Seasonal Insulin Responses to the Oral Sugar Test in Healthy and Insulin Dysregulated Horses

A practical approach to hyperinsulinaemia in horses with equine metabolic syndrome

“…Dietary modification is a critical component in the management of hyperinsulinaemia in horses with EMS (Durham et al., 2019). Studies in ponies with ID suggested that the insulin response to oral sugars might be one of the most important predictors of laminitis risk (Meier, de Laat, et al., 2018; Meier, Reiche, et al., 2018), and reducing post‐prandial hyperinsulinaemia is therefore paramount in preventing HAL (Macon, Harris, Bailey, et al., 2022; Macon, Harris, Barker, & Adams, 2022). If the animal presents with suspected HAL, it is essential that any feeds high in non‐structural carbohydrates (e.g.…”

“…Regardless of the dietary strategy implemented, the post‐prandial insulin response to diet and pasture is variable between horses and measuring pre‐ and 60–90‐min post‐ingestion (Macon, Harris, Bailey, et al., 2022; Macon, Harris, Barker, & Adams, 2022) or post‐grazing insulin is advisable to determine the individual's response to their current feed. This will inform future dietary recommendations.…”

“…Season might potentially impact the repeatability of the OST, however, studies to date have yielded conflicting results (Karikoski et al., 2022; Macon, Harris, Bailey, et al., 2022; Macon, Harris, Barker, & Adams, 2022) One study from Finland found no differences in the insulin responses to the OST across seasons (Karikoski et al., 2022), however, a recent study from Kentucky found significant effects of season on insulin responses to an OST in both ID and non‐ID horses over a 2 year period (Macon, Harris, Bailey, et al., 2022; Macon, Harris, Barker, & Adams, 2022). The latter study found that basal and insulin responses to an OST were higher in spring compared to autumn and summer and winter OST responses were higher than the autumn (Macon, Harris, Bailey, et al., 2022; Macon, Harris, Barker, & Adams, 2022). Clinicians should therefore consider seasonal variation when monitoring horses using the OST.…”

Obesity and obesity‐associated metabolic disease conditions in Connemara ponies in Ireland

“…36 Horses with ID have demonstrated seasonal changes in their serum insulin concentration. 37 One study of 22 horses followed over 2 years demonstrated that horses with hyperinsulinaemia had the lowest insulin concentration (60 min post-OST) during the fall season compared to all other seasons. 38 However, a recently published study using the OST in Finnhorses to evaluate the seasonal insulin sensitivity variation over a year, suggested that the variation in the result obtained could be due to the lack of OST repeatability and not the effect of the season per se.…”

“…The months from June to December appear to be the time of the year when the insulin response to glucose is higher, especially in pregnant mares and geldings 36 . Horses with ID have demonstrated seasonal changes in their serum insulin concentration 37 . One study of 22 horses followed over 2 years demonstrated that horses with hyperinsulinaemia had the lowest insulin concentration (60 min post‐OST) during the fall season compared to all other seasons 38 .…”