Effect of surgical manipulation, placental fluid, and flunixin meglumine on fetal viability and prostaglandin F2 alpha release in the gravid uterus of mares.

This research investigated the impact of surgical manipulation, placental fluid and flunixin meglumine on the viability of horse fetuses and the release of prostaglandin F2 alpha, a hormone involved in birth. It found that surgical manipulation and fetal palpation caused a temporary spike in the hormone, the placental fluid injection resulted in fetal death, and the use of flunixin meglumine didn’t ensure the survival of twin pregnancies when one fetus was removed.

Study Layout and Methodology

• The study involved 21 pregnant horses, divided into five groups. The horses carried single or twin fetuses and were at different gestational ages, ranging from 41 to 65 days.
• All horses underwent surgery, specifically a ventral median celiotomy, where an incision is made in the midline of the abdomen.
• The first group, consisting of three mares with a single fetus, underwent uterine manipulation and fetal palpation for 5 minutes.
• The second group of three mares, also with a single fetus, had 250ml of sterile placental fluid injected into the non-pregnant part of their uterus.
• The third, fourth, and fifth groups included horses carrying twin fetuses. One fetus was removed surgically from all the mares in these groups.
• All mares received preventative progesterone treatment until their 100th day of gestation, or until fetus death.

Results and Observations

• The three mares in the first group gave birth to normal, live foals.
• The surgical manipulation and fetal palpation led to a temporary increase in the concentration of the prostaglandin F2 alpha metabolite (PGFM) hormone in the blood.
• The injection of placental fluid into the uterus resulted in the death of the fetus within three hours post-surgery in the second group.
• None of the remaining fetuses in the seven mares with single-horned twin pregnancies (groups 3 and 4) survived.
• Five mares from the fifth group, also with single-horned twin pregnancies, successfully gave birth to a single, healthy foal.
• One more mare from group five had a live fetus four days post-surgery, but she was euthanized due to a fractured femur.