Effect of temperature-humidity index on productive and reproductive performances of Iranian Holstein cows
Effect of temperature-humidity index on productive and reproductive performances of Iranian Holstein cows
复制标题
温湿度指数对伊朗荷斯坦奶牛生产和繁殖性能的影响
DOI：
10.22099/ijvr.2013.1583
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
N. Azad
中科院分区：
文献类型：
--
作者：
N. Zadeh;A. Mohit;N. Azad
从1996年4月至2005年12月的产犊记录，包括31863产犊事件的1173头奶牛在一个大型的商业奶牛群被用来评估热应激的影响，使用温度-湿度指数（THI）的牛奶产量和组成和繁殖性能的荷斯坦奶牛在伊朗的拉什特潮湿的气候条件下。THI值分为6组：30-40（THI 1）、41-50（THI 2）、51-60（THI 3）、61-70（THI 4）、71-80（THI 5）和81-90（THI 6）。THI 6组奶牛产奶量和产脂量均低于THI其它组，但THI 1组和THI 2组奶牛产奶量和产脂量分别最高（P<0.05）。但THI第二组奶牛的乳脂率显著低于THI第六组（P<0.05）。春季产犊母牛的开口日显著长于其他季节产犊母牛（P<0.05）。夏季产犊母牛的平均受胎次数显著高于其他季节产犊母牛，受胎率显著低于其他季节产犊母牛（P<0.05）。2004-2005年春季和/或产犊年产犊的THI 5以内奶牛开口日数最长（P<0.05）。第二组THI组的受胎数和受胎率分别最高和最低。本研究结果表明，夏季热应激对奶牛的产奶量、乳成分和繁殖性能产生负面影响。因此，管理干预措施的应用，以改善热负荷对奶牛生产性能的影响，可能需要在一年中的某些时期的气候条件下。
Calving records from April 1996 to December 2005 comprising 31863 calving events of 1173 dairy cows in a large commercial dairy herd were used to evaluate the effects of heat stress, using temperature-humidity index (THI) on milk yield and composition and reproductive performance of Holstein dairy cows under humid climatic conditions of Rasht in Iran. THI values were grouped into six groups: 30-40 (THI1), 41-50 (THI2), 51-60 (THI3), 61-70 (THI4), 71-80 (THI5) and 81-90 (THI6). Dairy cows in THI6 had lower milk and fat yields than other groups of THI, but cows in THI1 and THI2 had the greatest amounts of milk and fat yields, respectively (P<0.05). However, dairy cows in the second group of THI had lower percentages of fat than the sixth group of THI (P<0.05). Spring-calved cows had longer days open than cows calved in other seasons (P<0.05). Also, summer-calved cows had greater number of services per conception and lower conception rates than cows calved in other seasons (P<0.05). Dairy cows within the THI5 which calved in spring and/or calving years 2004-2005 had the longest days open (P<0.05). Cows in the second group of THI had the greatest and the lowest number of inseminations and conception rates compared with other groups of THI, respectively. The results of the present study indicated that summer heat stress negatively affected milk yield and composition and reproductive performance of dairy cows. Therefore, application of management interventions to ameliorate the effects of heat load on the performance of dairy cows could be needed in certain periods of the year under the climatic conditions.