Abstract:

In this study, it was aimed to detect the effects of conventional semen, sexed-semen and embryo transfer on pregnancy rates in Holstein dairy cows. In the study, a total of 139 healthy cows with the serum progesterone > 8 ng/ml were used as animal material. Estrus synchronization protocol was applied and cows were divided into three different groups as conventional semen group (G1, n=46), sexed semen group (G2, n=47), and embryo transfer group (G3, n=46) considering age, body condition score, lactation number, and body weight. Cows in G1 and G2 were inseminated with conventional semen and sexed-semen, respectively. Embryo transfer was performed to cows in Group 3 (n=46) 7th day after estrus. The embryos were transferred to recipients as freshly. Pregnancy examinations for the cows were conducted on the 30th and 60th days of gestation. The statistical analysis of the obtained results was performed. Pregnancy rates were detected as %50, %46,8 and %69,56 in G1, G2, and G3 respectively on 30th day. On 60th day, however, pregnancy rates were %45.60, %42.55 and %67.39 in G1, G2, and G3 respectively due to embryonic losses. The pregnancy rate was significantly higher in the embryo transfer group (G3) compared to the conventional semen (G1) and sexed-semen (G2) group (p<0.05) on both 30th and 60th days. There was no significant difference between G1 and G2 (p>0.05). Findings led to the conclusion that higher serum progesterone level may increase pregnancy rate in cattle. In addition, it is evident that embryo transfer has the potential for widespread use in the field of veterinary medicine in terms of genetic progress.

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