Medical induction of maternal behavior in nurse mares and foal-rejecting mares undergoing foal grafting: a retrospective study of 140 cases

BACKGROUND: Medical induction of maternal behavior can be a safer and less stressful way to introduce orphan foals to nurse mares, compared with traditional methods that are time consuming and require restraint of the mare. Published data on results of medical treatment in a large number of mares are lacking. HYPOTHESIS/OBJECTIVES: Describe a hormone-based protocol for foal grafting, including nonsteroidal anti-inflammatory drugs, dinoprost tromethamine, and oxytocin, and to report treatment outcome. ANIMALS: A total of 113 nurse mares and 27 mares that had rejected their foals. METHODS: Retrospective case series. Cases were retrieved through a record search from a nation-wide veterinary field practice and from one equine referral hospital in Sweden. RESULTS: Overall, 71% of the cases had a successful outcome. In most successful cases, acceptance was immediate with minimal restraint of the mare required. Mares that rejected their foals at birth had a worse treatment outcome (52% successful) than nurse mares (76% successful). CONCLUSIONS AND CLINICAL IMPORTANCE: The foal-grafting protocol was a time-efficient, safe, and effective alternative to traditional methods. Considering the decreased need for restraint of the mare it also has animal welfare benefits. No adverse effects other than profuse sweating were reported in the treated mares.