Different protocols using PGF2α as ovulation inducer in Nelore cows subjected to estradiol-progesterone timed AI based protocols

Abstract

The objective of this study was to evaluate the effect of a PGFα-analogue (PGF) on ovulation and pregnancy rates after timed artificial insemination (TAI) in cattle. In Experiment 1 cows received an intravaginal progesterone-releasing device (CIDR) plus 2 mg im of estradiol benzoate (EB) on Day 0. The CIDR devices were removed on Day 8, and all cows received 150 μg im of d-cloprostenol (PGFα-analogue), 300 IU of eCG and 1 mg of estradiol cypionate (ECP) im. On Day 9, cows were randomly assigned into two groups: 1) ECP Group (n = 17), that did not receive any further treatment; and 2) ECP-PG Group (n = 14) that were given 150 μg of d-cloprostenol (PGF) as adjuvant stimulus for ovulation. No difference between groups was detected in interval for ovulation (P = 0.5), and in the proportion of cows ovulating (P = 0.09). In Experiment 2, multiparous suckling crossbred Aberdeen Angus cows (n = 260), were treated into two groups, similarly as Experiment 1; ECP group (n = 122), and ECP-PG group (n = 138). All females were TAI on Day 10. The proportion of cows treated with ECP that became pregnant was 54.9% (67/122), and cows treated with ECP plus PGF was 55.1% (76/138; P = 0.9). In Experiment 3, 686 Nelore cows, 40 to 50 days postpartum, were treated as Experiment 1 (ECP group), however, on Day 8 cows were divided into 3 groups: ECP Group (n = 216); PGF-SC Group (n = 228), in which cows did not receive ECP and were given an additional subcutaneous injection of PGF on Day 8; and PGF-IM Group (n = 242), in which cows also did not receive ECP on Day 8 and were given an additional injection of PGF im on Day 9. On Day 10, estrus was evaluated at timed AI (TAI). There was no difference in the diameter of the dominant follicle at CIDR removal and at TAI, and pregnancy per AI among groups (P > 0.05). However, the proportion of cows that displayed estrus between CIDR removal and TAI was higher in ECP group than in PGF-SC and PGF-IM groups (P < 0.001). Cows that displayed estrus has higher P/AI than cows that did not (P = 0.008). In conclusion, these results suggested that intramuscular or subcutaneous injection of PGFα could be successfully used to induce ovulation in cattle undergoing TAI, with similar pregnancy rates when compared with ECP. The subcutaneous injection of PGF on the same day of CIDR removal could be an interesting alternative due it reduces cattle management to obtain similar results.

Application of Embryo Transfer Technology to Improve Fertility Using GnRH Plus Progesterone and Estradiol Combination (FTAI) of Local South Pesisir Cow in West Sumatra

“…In addition, strategies established to manipulate follicular wave dynamics can optimize the efficiency of embryo production techniques. The diameter size of ovulating follicle in this present study is smaller than in crossbred cows was 13.6 ±0.5 mm in ECP protocol and 13.5± 0.7 mm [15], was 13 mm [2]. However this study is similar to [16] that diameter size of ovulating follicle range from ≤6mm to ≥ 9 mm with mean is 13.1±0.26 mm in the GnRH-FSH analogue, 8.2 ±1.16 mm in the hMG, and 4.2±1.07 mm in the eCG-FSH.…”

Prostaglandin F2? as ovulatory stimulus in dairy cows and buffaloes raised in the Amazon biome

“…Although the number of animals included in the present study is low, these evidences lead us to infer that PGF has no ovulatory effect in buffaloes. Previous studies have indicated that d-cloprostenol has an ovulatory effect similar to that of EB in TAI protocols, resulting in similar ovulation and pregnancy rates in dairy (Pfeifer et al, 2016;Castro et al, 2018) and beef cows (Pfeifer et al, 2014(Pfeifer et al, , 2018. Moreover, the injection of PGF has also been reported to act as an ovulatory stimulus in prepubertal heifers (Pfeifer et al, 2009;Leonardi et al, 2012).…”

role of prostaglandin F2α on ovulation and LH release in cows

“…Thus, understanding the role of PGF in ovulation is essential for the development of more efficient techniques and methods for the control of reproductive cycles in cows. In this sense, it is known that administration of commercial analogs of PGF results in ovulation in sheep (Davies et al, 2006) and cattle exposed to different ovulation synchronization protocols (Pfeifer et al, 2014;Pfeifer et al, 2016;Pfeifer et al, 2018;Castro et al, 2017). Additionally, the effect of PGF on ovulation is independent of its luteolytic action, since it is also able to induce ovulation in prepubertal heifers (Leonardi et al, 2012).…”

“…However, PGF is also able to hasten and synchronize ovulation in cattle (Pfeifer et al, 2014;Pfeifer et al, 2016;Castro et al, 2017) independent of its luteolytic action (Leonardi et al, 2012). Previously, we observed that d-Cloprostenol (PGF analog) had a similar ovulatory effect to that of estradiol benzoate in timed artificial insemination (TAI) protocols, resulting in similar ovulation and pregnancy rates in dairy (Pfeifer et al, 2016;Castro et al, 2017) and beef cows (Pfeifer et al, 2014;Pfeifer et al, 2018). Despite this, the mechanism of action for injectable PGF to induce ovulation in cattle is still unknown.…”