02714naa a2200289 a 450000100080000000500110000800800410001902200140006002400430007410000170011724501660013426000090030050001430030952016360045265300130208865300110210165300130211265300140212565300310213965300200217070000180219070000230220870000150223170000200224670000210226677301370228710625082021-11-01       2021    bl uuuu     u00u1 u    #d  a0378-43207 a10.1016/j.anireprosci.2021.1068392DOI1 aMENCHACA, A.  aEstradiol cypionate treatment in suckling/weaning and estrous cycling/anestrous beef cows subjected to fixed-time artificial insemination.h[electronic resource]  c2021  aArticle history: Received 5 May 2021; Received in revised form 26 August 2021; Accepted 27 August 2021; Available online 3 September 2021.  aABSTRACT - This study was conducted to evaluate the interaction between dose of estradiol cypionate (ECP) and ovarian status in beef cows on which different weaning/suckling regimens were imposed before fixed-time artificial insemination (FTAI). A total of 8070 estrous cycling and anestrous cows were subjected to three experiments, when calves were weaned early (Experiment 1), anti-suckling nose plates were applied for 9 or 10 days (Experiment 2), or there was continued suckling (Experiment 3). The cows were administered an estradiol/progesterone?based treatment regimen for FTAI and were treated with 0.5 or 1.0 mg of ECP im at the time of progesterone intravaginal device removal. Artificial insemination was performed from 46 to 56 h after the time of ECP treatment. Pregnancy per artificial insemination (P/AI) was affected by dose of ECP differentially in early-weaned and suckled cows. Whereas P/AI percentage was greater in early-weaned cows treated with 0.5 than 1.0 mg ECP (P < 0.05), P/AI percentage was greater for suckled cows treated with 1.0 than 0.5 mg ECP (P < 0.05). Although there were greater P/AI percentages in estrous cycling than anestrous cows (P < 0.05) when there was nose plate weaning and continuation of suckling, there was no difference between estrous cycling and anestrous cows (P = NS) when there was early weaning. Overall results indicate ECP administration affects fertility in a dose-dependent manner, suggesting an interaction between suckling and estrous cycling effects. As more critical the condition was (i.e., suckling anestrous cows), larger dose of estradiol was required. © 2021  aEstrogen  aEstrus  aFollicle  aOvulation  aPLATAFORMA DE SALUD ANIMAL  aSynchronization1 aBOSOLASCO, D.1 aNÚÑEZ-OLIVERA R.1 aCUADRO, F.1 aSPECIALE C.J.M.1 aPEREZ-WALLACE S.  tAnimal Reproduction Science, October 2021, Volume 233, Article number 106839. Doi: https://doi.org/10.1016/j.anireprosci.2021.106839