Prostaglandin F2α or estradiol benzoate to induce ovulation in timed artificially inseminated dairy cows

Luiz Francisco Machado Pfeifer,Eduardo Kenji Nunes Arashiro,João Henrique Moreira Viana,Natália Ávila De Castro,Luiz Gustavo Bruno Siqueira

doi:10.1590/s0100-204x2016000600005

Abstract

Abstract: The objective of this work was to compare two types of ovulation inducers - estradiol benzoate (EB group) or prostaglandin F2α (PG group) -, in postpartum dairy cows subjected to timed artificial insemination (TAI). Lactating Holstein-Gir crossbred cows (n=118) with 60 to 120 days of milk production were used in this study. All cows were treated with an intravaginal progesterone-releasing device (CIDR) plus 2 mg of estradiol benzoate (EB) on day 0. The CIDR inserts were removed on day 9, and all cows received 500 µg sodium cloprostenol. Twenty-four hours after CIDR removal, cows were randomly assigned into two treatment groups and were given either 1 mg of EB i.m. (EB group) or 500 µg sodium cloprostenol i.m. (PG group). TAI were performed at 52 to 54 hours, in both EB and PG groups, after CIDR removal. No differences were observed in the ovulation (85.2% vs 72.7%) and pregnancy rates (40.7% vs 38.2%) between the EB and PG groups, respectively. Fertility is similar in the TAI protocols that use prostaglandin F2α or EB to induce ovulation in lactating dairy cows.

Highlights

Poor reproductive performance in dairy cows continues to be an important issue in the dairy industry (Lucy, 2001; Walsh et al, 2011)
Ovulation ranges from com um implante intravaginal liberador de progesterona (CIDR) removal were 66 to 78, 66 to 120, and 66 to 144 hours for estradiol benzoate (EB), PG, and Control group (CTL) groups, respectively (Table 1)
One cow was discharged from the subset of the PG group due to the lack of regression of the previous corpus luteum (CL), as confirmed by colour Doppler, and the remaining nine cows ovulated within 6 days after CIDR removal

Summary

Introduction

Poor reproductive performance in dairy cows continues to be an important issue in the dairy industry (Lucy, 2001; Walsh et al, 2011). The intensive use of timed artificial insemination (TAI) protocols, observed in commercial herds in the last two decades, has apparently stabilized the fertility in high‐yielding dairy cows. The advent of protocols for ovulation synchronization, which enables artificial insemination at a pre‐established time with adequate fertility, has become an important component of breeding management in multiple production systems (Bisinotto et al, 2014). By controlling both luteal and follicular function by exogenous treatments, it is possible to synchronize the time of ovulation and, perform artificial insemination (AI) without the need for estrus detection (Bó et al, 2002).

Objectives

Methods

Results