Effect of exogenous progesterone on superovulatory response in heifers inseminated with fresh or frozen semen

Abstract

Superovulation in cattle normally involves the administration of gonadotrophins at specific times of the oestrous cycle, followed by the induction of luteolysis and insemination with high quality semen. The first aim of this experiment was to examine the effect of supplementary progesterone when used in conjunction with porcine FSH (pFSH) to induce superovulation in heifers. The methods compared were PGF2 alpha given at mid-cycle or a progesterone-releasing intravaginal device (PRID) inserted at different phases of the cycle. The second aim was to determine whether site of insemination or use of fresh or frozen semen affected embryo production. A factorial design was used involving 185 beef heifers. The main factors were (i) synchronization methods (PGF2 alpha or PRID); (ii) semen type (fresh or frozen); (iii) insemination regimens (involving two inseminations and variations in the sites) and number of straws used (one or two) at the second insemination. Eight injections of pFSH were given twice a day for 4 days starting either on days 9, 10 or 11 of the oestrous cycle or on the fourth day after insertion of a PRID. Heifers were checked for oestrus, inseminated twice and embryos were recovered on day 7 of the superovulated cycle. There was no difference between heifers given either PRID or PGF2 alpha in the oestrous response (93% versus 96%), number of ovulations (15.9 +/- 1.11 versus 13.4 +/- 1.06), large follicles (2.5 +/- 0.24 versus 2.3 +/- 0.23) or embryos recovered (9.1 +/- 0.77 versus 9.1 +/- 0.74).(ABSTRACT TRUNCATED AT 250 WORDS)

The results of consecutive superovulations in cows by induction with various exogenous progesterone routes

“…However, exogenous progesterone application for such programs may have negative effects on high quality embryo yield (1). Goulding et al (14) emphasized that superovulation can alter the number of recovered embryo quality by exogenous progesterone treatment. There are many factors involved in the superovulatory process in cows.…”

The Response of Donor Holstein Cows to Ovarian Super-Stimulation Using Two Different Protocols GnRH and Estradiol

“…Collectively, these results suggest that the administration of exogenous FSH might not only induce growth of healthy follicles but also those that have already undergone atresia. According to Goulding et al (1994), superstimulatory treatment early in the luteal phase in heifers with a progestin device resulted in poor embryo quality which was apparently because of the stimulation of subordinate follicles that were already undergoing atresia, with oocytes that were undergoing degeneration. Hence, estradiol and progestin treatments not only eliminated the need for estrus synchronization and detection before super-stimulation, but also tended to improve ova/embryo quality.…”

Follicle Ablation Improves the Ovarian Response and the Number of Collected Embryos in Superovulated Cows During the Early Stages of Lactation

“…Goulding et al. (1994) reported that the quality of collected embryos was greatly influenced by the time of PRID insertion.…”

“…1994) and thus, after withdrawal of the implant, a new follicular wave develops. In this case, the functional dominant follicle suppresses the development of the subordinates and hence induces varying degree of degeneration to the contained oocyte; a common sequel of this is the compromised quality of yielded embryos (Goulding et al. 1994).…”