The effects of obesity and insulin dysregulation on mare reproduction, pregnancy, and foal health: a review.
Authors: Hallman Isa, Karikoski Ninja, Kareskoski Maria
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Obesity and associated insulin dysregulation increasingly compromise reproductive performance in mares and predispose their offspring to developmental orthopaedic and metabolic disease, yet the mechanisms remain incompletely understood in equine medicine. Hallman, Karikoski, and Kareskoski conducted a comprehensive literature review examining how obesity and hyperinsulinaemia affect mare cyclicity, ovarian function, uterine environment, gestation, lactation, and foal health outcomes. The evidence demonstrates that metabolic dysfunction disrupts oestrous cycles, impairs follicle development, alters intrauterine conditions, increases pregnancy complications, and programmes long-term disease susceptibility in offspring through both direct fetal effects and lactational transfer of metabolic dysfunction. The practical implications are substantial: farriers and equine practitioners working with breeding mares should recognise body condition and metabolic status as critical determinants of reproductive success and foal welfare, not merely aesthetic concerns, whilst nutritionists and veterinarians managing breeding stock should prioritise insulin sensitivity assessment and weight management as foundational interventions. This review underscores that addressing obesity in mares extends beyond individual animal welfare to safeguarding the health trajectory of future generations, making metabolic screening and conditioning protocols essential components of professional equine care.
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Practical Takeaways
- •Maintain mares at optimal body condition score before breeding—obesity-related metabolic dysfunction impairs fertility and compromises pregnancy outcomes, affecting both mare and foal health
- •Monitor insulin status in overweight or insulin-dysregulated mares, as hyperinsulinemia during pregnancy increases foal susceptibility to developmental orthopedic disease and metabolic problems later in life
- •Consider weight management and metabolic assessment as essential preventative strategies for reproductive success and long-term foal welfare, not just a cosmetic or general health issue
Key Findings
- •Obesity and insulin dysregulation impair mare cyclicity, ovarian function, and uterine environment through metabolic disruption
- •Hyperinsulinemia in pregnant mares increases risk of gestational complications and predisposes foals to later-onset orthopedic and metabolic disease
- •Maternal metabolic dysfunction during gestation and postpartum period directly affects foal health outcomes beyond the neonatal period
- •Equine metabolic syndrome effects on reproduction represent a significant welfare concern across modern horse populations with implications for offspring generations