Intravaginal Device-Type and Treatment-Length for Ovine Estrus Synchronization Modify Vaginal Mucus and Microbiota and Affect Fertility.

Paula Martinez-Ros,Maria López-Mendoza,Fernando Hernandez,Marta Lozano,Alejandra Tirado,Antonio Gonzalez-Bulnes,Alejandro Rios-Abellan

doi:10.3390/ani8120226

Paula Martinez-Ros, Maria López-Mendoza + Show 5 more

Open Access

https://doi.org/10.3390/ani8120226

Copy DOI

Abstract

Simple SummaryThis study examined the effects of different intravaginal device types used for estrous cycle management in sheep, and the timing of their insertion, on vaginal features (characteristics of vaginal mucus discharge, pH and microbiota) and fertility under field conditions.Induction and synchronization of estrus and ovulation in sheep is based on intravaginal progestagen-impregnated polyurethane sponges or progesterone-loaded silicon-based devices (CIDR), in either short- (6–7 days) or long-term (12–14 days) protocols. Bearing in mind that the use of intravaginal sponges in long-term protocols has been related to the presence of vaginitis at removal, we compared the effects of sponges and CIDRs, maintained during either 7 or 14 days, on vaginal features (characteristics of vaginal mucus discharge, pH and microbiota) and fertility under field conditions. Almost all the ewes treated with intravaginal sponges showed vaginal discharge at device withdrawal, which was purulent and/or bloody in around 15% and 80% of the females treated for 7 and 14 days, respectively. The vaginal pH and microbiota changed in both groups when compared to control sheep, especially in ewes treated for 14 days, which showed a pH value around 8 and a higher incidence of Salmonella spp. and Staphylococcus aureus. On the other hand, independently of the length of the treatment, only around 15–20% of the sheep treated with CIDRs evidenced vaginal discharge (p < 0.00005 when compared to sponge groups), and such discharge was scarce, clear, and showed no changes in vaginal pH and microbiota when compared to control sheep. Fertility yields were associated with vaginal features, being higher in both short-term treatments (75%) and the long-term CIDR-based treatment (70%) than in the long-term sponge-based treatment (45%).

Highlights

Induction and synchronization of estrus and ovulation for reproductive management of sheep are traditionally based on the intravaginal insertion of progestagen-impregnated polyurethane sponges for 12–14 days, followed by the intramuscular injection of equine chorionic gonadotrophin at sponge removal [1]
The results of the present study indicate that both the type of intravaginal device and the duration of the progestative treatment (14 or 7 days) may affect characteristics of vaginal mucus discharge, pH and bacteriology, and fertility
Almost all the ewes treated with intravaginal sponges showed vaginal discharge at device withdrawal

Summary

Introduction

Induction and synchronization of estrus and ovulation for reproductive management of sheep are traditionally based on the intravaginal insertion of progestagen-impregnated polyurethane sponges for 12–14 days, followed by the intramuscular injection of equine chorionic gonadotrophin (eCG) at sponge removal [1]. The causes may be mainly related to a physical effect causing a constant retention of the vaginal secretions when intravaginal sponges are maintained for long periods of time [3], which may create a predisposition to proliferation and changes in the composition of the local microbiota [4,5]. These changes in the vaginal microbiota induce inflammation and infection associated with abnormal discharges [6]. A possible alternative for minimizing the physical effects of the intravaginal sponge is the use of a different intravaginal device, named CIDR® (Controlled Internal Drug Releasing device, Pfizer Inc., New York, NY, USA), which has been recently authorized for commercialization in the European Union

Methods

Results

Discussion

Conclusion