The Impact of Different Estrus Synchronization Programs on Postpartum Holstein Dairy Cow Reproductive Performance

Abstract

The purpose of this study was to see how the Ovsynch, modified Ovsynch, presynch, and modified presynch protocols affected postpartum reproductive performance in dairy cows. Design: Randomized controlled experimental study Animals: The current research involved 412 dairy cows. Procedures: The cows were split into four groups: GnRH was given on day 0, PGF2∝ on day 7, and GnRH on day 9. Group 1: (Ovsynch protocol, n= 117) received GnRH on day 0 and PGF2∝ on day 7. Group 2 (modified Ovsynch, n=113): PMSG on day 0, PGF2 on day 7, and PMSG on day 9. Group 3 (presynch protocol, n=98) got two doses of PGF2 14 days apart, which allowed for a 12-day delay in the start of Ovsynch. Group 4 (modified presynch protocol, n=84) got two PGF2∝ doses 14 days apart, which was 12 days before the start of modified Ovsynch. All of the animals were artificially inseminated 16 hours following their last GnRH or PMSG dose. The ovarian rebound, number of services per conception, days open, and calving interval were the measures for determining reproductive performance for the dairy cows. Results:The main effect of the synchronisation program showed no significance for ovarian rebound (P >0.05). The S/C, days open and calving intervals were decreased significantly (P＜0.05) in the 3rd and 4th groups when compared with the cows that received either GPG or PMSG treatment only. All four groups had a conception rate of 35.04 (41/117), 40.7 (46/113), 44.8 (44/98), and 57.14 (48/84) %, respectively (P＜0.05). Conclusion and clinical relevance:It was investigated that giving two PGF2 injections before Ovsynch, either utilizing GnRH or PMSG methods, improved the reproductive performance of dairy cows. Furthermore, cows given PMSG had a greater conception rate than cows given GnRH.

Effect of Gonadotrophin Releasing Hormone on Follicular Dynamics, Luteinising Hormone, and Progesterone Levels in Bunaji Cows

“…This finding agrees with an earlier report by Ahmadzaden et al, 2007 (2007), and Yamada et al (2002) who reported ovulation rates of 81% to 100% after the second GnRH treatment with the full and half-full doses of GnRH. Environmental conditions, nutritional status, and source of GnRH and PGF2 have been reported to affect reproductive outcomes following ovsynch protocol in dairy cows (Hussien et al, 2021). The treatment of Bunaji cows with the 50 g and 100 g GnRH agonist on day 0 and day 9 was able to elicit sufficient LH and P4 responses to ensure that the dominant follicle in most of the cows disappeared and new follicular wave development is initiated.…”

“…Gonadotrophin releasing hormone (GnRH) stimulates the production and release of follicle stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. The main indicators of the efficacy of treatment with GnRH include improved LH secretion, dominant follicle disappearance, and formation of a new corpus luteum (Hussien et al, 2021). The size and functional status of the dominant follicle and oestrus cycle phase may also affect the responses to GnRH treatment (Atkins et al, 2008;Colazo et al, 2008).…”

“…The procedure consists of two injections of GnRH 9 days apart and administration of PGF2 48 h prior to the second GnRH injection. The first injection of GnRH is given at a random stage of the oestrous cycle which causes ovulation or luteinization of the dominant follicle in most animals (Hussien et al, 2021). The reason for the second GnRH treatment two days after the PGF2 is to push back the timing of the LH surge and to synchronise ovulation such that single insemination is enough to ensure fertility (Atanasov et al, 2021;Randi et al, 2021;Pursely et al, 1995).…”