烟酸对奶牛生理参数及生产性能影响的研究 3、烟酸对生产性能的影响

本研究由三个试验组成。试验一和试验二分别选用两个牧场处于泌乳早期的奶牛14头和12头,按照年龄、胎次、预产期和上胎305天产奶量分为试验组和对照组。试验三选用处于泌乳中后期的奶牛12头,按其年龄、胎次、分娩期和试验前7天产奶量分为两组,进行交叉试验。试验用奶牛精料根据《中国奶牛饲养标准》配制。试验组奶牛的烟酸添加量均为6克/头·日。 试验结果表明,试验一和试验二中添加烟酸奶牛的平均产奶量分别比对照组高1.74和1.18千克/头·日·(p<0.05)。试验一中试验组乳脂率比对照组高0.2个单位(p<0.05)。试验三中添加烟酸对奶牛的产奶量和乳脂率均无影响。三个试验中奶牛的精料采食量和体重变化两组间无显著性差异(p>0.05)。 本研究结果说明在奶牛泌乳早期日粮中添加烟酸,可以提高其产奶量和乳脂率。而对泌乳中后期奶牛的生产性能没有影响。

Studies on the Influences of Niacin on Physiological Parameters and Milk Production of Holstin Cows 3, Effect of Niacin Supplementation on the Performance of Lactating Cows

This purt was composed of three experiments. 14 and 12 dairy cows in early lactation were used and each was respectively paired into treatment and control groups balanced as 305-day yield of last lactation, age, No.of calving and calving dates of present lactation in Experiment 1 and 2 . 12 dairy cows in middle and late lactation were selected and divided into two groups in a double reversal trial.The treatment groups received niacin at 6g per head per day.The control groups received no niacin.The diet consisted of corn, wheat, wheat bran,soybean meal, cotton seed meal and minerals.The rations were formulated according to Chinese Feeding Standard of Dairy Cow. The results of three experiments were as follows. The milk yield of treatment groups was 1.74 and 1.18 kg/day greater than that of the control groups in experiment 1 and 2 (P<0.05). The milk fat increased 0.2 unit in experiment 1 C P<0.05 ) .Niacin supplementation had no significant effect on the performance of dairy cow in experiment 3 and feed intake and body changes in three experiments. The study illustrated that niacin addition, could improve the milk production and milk fat of the dairy cows in early lactation, but had no marked influence on the performance of the dairy cows in middle and late lactation.