【作者】 张荣飞；

【导师】 沈赞明；

【作者基本信息】 南京农业大学 ， 基础兽医， 2004， 硕士

【摘要】 本文目的在于寻求缓解高温季节奶牛热应激的新途径。系列一 半胱胺盐酸盐对高温季节泌乳后期奶牛生产性能和内分泌的影响：试验采用泌乳后期荷斯坦奶牛96头，根据热应激期前的产奶量（M）划分4个产量组，每组再划分为半胱胺盐酸盐处理（CSC，n=49），泌乳中期曾接受（CSC）与对照（n=47）。试验期（2个月）内牛舍温湿指数（THI）高于76，奶牛处于热应激状态。与对照相比，第一产量组（M＜24 kg／d）CSC奶牛体温降低（P＜0.05）。常乳、标准乳及饲料转化效率提高（P＜0.05）、乳脂率增加（P＜0.05），乳蛋白量倾向增加（0.05＜P＜0.15）；体细胞数趋于降低（0.05＜P＜0.15）。所有参试奶牛（n=49）血清中胰岛素浓度显著提高（P＜0.01），T₃、T₄浓度有降低趋势（0.05＜P＜0.15）。系列二 半胱胺盐酸盐对高温季节泌乳中期奶牛生产性能和内分泌的影响：试验选用30头泌乳中期荷斯坦奶牛，根据热应激前1周平均产奶量，将牛群分为对照（n=15）和半胱胺盐酸盐处理（CSC，n=15）两个组，CSC组每日添加半胱胺盐酸盐30g／d·head，对照组以常规饲喂方法饲喂，不添加半胱胺盐酸盐。试验期（2个月）内牛舍平均温湿指数（THI）高于79，奶牛处于严重热应激状态。结果表明，CSC组奶牛标准乳、乳脂提高（P＜0.05），常乳、饲料转化效率倾向增加；血清中T₃水平降低（P＜0.05），T₄有降低趋势（0.05＜P＜0.15），表明半胱胺盐酸盐对高温季节泌乳中期奶牛具有同样的作用效果。上述结果表明，半胱胺盐酸盐改善高温季节高产奶牛奶产量和乳品质，提高饲料利用效率，其影响机理可能是经过胰岛素、T₃、T₄等内分泌激素和生长轴介导的。更多还原

【Abstract】 The objectives of the present study were to reveal the effects of cysteamine compound on performances and endocrine hormones of lactating cow during hot summer, and look for new solution to relieve heat stress of lactating dairy cow. Series I : Effects of cysteamine compound on performances of late lactating cow during hot summer: The aim of this study was to investigate the effects of cysteamine compound (Lactonin)on milk production of late lactating cows during hot summer when the temperature humility index (THI) was higher than 76 and cows were suffered from heat stress. In this experiment 96 black and white dairy cows at late-lactation(210 d postpartum) was assigned into 4 groups (G), based on milk yield (M) prior to the experiment (Gl<24, 24<G2<28, 28<G3<32 and G4>32 kg/d). Each group was further divided into subgroups of cysteamine treatment (CSC, n= 49) and Control (n=47). In CSC of G1 the rectal temperature decreased (P<0.05)however milk yield, fat-corrected milk, milk fat and feed conversion rate (FCR) increased (P<0.05). These were companied with trendy (0.05<P<0.15) of higher milk protein and lower somatic cell count. Plasma T3,T4 tended (0.05<P<0.15) to decline whereas insulin enhanced (P<0.01) significantly in CSC herd (n=49). Series II : Effects of cysteamine compound on performances of midlactation cow during hot summer: Thirty lactating Holstein cows averaging 128 d postpartum were used to study the effect of administration(30g) cysteamine in hot weather when the temperature humility index (THI) was higher than 79 and cows were suffered from serious heat stress.The results showed that Lactonin have the same Effects on the Mid-lactation dairy cows. The above data show that Lactonin helps heat-stressed cow to maintain a more normal metabolism in hot summer. This positive effect of Lactonin on cow performance was associated with Lactonin-dependent alteration of plasma insulin, T3 and T4. The response of milk and FCM yields and apparent efficiency of production to Lactonin administration dependedon the level of production prior to treatment .Cows at low pretrement production increased milk and FCM yields to a greater degree than did cows at higher production.更多还原