effects of summer and winter temperature–humidity index on performance of some reproductive traits of high producing dairy cows
نویسندگان
چکیده
the aim of this study was to consider reproductive performance parameters and blood progesterone concentration changes in high-producing dairy cows (39±2 kg per day) after artificial insemination, in summer and winter. 270 heads of holstein dairy cattle were choose in three big dairy farms, and blood samples were collected at days seven, ten and fourteen after artificial insemination. temperature-humidity index was calculated according to one proposed formula (dikmen and hansen, 2009). the results showed that the maximum temperature–humidity index(thi) was 77.35 and 57.47 in summer and winter respectively. pregnancy rates in cows inseminated during the winter months was significantly higher (p
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عنوان ژورنال:
علوم دامی ایرانجلد ۴۷، شماره ۲، صفحات ۳۲۱-۳۲۷
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