗比为55∶45日粮组的奶牛瘤胃乙酸、丙酸和丁酸浓度,显著低于粗精比为30∶70、35∶65、40∶60、45∶55日粮组(P<0.05);精粗比50∶50日粮组奶牛血清乙酸浓度显著低于粗精比为30∶70、35∶65和100∶0日粮组(P<0.05);不同精粗比日粮条件下,奶牛血清丙酸和丁酸浓度组间差异不显著(P>0.05);血清乙酸和丁酸浓度与瘤胃中乙酸、丁酸浓度无明显相关性(P>0.05),但血清丙酸浓度与瘤胃丙酸浓度间呈极显著负相关性(P<0.01)。【结论】不同精粗比日粮对奶牛瘤胃pH、VFA和血清丙酸具有显著影响,奶牛在饲喂过程中逐渐对精料产生了耐受性,获得了稳定的瘤胃生态系统。

[Objective] The research studied dynamic changes of rumen pH and VFA , serum acetate, butyrate and butyric acid concentrations. [Method] Five healthy cows during the dry period were used to study the effects of forage to concentrate ration on dynamic change of rumen pH and VFA in rumen and serum. Cows were fed continuously in nine experiment periods with 30 d in each period except the last one with only 3 d. Dietary forage to concentrate ration were 30 ： 70,35 ： 65,40 ： 60,45 ： 55,50 ： 50,55 ： 45, 60 ： 40,70 ： 30,100 ： 0 concentration respectively. [Result] Rumen pH was down gradually with the in crease of forage to concentrate ration and tended to be the lowest in 100：0 concentration（P〈0.05）. Serum acetate were significantly lower （P〈0.05） in 50 ： 50 compared with 30 ： 70,35 ： 65 and 100 ： 0 concentra tion. Serum propionate and butyrate were not significantly different（P〉0. 05）. No relationship was observed between rumen acetate, butyrate and acetate, butyrate in serum（P〉0. 05 ）, while the relationships between rumen propionate and serum propionate reached extremely significant（P〈0.01）. [Conclusion] Dif to concentrate rations have notable effects on rumen pH, VFA and propionate in serum, the tolerance and established stable rumen ecosystem with the increase of forage to concentrate ferent forages cow obtained ration.