E STRUS and ovulation in gilts have been successfully inhibited by daily injections of progesterone (Ulberg et al., 1951; Baker et al., 1954) and more recently by the inclusion of progestational compounds in the feed (Nellor, 1960; Dzuik and Baker, 1962). The successful use of orally active progestational agents to synchronize the estrous cycles of gilts without a subsequent reduction in fertil...

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 ...

Estrous synchronization and artificial insemination (AI) are reproductive management tools available to beef producers for over 30 years. Synchronization of the estrous cycle has the potential to shorten the calving season, increase calf uniformity, and enhance the possibilities for utilizing AI. Artificial insemination allows producers the opportunity to infuse superior genetics into their ope...

Estrous synchronization and artificial insemination (AI) are reproductive management tools that have been available to beef producers for over 30 years. Synchronization of the estrous cycle has the potential to shorten the calving season, increase calf uniformity, and enhance the possibilities for utilizing AI. Artificial insemination allows producers the opportunity to infuse superior genetics...

Introduction Estrous synchronization and artificial insemination (AI) are reproductive management tools that have been available to beef producers for over 40 years. Synchronization of the estrous cycle has the potential to shorten the calving season, increase calf uniformity, and enhance the possibilities for utilizing AI. Artificial insemination allows producers the opportunity to infuse supe...

47 NC and AC1 treatments (P<0.05). N digestibility was higher in both PC and AC3 treatments compared with NC and AC1 treatments (P<0.05). The RBC count was increased in ALA treatment compared with NC treatments (P<0.05). Hemoglobin in AC2 treatment was higher than NC treatment (P<0.05). Lymphocyte, WBC, IgG and total iron binding capacity were not affected among all treatments (P<0.05). The red...

The objective of this study was to determine if factors associated with the biostimulatory effect of bulls alter breeding performance of primiparous, suckled beef cows using a progestin-based estrous synchronization protocol. We tested the hypotheses that the estrous synchronization response and AI pregnancy rates differ among cows exposed to bulls, continuously exposed to bull urine, and expos...

Traditional methods of estrus synchronization developed over the past 60 yr have involved controlling bovine estrous cycle length by administering a progestin and/or regressing the corpus luteum with luteolytic drugs. The synchrony of estrus and timing of ovulation following traditional estrus synchronization treatments has been too variable to allow the transfer of a fresh or frozen/thawed emb...