Reconception of mares following termination of pregnancy with prostaglandin F2 alpha before and after day 35 of pregnancy.

The objective of this research study is to evaluate the impact of using prostaglandin F2 alpha to terminate pregnancies in mares at different gestation stages, specifically before and after day 35, and to assess the success rate of re-conception post termination.

Background

• In situations such as misalliance or diagnosis of twins, equine pregnancies need to be terminated. The success in achieving re-conception post termination is crucially important.
• By day 36 post-ovulation, endometrial cups, which secrete equine chorionic gonadotropin, are established. They prohibit the return to regular oestrus and ovulation for several months, even after a pregnancy is terminated.
• This study was established to compare the effect of abortion with prostaglandin F2 alpha in a group of mares at approximately 30 days of pregnancy and another group exceeding 35 days.

Methodology

• The trial was implemented from October 1983 till February 1984, in the southern hemisphere’s spring and summer, using Nooitgedacht-type pony mares. Pregnancy was confirmed by rectal palpation.
• Two groups of mares, categorized based on their gestation periods, were treated with 5 mg of prostaglandin F2 alpha. Group A had 11 mares between 26 to 31 days of gestation, and Group B included 9 mares between 39 to 50 days of gestation.
• An essential note is that seven of the mares in Group B had previously been in Group A and had successfully conceived after their pregnancy was interrupted.
• Mares were subjected to daily teasing from the first day of treatment. As soon as signs of oestrus were shown, they were examined.

Implications

• Through comparing two groups exposed to different durations of gestation, this study provides valuable insights into the effects of prostaglandin F2 alpha-induced abortion in mares and the success of re-conception post-abortion.
• Understanding these dynamics can shed light on equine reproductive health and management strategies, especially when the need arises to terminate the pregnancies in mares due to specific circumstances.