Efficacy of an intravaginal progesterone insert and an injection of PGF2alpha for synchronizing estrus and shortening the interval to pregnancy in postpartum beef cows, peripubertal beef heifers, and dairy heifers.

Abstract

The objective was to test the efficacy of an intravaginal progesterone insert and injection of PGF2alpha for synchronizing estrus and shortening the interval to pregnancy in cattle. Cattle were assigned to one of three treatments before a 31-d breeding period that employed artificial insemination. Control cattle were not treated, and treated cattle were administered PGF2alpha or an intravaginal progesterone-releasing insert (CIDR) for 7 d and treated with PGF2alpha on d 6. The treatments were applied in one of three experiments that involved postpartum beef cows (Exp. 1; n = 851; 56+/-0.6 d postpartum), beef heifers (Exp. 2; n = 724; 442.5+/-2.8 d of age), and dairy heifers (Exp. 3; n = 260; 443.2+/-4.5 d of age). Luteal activity before treatment was determined for individual cattle based on blood progesterone concentrations. In Exp. 1, there was a greater incidence of estrus during the first 3 d of the breeding period in CIDR+PGF2alpha-treated cows compared with PGF2alpha-treated or control cows (15, 33, and 59% for control, PGF2alpha, and CIDR+PGF2alpha, respectively; P < 0.001). The improved estrous response led to an increase in pregnancy rate during the 3-d period (7, 22, and 36% for control, PGF2alpha, and CIDR+PGF2alpha, respectively; P < 0.001) and tended to improve pregnancy rate for the 31-d breeding period for cows treated with CIDR+PGF2alpha, (50, 55, and 58% for control, PGF2alpha, and CIDR+PGF2alpha, respectively, P = 0.10). Improvements in rates of estrus and pregnancy after CIDR+PGF2alpha, were also observed in beef heifers. Presence of luteal activity before the treatment period affected synchronization and pregnancy rates because anestrous cows (Exp. 1) or prepubertal heifers (Exp. 2) had lesser synchronization rates and pregnancy rates during the first 3 d of the breeding period as well as during the entire 31-d breeding period. The PGF2alpha, and CIDR+PGF2alpha but not the control treatments were evaluated in dairy heifers (Exp. 3). The CIDR+PGF2alpha-treated heifers had a greater incidence of estrus (84%) during the first 3 d of the breeding period compared with the PGF2alpha-treated heifers (57%), but pregnancy rates during the first 3 d or during the 31-d breeding period were not improved for CIDR+PGF2alpha compared with PGF2alpha-treated heifers. In summary, the concurrent treatment of CIDR and PGF2alpha improved synchronization rates relative to PGF2alpha alone or control. Improved estrus synchrony led to greater pregnancy rates for beef cows and beef heifers but failed to improve pregnancy rates for dairy heifers.

Taxa de prenhez em vacas mestiças submetidas ao protocolo de IATF e aplicação de análogo de GnRH 12 dias após a IA

“…Synchronization and induction of estrus are important tools in beef cow production systems, as they allow most of the herd to return to cyclicity and/or to begin a new gestation in a shorter period of time (Lucy et al 2001Borges, 2008. Baruselli et al (2004), Kasimanickam et al (2006) and Smith et al (2008) showed that hormone protocols that eliminate the need for estrus detection, thus favoring fixed-time artificial insemination (FTAI), are more attractive, however they present pregnancy rates ranging between 25 and 67%.…”

Progesterone inserts may help to improve breeding readiness in beef heifers

“…The use of progesterone to influence the onset of puberty has been widely studied (Smidt and Majerciak 1971;Wood-Follis et al 2004;Jaeger et al 1992;Lucy et al 2001;Colazo et al 2003). Progesterone-based protocols have been tested for their effectiveness in inducing puberty and synchronizing estrus.…”

“…CIDRs can reduce the time to puberty in beef heifers and effectively synchronize estrus in cattle (Lucy et al 2001;Colazo et al 2003;Chenault et al 2003). In these studies, after the CIDR implant was removed on the 7th day of treatment, a fixed-time artificial insemination was performed at the resulting estrus (Lucy et al 2001).…”

Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N’Dama cattle

“…After disinfecting the vulva region using a 5 % Ecutan® solution (chlorhexidine digluconate 50 mg/ml), a CIDR® (1.38 g of progesterone, Zoetis Belgium) was inserted for 7 days (Lucy et al 2001) PGF 2α (2 ml of Estrumate®, 250 μg/ml of cloprostenol, Intervet Belgium) was administered IM to each animal 2 days before removing the CIDR®. After CIDR® removal (day 0), animals were split into five experimental groups.…”