Effect of addition of a progesterone intravaginal insert to a timed insemination protocol using estradiol cypionate on ovulation rate, pregnancy rate, and late embryonic loss in lactating dairy cows1

Abstract

The objectives of this study were to determine the effects of incorporating a progesterone intravaginal insert (CIDR) between the day of GnRH and PGF2alpha treatments of a timed AI protocol using estradiol cypionate (ECP) to synchronize ovulation on display of estrus, ovulation rate, pregnancy rate, and late embryonic loss in lactating cows. Holstein cows, 227 from Site 1 and 458 from Site 2, were presynchronized with two injections of PGF2alpha on study d 0 and 14, and subjected to a timed AI protocol (100 mixrog of GnRH on study d 28, 25 mg of PGF2alpha on study d 35, 1 mg of ECP on study d 36, and timed AI on study d 38) with or without a CIDR insert. Blood was collected on study d 14 and 28 for progesterone measurements to determine cyclicity. Ovaries were scanned on d 35, 37, and 42, and pregnancy diagnosed on d 65 and 79, which corresponded to 27 and 41 d after AI. Cows receiving a CIDR had similar rates of detected estrus (77.2 vs. 73.8%), ovulation (85.6 vs. 86.6%), and pregnancy at 27 (35.8 vs. 38.8%) and 41 d (29.3 vs. 32.3%) after AI, and late embryonic loss between 27 and 41 d after AI (18.3 vs. 16.8%) compared with control cows. The CIDR eliminated cows in estrus before the last PGF2alpha injection and decreased (P < 0.001) the proportion of cows bearing a corpus luteum (CL) at the last PGF2alpha injection because of less ovulation in response to the GnRH and greater spontaneous CL regression. Cyclic cows had greater (P = 0.03) pregnancy rates than anovulatory cows at 41 d after AI (33.8 vs. 20.4%) because of decreased (P = 0.06) late embryonic loss (16.0 vs. 30.3%). The ovulatory follicle was larger (P < 0.001) in cows in estrus, and a greater proportion of cows with follicles > or = 15 mm displayed estrus (P< 0.001) and ovulated (P = 0.05) compared with cows with follicles <15 mm. Pregnancy rates were greater (P < 0.001) for cows displaying estrus, which were related to the greater (P < 0.001) ovulation rate and decreased (P = 0.08) late embryonic loss for cows in estrus at AI. Cows that were cyclic and responded to the presynchronization protocol (high progesterone at GnRH and CL at PGF2alpha) had the highest pregnancy rates. Incorporation of a CIDR insert into a presynchronized timed AI protocol using ECP to induce estrus and ovulation did not improve pregnancy rates in lactating dairy cows. Improvements in pregnancy rates in cows treated with ECP to induce ovulation in a timed AI protocol are expected when more cows display estrus, thereby increasing ovulation rate.

Conception rate and estrous return detection after TAI in Holstein cows

“…According to these authors, anestrous cows had a conception rate of 29.0% (419/1445) while cyclic cows had 41.1% (1925/4679). Similar results were demonstrated by Galvão et al (2004); comparing the same TAI protocol as this trial, they found a tendency of cyclic cows to have a greater pregnancy rate than anestrous cows (40.3 vs. 29.2%). The presence of a CL and DIM did not affect estrous return detection rate after TAI in Holstein cows (Tables 3 and 4).…”

Comparison of synchronisation and fertility after different modifications of the ovsynch protocol in cyclic dairy cows

“…Brusveen et al (2009) reported similar synchronisation rates between the cows treated with and without an extra dose of PGF 2α (89% and 90%, respectively). Additionally, the synchronisation rates were not affected by CIDR administration during the Ovsynch protocol in previous studies (Kim et al, 2003;Galvao et al, 2004). Thus, it was found that a double dose of PGF 2α or CIDR administrations (6 or 7 days) had no effect on increasing the synchronisation rate during the Ovsynch protocol.…”

“…Similarly, our results showed that the response to GnRH-1 was between 55% and 64%. It is aimed to increase the ovulation rate in response to GnRH-1 in the OVS-6CIDR group by inserting a CIDR one day after GnRH-1 administration because progesterone concentrations after CIDR insertions decrease ovulation in response to GnRH administration (Galvao et al, 2004). Our results showed a numerical increase (7%) in response to GnRH-1 in the OVS-6CIDR group and that the administration of exogenous progesterone one day after GnRH-1 did not increase the response to GnRH-1 in cyclic lactating dairy cows.…”

“…For instance, administering exogenous progesterone (CIDR) between the GnRH-1 and PGF 2α treatments is a modification of the Ovsynch protocol that is reported to increase the response to GnRH-2 and may therefore improve pregnancy rate (Stevenson et al, 2006;Galvao and Santos, 2010). However, another study showed that the administration of exogenous progesterone during the Ovsynch protocol decreases the response to GnRH-1 because of the possible negative feedback effect of progesterone on LH secretion (Galvao et al, 2004). Thus, any attempt to eliminate the possible negative effect on the response to GnRH-1 during progesterone administration, based on the Ovsynch protocol, may result in a higher response to GnRH administration and a higher pregnancy rate.…”

Pharmacokinetic analysis during intravaginal progesterone-releasing devices (PRID®/CIDR®) application in the mare

“…The intra-vaginal route employs devices originally developed for the ovine and bovine industries to synchronise and/or induce oestrus (Munro 1990, Broadbent et al 1993, Uehlinger et al 1995, Galvao et al 2004, Stevenson et al 2006: sponges (Dinger et al 1981), PRID ® with oestradiol (Rutten et al 1986, Ataman et al 2000, Newcombe 2002), CIDR ® (Jöchle et al 1991, Arbeiter et al 1994, Newcombe and Wilson 1997, Handler et al 1999, Foglia et al 1999. A device developed for mares was also made available in Australia under the name of Cue-Mare ® (Grimmett et al 2002).…”