Introduction Although estrous synchronization has been cited over the past several decades to have significant impact on reproductive performance of beef cattle (Schafer et al., 1990), only a limited percent of beef cattle operations in the U.S. synchronize estrus. In a summary by the National Animal Health Monitoring Systems (NAHMS) only 3.3% of beef cattle in the U.S. were being synchronized ...

The objectives were to determine the effects of insemination with sexed semen at spontaneous and induced estrus, fixed-time insemination at synchronized estrus, the deposition site, estrous intensity, housing, age, body weight, and bull on the pregnancy rate in Holstein heifers, and to compare the quality traits of sexed sperm with those of unsexed semen. The study was conducted on 3206 heifers...

Two experiments were performed to determine the effectiveness of different progestogens contained in intravaginal devices, different doses of eCG and subsequent hCG treatment on the reproductive performance of estrus-induced mature Lori ewes. In the first experiment, 88 ewes were allocated into two groups, and were treated with either fluorogestone acetate (FGA) sponges or Controlled Internal D...

Five experiments were conducted on commercial farms in Brazil designed to develop the basis for an estrus synchronization protocol using melengestrol acetate (MGA) in Bos indicus cattle. These studies resulted in the development of the following protocol: 0.5 mg x d(-1) of MGA between d -14 and -1; 2.0 mg i.m. injection of estradiol cypionate on d -9; 48 h temporary weaning between d 0 and 2; a...

The aim of this study was to investigate the period of estrus cycle in aceh cattle, Indonesia, based on vaginal cytology techniques. Four healthy females of aceh cattle with average weight of 250-300 kg, age of 5-7 years, and body condition score of 3-4 were used. All cattle were subjected to ultrasonography analysis for the occurrence of corpus luteum before being synchronized using intramuscu...

Since their reproduction is seasonal, goat lambs can not mate before the breeding season begins, even if they have reached maturity. This situation leads to economic losses for farmers. Estrus synchronization with progesterone and PMSG combination widely practiced produce off-season heat. However, different applications are made regarding dose timing of PMSG. In study, effects (500 IU) administ...

Ninety-eight Alpine goats of two herds were followed over 4 years in a program of annual artificial insemination after estrus induction/synchronization, including progestagen administration (vaginal sponge) followed by prostaglandin analog and equine chorionic gonadotrophin (eCG) 48 h before sponge removal. Goats were sampled every 4 hours from the 16th to the 56th following sponge removal, for...

This study compared the responses shown by lactating dairy cows to four different P4-based protocols for AI at estrus. Cows with no estrous signs 96 h after progesterone intravaginal device (PRID) removal were subjected to fixed-time AI (FTAI), and their data were also included in the study. In Experiment I, follicular/luteal and endometrial dynamics were assessed every 12 h from the beginning ...