@article { author = {Dirandeh, E. and Rezaei Roodbari, A. and Shohreh, B.}, title = {Effect of GnRH injection at day 6 and 12 after insemination on fertility of Holstein dairy cows during the warm season}, journal = {International Journal of Advanced Biological and Biomedical Research}, volume = {2}, number = {1}, pages = {125-131}, year = {2014}, publisher = {Sami Publishing Company}, issn = {2383-2762}, eissn = {2322-4827}, doi = {}, abstract = {The objective of this study was to determine the effects of two different time of GnRH injection after artificial insemination (A.I) (d 6 and d 12) on reproductive performances of Holstein cows during the warm season.  Cows randomly assigned to treatments 1) No GnRH injection (control, n = 300),2) GnRH injection at day 6 after A.I (G6, n=300) and 3) GnRH injection at day 12 after A.I (G12, n=300). Ultrasonography was used to detect pregnancy and late embryonic/fetal mortality between Days 32 and 60 after AI. Data were analyzed using Proc GLM of SAS. Results showed treatment affected the percentage of cows diagnosed pregnant at 32±1 d and 60±3 d after resynchronized AI. A greater percentage of G6 (25.0%) cows were pregnant at 32 d after resynchronized AI than control cows (19.3 %) and G12 cows (20.0 %). The risk of pregnancy loss between d 32 and 60 of gestation was affected by treatments and decreased in cows received GnRH injection after AI Compared to control cows. Percentage of cows that showed estrus at 19-24 d after AI was highest in G6 cows and lowest in control cows compared to other treatments. In summary, administration of a GnRH on Day 6 after AI improved reproductive performance in dairy cows.}, keywords = {GnRH,Fertility,Warm season,Holstein cows}, url = {https://www.ijabbr.com/article_7042.html}, eprint = {https://www.ijabbr.com/article_7042_a9e2e85f628ab350440af811a18b1fb4.pdf} }