冷、热应激对奶牛血液生理生化指标影响

以16头荷斯坦牛为实验对象，研究不同环境温度下冷应激（-30℃、-20℃、-5℃）与热应激（31℃）对奶牛的血液生理常值、生化指标的影响。研究结果表明在冷应激期：（1）白细胞、红细胞、血小板和单核细胞的变化在温差15qC尤为突出（P〈0．05）；（2）血清中Ca2＋的含量随着温度的降低而降低（P〈0．05）；（3）血清P含量无明显变化（P〉0．05），降至-30℃时血清P含量显著降低（P〈0．05）。在热应激期：白细胞、红细胞及单核细胞的变化尤为突出。（1）白细胞、红细胞数目均减少（P〈0．05）；（2）嗜碱性粒细胞、单核细胞有显著的变化（P〈0．05）。通过本次试验，在严寒和炎热环境下，采取各种有效措施缓解奶牛血液中各项指标的变化，以达到预防冷、热应激的目的，同时研究我区奶牛在冷、热刺激下的生理变化，为进一步制定缓解奶牛冷、热应激的技术措施提供理论依据。

Effect of Cold and Heat Strees on the Blood Physiological and Biochemical Indexes of Cows

In this paper, 16 Holstein cows were used to study the effects of cold stress（-30℃, -20℃, -5℃） and heat stress （31℃） on cows physiological values of the blood and biological and chemical indicators under different ambient temperature. The resuhs showed that in cold stress period：（1） white blood cells, red blood cells, platelets and changes in monocyte were particularly magnificent in 15℃（P〈0.05）;（2） serum Ca2＋ levels decreased with the temperature descent （P〈0.05）;（3） serum P concentration had no significant change（P〉0.05）, when the temperature went down to -30℃, the P concentration were significantly lower than before（P〈0.05）. In the heat stress period, the changes of white blood cells, red blood cells and mononuclear cells were particularly prominent： （1） white blood cells, red blood cells reduced（P〈0.05）; （2） basophilie cells, monocytes showed significant changes（P〈0.05）. Through this test, in the cold winter and hot summer, effective measures should be taken to protect cows from cold and heat and to alleviate cow blood changes. Meantime, we would take some time study physical changes under such extreme conditions, only in these ways, can we provide theoretical basis for drawing relevant alleviating measures to ease cold, heat stress.