张掖地区围栏育肥牛场防风墙后不同风速对肉牛场环境及肉牛生产性能的影响

本试验旨在研究防风墙在不同遮蔽距离的减风效果以及风速对牛生产性能的影响。选取初始体重差异不显著的40头牛随机平均分布在选定的4个牛栏中,根据牛栏距防风墙的远近分为2组,测定其日增重。同时根据牛场实际条件和天气状况布置测点,对测点的风速、温度等其他环境指标和肉牛的产热进行现场实测与计算分析。结果表明:安装防风墙的围栏育肥牛场在墙后1.2 m高度,水平遮蔽距离10倍墙高的范围内,可折减风速40%～70%;防风墙后的最佳遮蔽区域是在距离防风墙2～4倍墙高处、水平遮蔽距离6倍墙高距离范围内,风速折减效果明显,最大折减率可达70%左右;肉牛平均体重为480 kg,在外部风冷指数为-15.61的条件下,安装防风墙的围栏育肥牛场的风冷指数可以降低到-9.00,每头牛每小时可减少热量损失3.31 MJ;由于距离防风墙的远近不同,肉牛日增重相差0.15 kg/(头·d),但差异不显著(P>0.05)。

Effect of Windbreak Wall in Finishing Farm on Performance of Beef Cattle in Zhangye District

This experiment focuses on the effect of windbreak wall at different levels of shelter distance and the effect of wind speed on cattle performance. According to the actual conditions and weather conditions of the fattening cattle farms,measuring points are set up to carry out on-site measurement and analysis. At the same time, the actual effect of the windbreak wall is summarized and systematically analyzed. The results showed that windbreak wall in the fattening cattle farm can reduce the wind speed by 40%～70% within a horizontal distance of 10 times of the wall height at a height of 1.2 meters.The best sheltered area behind the windbreak wall is 2 to 4 times of the height of the windbreak wall. Within the distance of 6 times of the wall height, the wind speed reduction effect is obvious and the maximum reduction rate can reach 70%. With an external WCI of-15.61 and an average beef cattle weight of 480 kg, the WCI of the fattening cattle farm equipped with a windbreak can reach-9.00, and each cow can reduce heat loss by 3.31 MJ per hour. At the same time, due to the difference in distance from the windbreak wall, the daily weight gain of beef cattle has no significant difference, which was 0.15 kg/head·day(P>0.05).