Relationship of Luteinizing Hormone Concentration with Reproductive and Productive Performance in Holstein Cows Bred in Iraq

Abstract

This research briefly reviews the effect of Luteinizing hormone (LH) on the reproductive and productive performance of German Holstein cows bred in Iraq. Blood samples were collected for 100 cows to measure the concentration of  LH  in August 2019.Cows so. The reproductive characteristics included the following:  the number of services per conception (SPC), Day opens (DO), Calving interval (CI), the rate of abortion for reproductive reasons (AB), and the Age at the first calving (AFC). Also, Its effect on milk production, which is determined by milk yield characteristics, Total milk yields (TMY), daily milk yields (DMY), and Length lactation (LL).An increase in the concentration of LH positively affected cows fertility, as (UP) cows needed  SPC 0.11 ± 1.37 service less compared to (IN) and (LO) cows which needed 3.17 ± 0.34 and 4.12 ± 0.30 service respectively, also achieved a shorter (UP) The DO duration was 149.71 ± 4.88 days which outperformed (IN) and (LO) which had 155.32 ± 3.35 days, respectively. (UP) achieved the shortest CI 457.39 ± 14.08 days. (UP) was characterized by having less AB 2.05 ± 0.19%. The (UP) achieved the youngest age at first birth 34.31 ± 0.39 months compared to (IN) and (LO) which were 35.10 ± 0.50 and 36.24 ± 0.75 months, respectively. The increased LH concentration positively affected DMY and (TMY) as UP outperformed IN and LO and negatively in (LL)  as (LO) overtook (UP).