Improvement of reproductive performance in crossbred zebu anestrous primiparous cows by treatment with norgestomet implants or 96 h calf removal

Treatment with an intravaginal progestagen and estradiol to prevent prolonged anestrus in crossbred zebu cows under tropical conditions

“…However, they were lower than the previously reported values in this region in cows with more than 100 dpp treated with Norgestomet (Portillo et al, 1999;Soto-Belloso et al, 2002), CIDR (Soto et al, 1998) or intravaginal sponges impregnated with MAP (Perea et al, 2001).…”

Impact of Equine Chorionic Gonadotropin Associated with Temporary Weaning, Estradiol Benzoate, or Estradiol Cypionate on Timed Artificial Insemination in Primiparous Bos Indicus Cows

“…They found that P 4 + TW treatment was more effective than that in other groups, as well as TW + eCG that resulted in better PR rates (Sá Filho et al 2010). B. indicus cows treated with norgestomet + 500 IU eCG after removal of the implant, or treated only with TW (96 h) showed greater efficiency by reducing the estrus interval/first service, and increasing the conception rate (Soto Belloso et al 2002). Cows milked twice daily without calves, presented a shorter duration between parturition/first estrus and additionally showed better reproductive efficiency than cows with suckling calves.…”

“…Cows milked twice daily without calves, presented a shorter duration between parturition/first estrus and additionally showed better reproductive efficiency than cows with suckling calves. The calf suckling action activates mechanisms that inhibit the hypothalamic-pituitary-ovarian axis of the cow after delivery for longer than 90 days (Soto Belloso et al 2002). Although the mechanism of this process is not fully understood, the response of estrus depends partly on the number of follicles and their level of maturity when the calf is removed (Dunn et al1985).…”

“…To improve reproductive efficiency several protocols for TAI have been proposed, including eCG and TW. Soto Belloso et al (2002) administered P 4 plus eCG or TW to induce fertile estrus, reduce the interval between estrus, and lower birth-conception interval in anestrus B. indicus cows. Meneghetti et al (2009) conducted studies in a commercial herd aiming to develop a protocol for TAI, to reach a PR of 40% to 55% in B. indicus cows.…”

The effects of ambient temperature and humidity on pregnancy rate in Beefmaster cows in a subtropical environment of Mexico

“…In extensively managed Zebu cattle operations in tropical pastures this is not an achievable goal, due to marked variations in seasonal pasture growth and the prolonged postpartum anestrous in these cattle. Lactating Bos indicus and Bos indicus derived females usually cycle 6-7 months post-partum (Soto-Belloso, 2002), whereas other authors have reported 4.7 months for resumption of ovulation post partum in tropical composites (McGowan and Holroyd, 2008). Thus, anestrous is the main factor that negatively affects reproductive performance of beef cattle in tropical areas mainly via suckling and maternaloffspring bond and pre-and postpartum nutritional status.…”