Estrus DetectionEstrusEstrus SynchronizationInsemination, ArtificialProgesteroneCattlePregnancyMelengestrol AcetateOvulationProgesterone CongenersEstrous CycleDiestrusDinoprostSexual MaturationFertilityPregnenedionesEstradiolPostpartum PeriodProestrusSwineLitter SizeGonadotropins, EquineReproductionWeaningLactationLuteinizing HormoneAdministration, IntravaginalCorpus LuteumPregnancy, AnimalDrug ImplantsTime FactorsSexual Behavior, AnimalOvaryRandom AllocationAnestrusOvarian FolliclePregnadienesPregnancy RateGonadotropin-Releasing Hormone