【作者】 李梦云；

【导师】 高腾云；

【作者基本信息】 河南农业大学 ， 动物营养与饲料科学， 2003， 硕士

【摘要】 本试验研究了在中原农区传统的粗饲料饲养奶牛条件下，放牧补饲牧草对奶牛生产性能的影响，以及粗饲料条件下奶牛的泌乳与补饲的关系，并进一步阐明牧草的补饲替代率及最佳补饲期和粗饲料的补饲及补饲替代率。以期在奶牛生产中有一定指导作用。 1．放牧对奶牛体增重和奶牛产奶性能的影响 选择体质健康，体重、年龄、胎次及产奶量基本相近的产后10周的成年荷斯坦奶牛12头，然后随机等数分配到对照组和试验组。对照组奶牛喂以粗料和精料，并进行舍饲，试验组除了喂粗、精料外(粗、精料的配方与对照组相同)，每天上午、下午在黑麦草和白三叶混播草地上放牧。试验期为2002年4-11月。试验始、末分别于早晨对每头牛空腹称重，每月测定各牛的粗、精料采食量、放牧采食量、产奶量和分析奶成分。结果表明，试验组和对照组奶牛平均每头增重分别为69和73kg，但二者差异不显著(P＞0.05)，说明放牧补饲对奶牛的体增重无显著影响。 在产奶量方面，整个试验期试验组奶牛平均产奶量稍高于对照组，但差异不显著(P＞0.05)。其中，4、5月份放牧组产奶量显著高于舍饲组，6、8、9、10、11月，放牧组和舍饲组的产奶量接近。 在乳成分方面，试验组乳脂率显著高于对照组(P＜0.05)；试验组乳蛋白含量高于对照组，其中7月份试验组的乳蛋白含量显著高于对照组(P＜0.05)。另外，试验组乳蛋白含量波动幅度较小，而对照组乳蛋白含量波动幅度较大；试验各阶段放牧组和试验组牛奶的密度在试验各阶段均无显著差异(P＞0.05)；试验组乳糖低于对照组，但差异不显著(P＞0.05)。这说明放牧对乳密度和乳糖的含量的影响不 2．放牧采食量、补饲替代率和最佳补饲期 牧草中 CP含量随着牧草的生长，分别在 6月份门．7 3们和 10 月份Q1．04们出现了两个峰值；而在7月份门2．24肋和n月份 （13．04％）达到最低。牧草中 ADF含量，分别在 7月份（24．00％）和 11月份＊1．80肋出现了两个峰值；而在9月份门．4肋达到最 低。奶牛的放牧采食量有逐月降低的趋势，只是7月份的放牧采食量 突然降低，到8月份，由于白三叶的增多和气温回落（月平均气温为 26．6 oC人 使奶牛的放牧采食量又增加。9、10、11 月份又随着牧草 的衰老和产奶量的降低，奶牛的放牧采食量又逐渐降低。 牧草的补饲替代率，以 7、10、11月份牧草的补饲替代率较高， 分别为0．73、0．65、0．70，这说明这三个月的牧草补饲效果不理想； 而以5、6月份的为最低，均为0．45，这说明这H个月的牧草补饲效 果很好；4、8、9月份，牧草的补饲替代率分别为 0．sl、0．58、0．61， 说明这三个月的牧草补饲效果较理想。 3．舍饲秸秆的补饲与补饲替代率 选取体重、产奶量、胎次、泌乳期基本一致，产奶8周以上的健 康成年荷斯坦奶牛20头，分成A、B、C、D、E五个试验组，各处理 组每头奶牛每天的精料补充量分别为：6、7、8、9、10kg，玉米青贮 自由采食，花生秧定量供应 4．2 kg／日．头。结果表明，不同的精料 水平对奶牛体增重、玉米青贮干物质采食量和乳脂率无显著影响，干 物质采食量、标准乳产量随着精料水平的增加而增加。粗饲料的补饲 替代率随精料水平的不同而变化，以每头奶牛每大的精料补充量为 gkg时，替代率最为理想。更多还原

【Abstract】 This paper studied the effect of grazing on milk performance of dairycow and further discuss the substitution rate of the herbage as well as the optimumgrazing periods under the condition of traditional feeding dairy cows model in Henanprovince.1.The effect of grazing on body weigh gain and productive performance for dairycowsChose 12 healthy, 10 weeks after parturition Holstein dairy cows which had resemble body weigh, age,parity, and milk yield, then divided them into experiment group(EG) and control group(CG) at random. There were six dairy cows in each group. The dairy cows of CG were fed with roughage and concentrate, the dairy cows of EG, besides feeding with roughage and concentrate (the formulation is the same as CG), grazed in the mixed sward of perennial ryegrass and white clover every mornings and afternoons. The experiment was conducted from April to November, 2002. Individual body weigh was measured before and after test, and individual roughage intake, concentrate intake, herbage intake, milk yield and composition of milk were measured every month respectively.Form this experiment, it can be concluded that during the experiment period, body weights increased in both groups, the average body weight gain of EG and CG are 69 and 73kg respectively, and there was no significant difference between them (P>0.05). This suggests that grazing don’t have significant effect on the body weigh gain.The total milk yield during experimental period for EG were 4421.17kg/cow, slightly higher than that for CG cows (4395.00 kg/cow), there was no significant difference between them (P>0.05). During the test period, the milk yield of EG is also significant higher than that of CG in April and May (P<0.05), whereas the resultwas adverse between them in July. The milk yield for EG and CG don’t have significant effect in June, August, September, October, and November (P>0.05).The milk fat percentage of EG is significant higher than that of CG (P<0.05); The milk protein percentage of EG in July is significantly higher than that of CG(P<0.05), but in the rest test period, there is no significant difference between them(P>0.05). In addition, the milk protein percentage of EG have little change and there is no significant difference among the test periods, whereas the milk protein percentage of CG changes greatly, especially the result of July and September differs significantly(P<0.05), which indicates that the milk protein percentage of EG is steady.During the test periods, there is no significant difference of milk density between EG and CG(P>0.05);The milk lactose percentage of EG is slightly lower than that of CG, and there is no significant difference between them(P>0.05), which suggests that grazing has little effect on milk density and milk lactose percentage. 2.the supplement herbage intake and the substitution rate of herbage were measured , and thus indicate the optimum grazing periodsThe nutritive content of herbage changes with its growth period. The CP content of herbage has two summits along with its growth period. From April to June, The CP is increasing and get the first summit in June (15.73%), then has the lowest point in July (12.24%). From August, The CP is increasing again and get the second summit in October (21.04%). From November, the CP content of herbage quickly decreases to 13.04%.The ADF of herbage also has two summits along with its growth period. From April to July, the ADF is increasing and get the first summit in July (24.0%). After July, it begins to decreasing and get its lowest point in September(12.4%), then rise from September to October, and get the second summit in November (21.8%).The herbage intake of grazing reduces month by month, but in July it reduces suddenly and get its lowest point. In August, because of the temperature decreasing and plenty of white clover available, the herbage intake increases again, but decrease in September, October and November with the herbage decaying and milk yield decreasing.The substitution rate of her更多还原