Asian Journal of Animal and Veterinary Advances1683-99191996-3289Academic Journals Inc.10.3923/ajava.2020.60.66S. WaheebReham HarbHesham M. El-AmrawiGamal A. 22020152Background and Objective: Exogenous GnRH at the onset of estrus or at time of insemination of conventional semen improves fertility. The current study aimed at evaluating reproductive performance of nulliparous Holstein heifers after insemination with sexed semen either with or without GnRH at time of insemination compared to conventional semen. Materials and Methods: A total of 300 heifers were randomly grouped and inseminated at their first natural estrus as follow: (1) Conventional semen (n = 100): inseminated with conventional semen straws (CRV, Netherlands), (2) Sexed semen without GnRH (n = 100): inseminated with sexed semen straws (SiryX®, CRV, Netherlands), (3) Sexed semen with GnRH (n = 100): inseminated with sexed semen straws combined with administration of 10 μg of Buserelin (GnRH agonist, Receptal®) by i. m injection at time of insemination. Results: Conception rate obtained by conventional semen group was significantly higher (p<0.05) than sexed semen without GnRH group (63 vs. 49%), while it was comparable to the value obtained by sexed semen with GnRH group (54%). Number of services per conception, gestational length and incidence of dystocia showed no significant difference among heifers (p>0.05). Conclusion: Therefore, conception rate of conventional semen is superior to sexed semen, however, administration of GnRH at time of insemination of sexed semen can improve its fertility output to a similar level.]]>Johnson, L.A., J.P. Flook and H.W. Hawk,198941199203Amann, R.P.,19995214411457Ettema, J.F., S. Østergaard and M.K. Sørensen,2011518871897De Vries, A., M. Overton, J. Fetrow, K. Leslie, S. Eicker and G. Rogers,200891847856Holden, S.A. and S.T. Butler,201812s97s103Soares, J.G., C.M. Martins, N.A.T. Carvalho, A.C. Nicacio and A.L. Abreu-Silva et al.,2011Bos indicus and Bos taurus superovulated donors.]]>127148153Hermes, R., F. Göritz, W.J. Streich and T.B. Hildebrandt,2007423344Seidel, G.E. and J.L. Schenk,2007105129138Vazquez, J.M., I. Parrilla, M.A. Gil, C. Cuello and I. Caballero et al.,20084318Dejarnette, J.M., M.A. Leach, R.L. Nebel, C.E. Marshall, C.R. McCleary and J.F. Moreno,20119434773483DeJarnette, J.M., C.R. McCleary, M.A. Leach, J.F. Moreno, R.L. Nebel and C.E. Marshall,20106 sex-sorted sperm dosages on conception rates of Holstein cows and heifers.]]>9340794085Mallory, D.A., S.L. Lock, D.C. Woods, S.E. Poock and D.J. Patterson,2013Hot topic: Comparison of sex-sorted and conventional semen within a fixed-time artificial insemination protocol designed for dairy heifers.]]>96854856Sales, J.N.S., K.A.L. Neves, A.H. Souza, G.A. Crepaldi and R.V. Sala et al.,201176427435Sá Filho, M.F., H. Ayres, R.M. Ferreira, M. Nichi, M. Fosado, E.P. Campos Filho and P.S. Baruselli,20107416361642Funston, R.N. and T.L. Meyer,201228560563Kaim, M., A. Bloch, D. Wolfenson, R. Braw-Tal, M. Rosenberg, H. Voet and Y. Folman,20038620122021Morgan, W.F. and I.J. Lean,199370205209Arthur, G.H., D.E. Noakes, H. Pearson and T.J. Parkinson,20012001pp: 383-473pp: 383-473Machado, V.S., R.C. Neves, F.S. Lima and R.C. Bicalho,2017938492SAS,2002Version 9.1,Chebel, R.C., F.S. Guagnini, J.E.P. Santos, J.P. Fetrow and J.R. Lima,20109324962507Norman, H.D., J.L. Hutchison and R.H. Miller,20109338803890Cerchiaro, I., M. Cassandro, R. Dal-Zotto, P. Carnier and L. Gallo,20079025382542Bodmer, M., F. Janett, M. Hässig, N. den Daas, P. Reichert and R. Thun,20056416471655Healy, A.A., J.K. House and P.C. Thomson,20139619051914Walker, W.L., R.L. Nebel and M.L. McGilliard,19967915551561DeJarnette, J.M., R.L. Nebel and C.E. Marshall,2009714958Seidel, G.E.,200359585598McCullock, K., D.L.K. Hoag, J. Parsons, M. Lacy, G.E. Seidel and W. Wailes,20139663666377Hinde, K., A.J. Carpenter, J.S. Clay and B.J. Bradford,20142014