Articles
High NSC Diets in Pregnant Mares, the Link to Insulin Resistance and Cushing’s in Young Horses

High NSC Diets in Pregnant Mares, the Link to Insulin Resistance and Cushing’s in Young Horses

Feeding pregnant mares diets high in non-structural carbohydrates (NSC) , such as large amounts of grain, sweet feeds, or lush pasture , can have long-term effects on both the mare and her foal. Excess NSC leads to repeated spikes in blood glucose and insulin, which can cause the mare to develop insulin resistance during pregnancy. This metabolic imbalance not only impacts the mare’s health but also influences the developing foal through altered nutrient and hormonal signalling in the womb. 

 Insulin resistance in pregnant mares can affect placental function, leading to an increased risk of foals being born with impaired glucose metabolism. These foals may have reduced insulin sensitivity from birth, making them more susceptible to metabolic syndrome and other endocrine disorders later in life. Early hormonal disruption during the developmental phase can permanently influence how the foal’s endocrine system responds to sugar and stress. 

 One long-term consequence of this altered metabolism is a higher risk of early-onset Cushing’s-like disease (PPID) in young horses. When insulin resistance persists, it can contribute to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, leading to elevated cortisol levels. Over time, this can cause degeneration of the pituitary gland, accelerating the onset of PPID , a condition more commonly seen in aged horses but increasingly recognised in younger animals. 

 Preventing these issues starts with feeding management during pregnancy. Providing a low-NSC, fibre-rich diet with controlled energy intake supports steady blood sugar levels, maintains insulin sensitivity, and promotes healthy foetal development. Using feeds such as soaked beet pulp, chaff, or coconut meal (copra), combined with balanced vitamins and minerals, helps reduce metabolic stress on the mare and lowers the risk of passing metabolic vulnerabilities to the next generation.

Why Coolstance copra

Coolstance copra is a low NSC (11%) high DE feed which does not increase circulating levels of glucose and insulin.

Coolstance copra can safely be fed to pregnant and latatcing mares, to foals and weanlings for topline and condition.


insulin mares resistance foals cushings