3Hamer J P Ⅲ, Smith J F, Brook M, et al. Sprinkler Systems for Cooling Dairy Cows at a Feed Line[M].Kansas; Kansas State University, 1999.
4Moghaddam A, Karimi I, Pooyanmehr M. Effects of short-term cooling on pregnancy rate of dairy heifers under summer heat stress [J].Veterinary Research Communications, 2009, 33: 567-575.
5李如治.家畜环境学[M].3版.北京:中国农业出版社,2003:42-43.
6Ingraham R H, Gillette D D,Wagner W D. Relation of temperature and humidity to conception rate of Holstein cows in subtropical climate[J].J Dairy Sci.,1974,57:476-481.
7McDowell R E. Improvement of livestock production in warm climates[M].USA:W.H. Freeman and Co., San Francisco,1972: 66-110.
8Bohmanova J, Misztal I, Cole J B.Temperature-Humidity Indices as Indicators of Milk Production Losses due to Heat Stress[J].J Dairy Sci, 2007,90(4):1947-1956.
