【作者】 马玉霞；

【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， 2004， 硕士

【摘要】 本试验研究了保护性脂肪与苜蓿对热应激及低质粗饲料条件下奶牛的影响，并对其机制进行了初步探讨，为保护性脂肪和苜蓿在生产实践中的应用提供理论依据。z试验Ⅰ：选择2～4胎次泌乳中期的荷斯坦奶牛48头，按照配对试验分为4组，每组12头，各试验组基础日粮相同。Ⅰ组喂基础日粮，Ⅱ组喂基础日粮+400g脂肪酸钙，Ⅲ组喂基础日粮+2.5kg苜蓿干草，Ⅳ组喂基础日粮+400g脂肪酸钙+2.5kg苜蓿干草。正试期50d。结果表明：(1)在热应激条件下，脂肪酸钙和苜蓿干草可以减缓产奶量下降，试验Ⅱ组、试验Ⅲ组、试验Ⅳ组平均日产量比对照组提高12.6％、14.08％、26.31％，试验Ⅳ组与对照组差异极显著（P<0.01）。（2）试验期各组乳脂率平均值较试验前都有所上升，试验Ⅱ、Ⅲ、Ⅳ组分别上升了20.42%、16.41%和21.17％，对照组上升了10.13％，对乳中其它成分如乳蛋白、非脂固形物、乳密度等影响不大。（3）对血清激素水平的影响是：试验Ⅱ组、试验Ⅲ组和Ⅳ组试验期T3的水平较试验前分别提高1.65％、20.2％和17.82％，而对照组试验期较试验前下降2.27％，试验Ⅳ组与对照组试期相比差异显著（Ｐ<0.05）。参试牛血清中T4水平的变化情况与T3大致相同，试验Ⅱ组、试验Ⅲ组和试验Ⅳ组试验期T4的水平较试验前分别提高11％、4.42％和24.88％，对照组试验期较试验前下降9.91％，试验期各组T4水平差异均不显著（Ｐ>0.05）。试验Ⅱ组、试验Ⅲ组和Ⅳ组和对照组试验期与试验前血清中COR水平相比均有上升，差异均不显著（Ｐ>0.05），但试验Ⅱ组、试验Ⅲ组和Ⅳ<WP=8>组相对于对照组低6.06％、17.54％、10.37％。而PRL的水平较试验前都有上升，以第Ⅳ组上升最多，为34.54％，Ⅱ组和Ⅲ组为14.88％、11％，对照组为6.33％。脂肪酸钙和苜蓿干草可维持试验组血清中T3、T4含量稳定，减缓因热应激造成的血清中PRL的下降和COR的上升。（4）Ⅱ组、Ⅲ组和Ⅳ组比对照组每头奶牛每天多产奶分别为2.06、2.3和4.3kg/head?d,盈利分别为1.09、1.45和2.45Yuan/head?d在这几组中，经济效益Ⅳ组最佳，其次是Ⅲ组、Ⅱ组。试验Ⅱ：选择1～3胎次泌乳中期的荷斯坦牛10头，按照配对试验的思想分为对照组和试验组，两组的混合精料组成相同，粗饲料对照组为豆秸、玉米秸、花生秧和玉米淀粉渣，试验组以10kg苜蓿青贮替代等量粗饲料。正试期60d。结果表明：（1）对照组试验后比试验前体重下降了3.91％，而试验组试验后比试验前体重上升了5.64％。试验后奶牛体重试验组与对照组相比差异极显著（P<0.01）。因此，对奶牛饲喂苜蓿青贮，可以缓解低质粗饲料对奶牛造成的体况较差、体重下降的影响。（2）在整个试验期苜蓿青贮组干物质采食量高于对照组16.67％，且差异极显著（p﹤0.01）。（3）在试验期间，对照组日平均产奶量下降，苜蓿青贮组日平均产奶量上升，二者差异极显著(P<0.01)。（4）苜蓿青贮可以显著提高乳脂率（P<0.05），对乳蛋白、非脂固形物含量和乳密度影响不大。（5）苜蓿青贮可以带来明显的经济效益，试验组牛比对照组牛净增收入6.38Yuan/ head?d。试验Ⅲ：在奶牛小区分别从农户A、B选择1～3胎次泌乳前期的荷斯坦牛10和4头，按照配对试验分为两组，对照组喂基础日粮，试<WP=9>验组喂基础日粮+300g保护性脂肪。正试期50d。试验组与对照组相比：（1）干物质采食量提高了7.17％，且差异极显著（p﹤0.01）；（2）产奶量提高了9.69％，且差异极显著（P<0.01）；（3）乳脂率增加了0.19个百分点（P<0.05），乳蛋白率下降了0.02个百分点（P>.05），其它乳成分指标基本无变化；（4）血清中葡萄糖下降了6.03％，尿素氮增加了4.08％，α-羟丁酸脱氢酶下降了13.05％，但差异都不显著（P>0.05），说明保护性脂肪对奶牛血液代谢物质无显著影响；（5）每头牛日产奶量增加2.23kg,盈利增加了 1.35 Yuan/ head?d。更多还原

