The effect of intra-uterine devices on the reproductive physiology and behaviour of pony mares.

This study examines how glass intra-uterine devices (IUDs), often used to modify sexual behavior in performance mares, affect the reproductive physiology and behavior of pony mares. The researchers found that while the IUDs were well-tolerated, they didn’t produce any noticeable changes in the mares’ reproductive bodies or behavior.

Research Methodology

• The researchers studied the effect of spherical (35mm diameter) glass intra-uterine devices (IUDs) on nine nulliparous (never gave birth) pony mares during their natural breeding season.
• The mares were approximately 4.6 years old with a bodyweight of around 230 kg.
• The mares were divided into two groups. One group received the IUD implantation and the other group received a sham treatment for control.
• They monitored and evaluated a total of 50 ovarian cycles, including 26 cycles before the treatment and 12 cycles after treatment for each group.

Research Findings

• The study found that the IUDs were well-tolerated by the mares.
• No noticeable changes were recorded in the mares’ reproductive physiology or behavior. This includes the functions of ovaries and uterus, endocrine components (luteinising hormone, oestradiol, progesterone, testosterone), as well as sexual and social behaviours associated with their ovarian cycle.

Implications of the Study

• The results of this study suggest that while IUDs are well tolerated by pony mares, they may not have the intended effects on reproductive physiology or behaviour as previously believed.
• This detailed analysis of the cyclic reproductive changes in pony mares could be useful for developing and implementing controlled breeding programs.
• Future research might need to investigate other methods or interventions to modify the sexual behaviour of performance mares.