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

Overview

• This study evaluated a hormone-based medical protocol aimed at inducing maternal behavior in nurse mares and mares that rejected their foals, facilitating quicker and less stressful bonding with orphan foals.
• The protocol was found to be effective in about 71% of the cases, offering a safer, faster, and more welfare-friendly alternative to traditional foal-grafting methods.

Background and Rationale

• Introducing orphan foals to nurse mares traditionally requires time-consuming methods involving physical restraint and sometimes sedation of the mare.
• These traditional methods can be stressful for both mares and foals, raising animal welfare concerns.
• A medical approach using hormones and anti-inflammatory drugs has been proposed to induce maternal behavior faster and with less stress.
• Prior to this study, there was limited data on the effectiveness of such treatments in a large number of mares.

Objective

• To describe a hormone-based treatment protocol for foal grafting that includes nonsteroidal anti-inflammatory drugs (NSAIDs), dinoprost tromethamine (a prostaglandin), and oxytocin.
• To evaluate the treatment outcomes in nurse mares and mares that rejected their own foals.

Methods

• Design: Retrospective case series reviewing 140 cases.
• Subjects: 113 nurse mares and 27 foal-rejecting mares undergoing foal grafting procedures.
• Data Sources: Case records were collected from a national veterinary field practice and one equine referral hospital in Sweden.
• Treatment: Administration of a hormone-based protocol involving NSAIDs (to reduce inflammation and stress), dinoprost tromethamine (likely to help induce uterine contractions and possibly affect behavior), and oxytocin (a hormone known to stimulate maternal instincts).

Results

• Overall success rate was 71%, meaning the mare accepted the foal with minimal restraint and often immediately.
• Differences between groups:
  • Nurse mares had a higher success rate (76%) of bonding with orphan foals.
  • Mares that had rejected their own foals at birth had a lower success rate (52%) for acceptance.
• The majority of successful cases required minimal restraint, indicating less stress on mares and foals.
• Adverse effects were minimal, with profuse sweating being the only reported side effect.

Conclusions and Implications

• The hormone-based foal-grafting protocol is a safe, effective, and time-efficient alternative to traditional methods.
• Reduced need for physical restraint and sedation benefits animal welfare by decreasing stress during the bonding process.
• Veterinarians and breeders can use this protocol to improve outcomes when introducing orphan foals to nurse mares, especially in cases where mares have difficulty accepting foals.
• Further research could optimize the protocol and explore long-term behavioral effects on mares and foals.