【Abstract】 This paper studied the effect of hyprofat and alfalfa on cattles under heat-sressed condition or with low quality roughages ,the mechanisms were also initially concerned.In experiment I,48 Holstein dairy cows were randomly divided intoGroupⅠ (controlgroup),Ⅱ,ⅢandⅣ, according to their parturition numbers, milk yield and lactation period. The test lasted 50 days, during which GroupⅡwas added with 400g hyprofat, GroupⅢwas supplemented 2.5kg alfalfa hay ,400g hyprofat and 2.5kg alfalfa hay were added to groupⅣat the same time, while there was nothing addition in the control concentrate. The results showed:(1) feeding hyprofat and alfalfa hay could lessen the decline tendency of milk yield which were raised respectively by 12.6%、14.08%、26.31%（p﹤0.01） compared with the control.(2) The milkfat percentage of GroupⅡ,ⅢandⅣwere raised respectively by 4.91%,15.34%, 14.11% compared with the control. Lactoprotein, SNF and density had little change.(3) T3 levels of the serum of GroupⅡ,ⅢandⅣwere all increased by 7.56%,13.95%and 19.19%（p﹤0.05）compared with the control. The change of T4 level of the serum was same to which of T3. T4 levels of the serum of GroupⅡ,ⅢandⅣwere all raised by 14.49%,14.5%and 27.39%（p﹤0.05）compared with the control. COR level of the serum of GroupⅡ,ⅢandⅣ was decreased by 6.06%,17.54%and 10.37% compared with the control. PRL level of the serum of GroupⅡ,ⅢandⅣ was raised by8.55%,5.02% and 20.58% compared with the control.(4)Milk yield of GroupⅡ,ⅢandⅣ was increased respectively by 2.06kg/head/day,2.3 kg/head/day and 4.3 kg/head/day.In a year(305 days)the milk yield would be raised 628.3kg,701.5kg and 1311.5kg.The added profit would be 397.85yuan,442.3yuan and 747.25yuan.GroupⅣcould achieve the greatest profit.In experiment II,10 Holstein dairy cows which parturition numbers was from 1 to 3 were randomly divided into Group I(control group), Group II according to their parturition numbers, milk yield and lactation period. The test lasted 60 days.The two groups had the same concentrate.The roughage of control group was composed of soybean straw,corn straw and peanut vine,while that of Group II was made of alfalfa silage. The results showed:(1)The alfalfa silage group increased the DMI by 16.67% compared with the control. There was significant difference between them( p﹤0.01).(2)The milk yield was significantly raised by feeding alfalfa silage (p﹤0.01).(3)The milkfat percentage was significantly raised by feeding alfalfa silage (p﹤0.05).There was little change in lactoprotein, SNF and density.(4)Alfalfa silage could achieved great profit. In a year(305 days)the milk yield of a cow fed with alfalfa silage would be raised by 2516kg,the added profit would be 1945.9yuan. <WP=65>In experiment III,10 and 4 Holstein dairy cattles which were in early lactation were respectively chosen from two farmers.The 14 Holstein dairy cows were randomly divided into Group I(control group), Group II according to their parturition numbers, milk yield. Group II was supplemented 300g hyprofat while there was no addition in the control group. The test lasted 50 days. The results showed:(1) DMI of Group II was significantly increased by 7.17%( p﹤0.01).(2) The milk yield of Group II was raised by 9.69%( p﹤0.01).(3) The milkfat percentage Group II was raised by 0.19%( p﹤0.05).The lactoprotein decreased by 0.02% compared with the control group ,and SNF,milk density had little change.(4)The level of GLU and HBDH of the serum were respectively decreased by 6.03%,13.05% by hyprofat as compared with the control group. The level of BUN of the serum was increased by 4.08%.There was no significantiy difference between the two groups.(5) The milk yield of the hyorofat group could be raised by 2.23kg/head/day.In one year(305 days),there would be added 813.9kg/head,and the added profit would be 411.75yuan.更多还原