Effect of progesterone, human chorionic gonadotropin and progesterone + human chorionic gonadotropin treatment on conception rates in repeat breeder cows

Hasan Alkan,Huseyin Erdem

doi:10.2754/avb202089040307

Abstract

The aim of this study was to investigate the effects of hormonal support on the pregnancy rate in repeat breeder cows. Prostaglandin F2α + Ovsynch oestrus synchronization protocol was applied to the cows. Following the fixed time insemination (day 0), the cows were divided into 4 groups. In Group 1 (n = 42), progesterone releasing intravaginal device (PRID) was placed vaginally at 84 h and removed on the 9th day after the artificial insemination. In Group 2 (n = 40), the cows were administered human chorionic gonadotropin (hCG) on the 7th day. Group 3 (n = 45) was applied a combination of progesterone and hCG. Group 4 (n = 42) was not given any treatment. Blood samples were collected from all cows 4 times on days 3.5, 7, 12, and 18 to evaluate progesterone concentrations. The pregnancy rates were 40.47%, 37.50%, 44.44%, and 30.95% in Group 1, 2, 3, and 4, respectively (P > 0.05). In addition, in cows with progesterone concentrations <2 ng/ml on day 3.5, the pregnancy rates were found to be lower than in the cows with progesterone concentrations >2 ng/ml in Group 4 (P < 0.05). Progesterone supplementation in cows with progesterone concentrations < 2 ng/ml appeared to increase pregnancy rates (P < 0.05) in Groups 1 and 3. As a result, post-insemination hormonal applications in the repeat breeder cows did not increase the pregnancy rate. However, it was concluded that determination of progesterone concentrations on day 3.5 following artificial insemination and then hormonal support in the cows with low concentrations would increased the pregnancy rate.

Highlights

The aim of this study was to investigate the effects of hormonal support on the pregnancy rate in repeat breeder cows
Progesterone regulates the degree of uterine secretions, development of the conceptus, production of interferon tau (IFN-t) by the conceptus that suppresses the luteolysis, and prostaglandin F2α (PGF2α) release (Morris and Diskin 2008)
In these studies, differences in the evaluation of the efficacy of hormonal applications may be in question since the evaluations made according to the progesterone concentration during the applications are very few in repeat breeder cows

Summary

Introduction

The aim of this study was to investigate the effects of hormonal support on the pregnancy rate in repeat breeder cows. The incidence of pregnancy loss due to fertilization failures and embryonic death at the early stages in the repeat cows was reported to be around 29–40% and 29–47%, respectively (Ayalon 1978; Diskin et al 2012). The insufficient release of progesterone leads to poor development of the embryo and to early embryonic loss (Mann and Lamming 1999) Hormones such as progesterone, gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) are widely used to increase the conception rate in cows by increasing the concentration of progesterone (BonDurant et al 1991; Khoramian et al 2011; Ergene 2012; Pandey et al 2016). The aim of this study was to investigate the effects of progesterone concentration and hormonal supplementation after AI on the pregnancy rates in the repeat breeder cows

Objectives

Methods

Results

Conclusion