Abstract
Experiments were conducted to improve jenny conception rates through induced ovulation and timed insemination. Jennies in control, hCG and LH groups were injected intramuscularly with saline alone or saline containing hCG or LH, respectively, when the dominant follicle diameter reached 35 mm. Then, follicle development was checked every 8 h until the dominant follicle ovulated. While 76% of the hCG-treated jennies ovulated between 24 and 48 h, and 84% of the LH-treated ovulated between 24 and 40 h after injection, ovulations in control jennies scattered over an extended period after injection. Conception rates after insemination were significantly higher in LH- or hCG-treated jennies than in the conventionally-bred jennies. The LH preparation used in this study contained more FSH than the hCG preparation did, and supplementing the hCG treatment with FSH significantly improved ovulation synchronization. Ovulations in jennies treated on rainy days were significantly postponed and less synchronized compared to those in jennies treated on sunny days. Together, the results suggested that jenny conception could be significantly improved by inducing ovulation with LH or hCG treatment followed by timed insemination and that FSH and the weather during treatment had profound effects on ovulation induction of jennies.
Highlights
Breeding management is of great importance for the development of the donkey industry
While about 73% of the jennies treated with human chorionic gonadotropin (hCG) alone ovulated from 24 h to 48 h after injection, about 75% of the jennies treated with hCG plus FSH ovulated from 24 h to 40 h after the treatment, confirming that FSH supplementation had facilitated ovulation synchronization of jennies
Since the aim of the ovulation induction treatment is to accurately predict ovulation time, differences in ovulation synchronization among different treatments were emphasized in this study
Summary
Breeding management is of great importance for the development of the donkey industry. Several hormones have been tested to induce ovulation in equids, including human chorionic gonadotropin (hCG), crude equine gonadotropin (CEG) and gonadotropin-releasing hormone (GnRH). Among these hormones, hCG is the most commonly used[1,2,3] that produced satisfactory results[4,5]. Conception rates have seldom been observed in jennies or mares following ovulation induction treatment[11]. The objectives of this study were (a) to test whether LH could be used to replace hCG for ovulation induction in jennies; (b) to observe conception rates following ovulation induction www.nature.com/scientificreports/. Treatment of jennies; and (c) to determine the effects of the weather during the ovulation induction treatment on ovulation synchronization of jennies
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