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Effects Of Administering Progesterone And Gnrh Before Puberty On Age At Puberty And Reproductive Response In Crossbred Beef Heifers, H.L. Miller, J.J. Wagner, R. Hanson
Effects Of Administering Progesterone And Gnrh Before Puberty On Age At Puberty And Reproductive Response In Crossbred Beef Heifers, H.L. Miller, J.J. Wagner, R. Hanson
South Dakota Beef Report, 1988
One hundred six crossbred heifers were utilized to determine prepubertal treatment of progesterone or progesterone plus Gonadotropin Releasing Hormone (GnRH) on age at puberty, conception to a synchronized estrus and conception during the breeding season. Days to puberty were 369.5 ± 6.2, 363.1 ± 9.9 and 360.4 ± 7.8 or control, progesterone primed and progesterone plus Gonadotropin Releasing Hormone (GnRH), respectively. There was no difference (P>.05) in age of puberty, number cycling before synchronization or conception rate during a 35-day breeding season. The percentage of heifers conceiving to synchronized estrus was lower (P<.10) for control compared to progesterone or progesterone plus GnRH treated heifers. Injecting GnRH at breeding had little (P>.05) effect on increasing conception rates …
Effects Of Bull Exposure And Gonadotropin Releasing Hormone On Postpartum Interval And Fertility In Beef Cowsa, H.L. Miller, R.H. Haigh
Effects Of Bull Exposure And Gonadotropin Releasing Hormone On Postpartum Interval And Fertility In Beef Cowsa, H.L. Miller, R.H. Haigh
South Dakota Beef Report, 1988
Spring calving beef cows were utilized in a study to determine the effects of bull exposure (BE) and Gonadotropin Releasing Hormone (GnRH) administration on return to estrus and reproductive efficiency. Cows were either exposed to an epididectomized bull soon after calving until the breeding season or not exposed to bulls (NE). All cows were synchronized with Synchro-Mate B (SMB). One-half of the BE and NE cows were implanted with GnRH at SMB implant removal in 1987 or given an injection of GnRH at breeding in 1988. Each year, 20 cows were bled hourly for 80 consecutive hours after SMB removal. …