A 12-year-old 500-kg (1,100-lb) nulliparous American Paint mare was admitted to the veterinary teaching hospital at the University of Florida College of Veterinary Medicine because of signs of colic following natural breeding. The farm manager reported that the mare had been bred 3 times over a 72-hour period during estrus. The breeding behavior of the stallion was unremarkable, but blood was detected on the stallion's penis at dismount following the final breeding. Colic-like behavior was detected in the mare approximately 30 minutes after the final breeding. The mare also postured to urinate and intermittently passed hemorrhagic vulvar discharge.
A 15-year-old Thoroughbred mare at 283 days of gestation was examined to determine the cause of frank, hemorrhagic vaginal discharge. The mare was from a large breeding farm and had been housed with other broodmares, none of which had any signs of reproductive problems. The mare had had 8 previous pregnancies, all with no complications.
The hemorrhagic discharge had been evident for 2 days and was believed to be increasing in quantity. The referring veterinarian had detected placental abnormalities during ultrasonography. The mare had no other outward signs of disease and did not appear to be in discomfort.
Case Description—A 19-year-old Thoroughbred mare was evaluated at 265 days of gestation with a markedly distended abdomen and edema of the ventral portion of the abdomen.
Clinical Findings—The uterus was distended over the pelvic rim, making transrectal palpation of the fetus impossible. Transabdominal ultrasonography revealed excessive amounts of fetal fluid. Results of analysis of fluid obtained via amnio- and allantocentesis confirmed that the amniotic cavity was large.
Treatment and Outcome—The mare was monitored for signs of weakness of the prepubic tendon and abdominal wall. The fetus and placenta were monitored for signs of stress and pending abortion. Flunixin meglumine and altrenogest were administered to the mare. Parturition was attended and occurred at 321 days' gestation. Postpartum complications in the mare included hypovolemic shock and cardiac arrhythmias. Both conditions were treated, and the mare recovered. The foal was considered small, had bilateral angular limb deformities, and was unable to nurse. The foal was given plasma for failure of passive transfer of immunity. Ten months later, the foal underwent procedures to correct limb deformities.
Conclusions and Clinical Relevance—Hydrops conditions are rare in horses, with hydrops allantois occurring more frequently than hydrops amnion; reportedly result in fetal or neonatal death; and may result in death of or injury to the mare. Close monitoring of maternal and fetal health in combination with supportive treatment of the mare can result in the safe progression of a hydrops pregnancy and the birth of a live foal.