Grazing season makes attention turn to equine metabolic disorders but there is a wealth of misinformation out there, despite solid research that disproves some pieces of advice and a clear lack of supporting research for others.
False: NSC and fructan determine the laminitis risk of pasture/hay/feed for metabolic horses.
True: Abnormally high insulin is the risk factor for laminitis. Only simple sugars and starch can cause insulin elevations. These are measured by ESC (sugars) and starch. Fructan is not a sugar, does not elevate insulin. NSC (nonstructral carbohydrate) = ESC + starch + fructans and overestimates risk. Look at ESC + starch only and keep these below 10% total.
False: It is more dangerous to allow grazing by overweight horses than normal weight horses.
True: Laminitis risk is directly linked only to insulin level, which is not tied to weight.
False: Equine Metabolic Syndrome predisposes a horse to develop Cushing’s Disease (PPID).
True: There is no solid evidence that EMS predisposes to PPID. However, horses with EMS may be more likely to be diagnosed because PPID exacerbates high insulin levels and laminitis risk.
False: High fat feeding is safe for horses with elevated insulin.
True: High fat feeding causes or worsens insulin resistance in all other species where it has been tested. The safety in horses has never been evaluated.
False: Protein supplementation will decrease the need for pergolide in horses with PPID.
True: Only drugs which replace the action of dopamine (dopaminergics), like pergolide, can treat PPID. Feeding more protein will not substitute for pergolide and will not help with the muscle loss associated with uncontrolled PPID.
False: Herbal supplements and acupuncture can reset pituitary function.
True: These are baseless claims.
False: Horses not responding adequately to low dose Prascend for PPID should have cyproheptadine treatment added.
True: It was shown almost two decades ago that cyproheptadine does not help control PPID. There has been no new evidence since then.
False: Obesity, metabolic syndrome and laminitis are inflammatory conditions.
True: While this might seem to make sense, and is true in humans and lab animals, formal research does not support a significant inflammatory component in horses.
False: Only dynamic testing, like glucose challenge or insulin response tests, can accurately diagnose EMS.
True: Horses which test positive with abnormal baseline insulin testing and proxies based on insulin and glucose do not need to be confirmed by dynamic testing. The problem with false negative results on baseline insulin and glucose testing is that the ranges for normal are too high. Field testing published 14 years ago showed upper limit of normal for horses on pasture is 12 uIU/mL and recently published research, validated by intravenous insulin sensitivity testing, established that the upper limit of normal for fasting insulin should be 5.2 uIU/mL. Laboratory “reference ranges” are not the same thing as normal.
Don’t believe everything you read or are told. For up to date information from an independent source whose sole focus for two decades has been the dissemination of accurate, science-based information on metabolic disorders in horses visit http://www.ecirhorse.org and download the free NO Laminitis! conference proceedings.
Eleanor Kellon, VMD