Fertility of young mares after long-term anabolic steroid treatment.

This research investigates the impact of long-term anabolic steroid treatment on fertility in young mares. The study found that the fertility of the mares was negatively impacted by this treatment, with fewer mares displaying estrous behavior, shortened estrus duration, and decreased first-cycle pregnancy rates, among other findings.

Overview of the Research

• This study was conducted on 46 three-year-old mares, which had previously been treated with anabolic steroids over a period of 54 weeks. The mares received the injections every three weeks, with treatments including 1.1 mg of boldenone undecylenate (BU) per kg of body weight, 4.4 mg of BU per kg, 1.1 mg of nandrolone decanoate (ND) per kg, and 0.04 ml of sesame oil per kg as a control.
• The research aimed to investigate the reproductive behaviors and capabilities influenced by anabolic steroid use among mares. These included tracking the display of estrous behavior, the duration of estrus, the persistence of abnormal sexual behavior post-treatment, the timeline to ovulation, and conditions of the ovarian components and tubular genitalia.

Key Findings

• The study revealed a decline in the display of estrous behavior among all the groups of mares previously treated with anabolic steroids, compared to the control group. Similarly, the mares that had received steroids had a reduced duration of estrus.
• Further, the abnormal sexual behavior observed in mares during steroid treatment persisted for six months after the cessation of treatment. However, this behavior showed a declining trend with the passage of time.
• All mares across all treatment and control groups achieved ovulation by the end of the research period and the interval to first ovulation did not differ significantly among groups.
• Adverse effects were noted in the conditions of the ovarian size, follicular development, and tubular genitalia until the middle of March among the steroid-treated mares. No differences among groups were observed beyond this point.
• Crucially, the first-cycle pregnancy rates showed a decrease with steroid use, with 83% for untreated mares followed by 67%, 50%, and 42% for BU, 4 BU, and ND-treated mares, respectively.

Conclusion

• This study concludes that long-term anabolic steroids treatment adversely affects the fertility of young mares. The negative outcomes include reduced estrous behavior, shortening of estrus duration, abnormal sexual behavior, adverse influence on ovarian functionality and a drop in first-cycle pregnancy rates.
• These insights support the hypothesis that the use of anabolic steroids in young mares can have long-term impacts on their reproductive abilities, significantly affecting their fertility.