Reproductive performance improvement in primiparous lactating Holstein cows by different hormonal treatments

This study was aimed to evaluate different hormonal treatments during early postpartum period on reproductive efficiency on 42 primiparous Holstein cows in the experimental farm of college of Agriculture, University of Baghdad, aged 3-3.2 y. during the period from 2010-2012. These cows were divided randomly into four groups according to hormonal treatment at day 50 postpartum. The 1 st group included 11 cows and was injected with GnRH 0.0126mg/IM, the 2 nd group (10 cows) injected with eCG 1000 IU/IM, the 3 rd group (11 cows) administrated by hCG 1500 IU/IM and the 4 th group (10 cows) without treatment as a control group. The results of this study revealed that the responsive cows (estrus behaviors) were 10 (90.9%), 8 (80%), 9 (81.8%) and 9 (90%) in the 1 st , 2 nd , 3 rd and 4 th group respectively and these results were recorded superior significant (P<0.01) for group 2 compared with group 1 and 3 related with duration from initiation of estrus, but no significant differences (P<0.01) between all groups about services per conception and number of conceived animal while the days open and calving interval was recorded significant differences (P<0.01) between the 1 st , 2 nd and 3 rd groups compared with control group (4 th