evaluation of the presence of anti zona pellucida antibodies is the serum of repeat breeder holstein dairy cattle

This study was conducted to evaluate the presence of anti zona pellucida antibodies in the serum of  repeat breeder Holstein cows in Third station Dairy Cattle Husbandry Agro Industry  in Moghan. The study was conducted on 168 non-pregnant cows with a history of Repeat breeder. Animals were selected in two age groups ¸ more than three times calving or less. Ten ml of blood were obtained from Animals from the jugular vein and serum was separated. The presence of anti-ZP antibodies in animal sera were tested by commercial test kits for ELISA (Bioserve Diagnostic, Zona pellucida antibody ELISA, BS-20-20, Germany). From a total of 168 tested animals, 13 animals tested positive (7.74%) and 155 animals were negative (92.26%). Five of 109 cattle with less than three calving were positive and 8 of 59 animals with more than three calving were positive. The results showed highly significant differences between the two groups (Z=2/07) and this means that increasing age has a significant effect on the rate of appearance of anti zona pellucida antibodies in the serum of these animals.