单宁酸对奶牛采食量、乳成分及氮代谢的影响

Effects of tannic acid on feed intake,milk composition and nitrogen metabolism of dairy cows

文章旨在研究单宁酸对奶牛采食量、乳成分及氮代谢的影响。试验将产奶量一致的32头荷斯坦奶牛随机分为2组,每组4个重复,每个重复4头。对照组和处理组分别饲喂基础浓缩日粮及基础浓缩日粮+15g/kg单宁酸,整个21d的饲养试验期间奶牛自由采食水稻秸秆。结果 :与对照组相比,单宁酸组奶牛有机物和中性洗涤纤维摄入量分别显著提高17.54%和22.55%(P <0.05)。对照组与处理组奶牛泌乳量、4%脂肪校正乳及乳脂肪、蛋白、灰分、乳糖和非脂固形物占比均无显著差异(P> 0.05)。单宁酸奶牛的饲料效率较对照组显著降低11.26%(P <0.05)。与对照组相比,单宁酸组奶牛的氮摄入量、粪氮和尿酸排泄量及微生物蛋白合成量分别显著提高13.70%、13.45%、27.02%和17.19%(P <0.05),而对照组氮排泄与氮摄入量比值显著高于单宁酸组(P <0.05)。结论 :浓缩料中添加15g/kg单宁酸可在不影响奶牛生产性能的前体下提高氮摄入量,降低氮排泄占氮摄入量的百分比。

The experiment was conducted to study the effects of tannic acid on feed intake,milk composition and nitrogen metabolism of cows. Thirty-two Holstein cows with the same milk yield were randomly divided into 2 groups with 4 replicates per group and 4 cows per replicate.Dairy cows in control group and treatment group were fed basal concentrate diet and basal concentrate diet +15 g/kg tannic acid,respectively. During the whole 21 days of feeding experiment,dairy cows were free to eat rice straw.Results :Compared with control group,organic matter and neutral detergent fiber intake of dairy cows in tannic acid group were significantly increased by 17.54% and 22.55%(P < 0.05),respectively.There were no significant differences in milk yield,4% fat corrected milk and the proportion of milk fat,protein,ash,lactose and non-fat solid between control group and treatment group(P > 0.05).Compared with the control group,the feed efficiency of tannic acid dairy cows was significantly decreased by 11.26%(P < 0.05).Compared with the control group,nitrogen intake,fecal nitrogen and uric acid excretion and microbial protein synthesis of dairy cows in tannic acid group were significantly increased by 13.70%,13.45%,27.02% and 17.19%(P < 0.05),respectively,while the ratio of nitrogen excretion to nitrogen intake in the control group was significantly higher than that in the tannic acid group(P < 0.05). Conclusions :Supplementation of 15 g/kg tannic acid in concentrated feed can increase nitrogen intake and reduce the percentage of nitrogen excretion in nitrogen intake without affecting the performance of cows.