Ataman, Mehmet B.Erdem, HuseyinBulbul, BulentUmutlu, SeyitColak, Mehmet2020-03-262020-03-2620110001-7213https://dx.doi.org/10.2754/avb201180020171https://hdl.handle.net/20.500.12395/26897The aim of this study was to evaluate the effect of buserelin injection on day 12 postinsemination on fertility in lactating dairy cattle. A total of 57 cows were assigned to two groups and four subgroups. In the treatment group, the cows were synchronized with PGF(2 alpha)-PGF(2 alpha) (group A) or GnRH-PGF(2 alpha) (group B) protocol, and buserelin was injected on day 12 postinsemination. Cows in the control group were synchronized with PGF(2 alpha)-PGF(2 alpha) (group C) or GnRH-PGF(2 alpha) (group D) protocol, saline solution was injected on day 12, and served as controls. Pregnancy rates on day 21 and 45 and embryonic death rates were 85.7%, 71.4% and 16.7%, 85.7%, 85.7% and 0.0%, 73.3%, 62.1% and 27.3% and 85.7%, 71.4% and 16.7% in groups A, B, C and D, respectively. There was no significant difference between synchronization protocols for pregnancy rates, and among groups A, B, C and D for pregnancy rates and embryonic death rates. Mean progesterone concentrations in pregnant cows in groups A and B were higher than that in groups C and D, respectively, on day 18 and 21 (p < 0.05). In conclusion, GnRH injection on day 12 postinsemination increased the plasma progesterone concentrations on day 18 and 21 postinsemination. However, it did not alter the pregnancy rates and prevent embryonic deaths.en10.2754/avb201180020171info:eu-repo/semantics/openAccessGnRHplasma progesteronepregnancyembryonic deathcowArticle802171177Q3WOS:000293898400006Q3