The effects of maternal health and body condition on the endocrine responses of neonatal foals.
Authors: Ousey J C, Fowden A L, Wilsher S, Allen W R
Journal: Equine veterinary journal
Summary
# Editorial Summary Maternal nutrition during pregnancy programmes metabolic function in the developing foal, with potential consequences extending well beyond the neonatal period. Researchers compared ten first-time mares fed either maintenance or high-plane diets throughout pregnancy; all subsequently lost approximately 10% body mass due to natural *Streptococcus equi* infection during mid-gestation. Whilst maternal insulin and glucose concentrations fell significantly during and after the illness, foals born to mares on maintenance feeding showed markedly elevated insulin responses during glucose tolerance testing compared with foals from well-nourished mares—indicating enhanced pancreatic beta cell sensitivity to glucose. Notably, the hypothalamo-pituitary-adrenal axis responses appeared unaffected by maternal nutrition status, suggesting selective programming of metabolic rather than stress-response pathways. These findings indicate that the combination of chronic underfeeding and acute nutrient restriction from illness during mid-gestation can alter neonatal insulin dynamics, with implications for metabolic disease susceptibility later in life; practitioners managing mares through illness or poor forage years should recognise that even apparently healthy foals at birth may have altered glucose metabolism that warrants nutritional management strategies during their growth phase.
Read the full abstract on PubMed
Practical Takeaways
- •Pregnant mares experiencing illness-induced weight loss may program altered metabolic responses in foals even when foals appear clinically normal at birth—monitor offspring for metabolic issues throughout development
- •Pre-existing maternal body condition (maintenance vs. high) influences how foal pancreatic beta cells respond to gestational stress, suggesting nutritional management of pregnant mares has long-term metabolic consequences for offspring
- •Acute maternal nutritional challenges during mid-gestation appear more consequential for foal endocrine programming than HPA axis function, so focus preventive health strategies on minimizing maternal feed intake disruptions during this period
Key Findings
- •Acute nutrient restriction in mid-gestation due to maternal illness enhanced insulin secretion to glucose in neonatal foals, with higher insulin concentrations in foals from maintenance-fed mares compared to high-plane-fed mares (P < 0.05)
- •Maternal insulin and glucose concentrations decreased during and one month after the weight loss period, but foal cortisol and glucose responses to exogenous hormones were similar between groups
- •Pancreatic beta cell function showed nutritional programming effects dependent on pre- and post-weight loss nutrition levels, while HPA axis function did not appear similarly affected
- •Enhanced neonatal pancreatic beta cell sensitivity may predispose foals to metabolic problems in later life despite normal birth parameters and health status