Effect of Diatery Zinc Level on Volume and Quality of Bull Semen
2 Aksaray Üniversitesi Teknik Bilimler Meslek Yüksek Okulu, Aksaray
3 Aksaray Üniversitesi Veteriner Fakültesi Dölerme ve Suni Tohumlama Anabilim Dalı, Aksaray - The project was conducted in Livestock Central Research Institute. In the experiment 9 head Holstein bulls were used as project material. Bulls were split into groups of three heads as one control (40 mg/kg) and 2 different levels of zinc groups (150 mg/kg, group 1; 200 mg/kg, group 2) randomly by drawing of lots. Bulls in the control group were fed with compound feed containing 40 mg/kg zinc and bulls in two other treatment groups were given additional 110 mg/kg (Group1) and 160 mg/kg (Group 2) zinc respectively. As zinc preparation in control and other two treatment groups, organic zinc compound, Bioplex Zinc (zinc chelate of amino acid hydrate by Alltech) was used. After 60 days of a preliminary feeding period, semen was collected as 2 ejaculates at each time in 2 times a week during 5 weeks. After dilution and equilibration, semen was filled into straws of 0.25 mL volume and frozen by controlled freezing device and stored in liquid nitrogen. Evaluation of native semen was carried out on the same day, and of frozen semen was done after the freezing procedure of 24 hours by thawing straws in 37°C for 30 seconds.
With regard to semen volume, there were no differences between the control group and group 2 while the difference between group 1 and the control was significant (P <0.05). For motility and mass activity, differences were significant for either experimental groups (P<0.005). As for density, differences between control group and experimental groups were statistically significant and the best result was obtained from the group 1. The best result for after-thawing motility was obtained from the group 2.
As a result, it may be deduced that compound feeds contain 150 mg/kg or 200 mg/kg zinc may be better for breeding bulls than compounds containing 40 mg/kg zinc which is recommended for breeding bulls by NRC 2001, but it still requires further investigations.
Keywords : Diatery Zinc Level, Bull semen, semen quality