‘Early-morning grass isn’t always safe’: laminitis prevention advice for owners after new research
Advances in feeding and managing horses to reduce risk of laminitis are being shared following a significant body of recent research.
Scientists presented new findings, undertaken in collaboration with equine feed company Spillers, on laminitis risk, grazing management and the equine microbiome at the 13th European workshop on equine nutrition in Lisbon last month.
They gave eight presentations covering 11 studies, of which seven offered new insights into reducing the risk of laminitis and advancing understanding of the equine digestive system and microbiome.
This huge body of research has also resulted in valuable findings and practical advice for owners.
“It is excellent that research like this is under way”
H&H vet Karen Coumbe
Most cases of laminitis are related to high levels of insulin in the blood. In many, it is triggered by an equine eating enough non-structural carbohydrate (NSC) or “starch and sugar” to raise insulin levels.
Spring grass was shown to contain consistently high levels of NSC through the day and overnight, resulting in high insulin levels in horses with insulin dysregulation (ID) and some non-ID horses.
In late summer, NSC levels in grass peaked at 7pm and were lowest early in the morning. Insulin responses in ID horses mirrored these changes.
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Moving from grass to a grass-free dry lot and feeding low NSC hay significantly reduced insulin levels after 24 hours in five of the six ID horses studied.
Grazing muzzles may help reduce insulin response in some horses, although their effectiveness varies between individuals and may be influenced by grass NSC levels.
“In terms of practical advice for horse owners the studies show we mustn’t assume early morning turnout is always safe during periods when grass NSC levels remain high,” said Edd Knowles, science and nutrition director at Mars Horsecare, Spillers’ parent company.
“Even metabolically healthy horses can produce high amounts of insulin when grazing high-NSC pasture, while insulin-dysregulated horses may still require restricted grazing even when grass sugar levels are relatively low.
“Complete removal from pasture may be necessary for horses at greatest risk especially during high-risk periods such as spring and autumn, while veterinary guidance and individual testing remain essential, as horses can respond very differently to the same forage.”
H&H vet Karen Coumbe, who was not involved in the studies, told H&H research in this area is “so very important”.
“Weight control needs to be taken seriously in horses and it is excellent that research like this is under way to provide evidence as to what is the best course of action,” said Dr Coumbe.
Pat Harris, who co-authored all eight abstracts presented with Spillers, told H&H these are part of a series of studies undertaken at the University of Kentucky with Dr Amanda Adams that are trying to provide better advice on the level of NSCs that should be provided, especially in severely ID horses.
She said this work has enabled Spillers to give a guide starting point from which people can then work with the vet and nutritionist, but stressed that horses are all individuals.
“Using this research Spillers has put together good general advice, which is very valuable and gives some good starting points, but you may have to tailor it and consider monitoring for an individual animal, especially if you're concerned,” said Dr Harris.
She suggested that for owners concerned about the NSC levels of their pasture, 3-7pm would be a good time to test their animals for insulin. Dr Harris also noted that even if a horse is out on a low-NSC pasture, using a properly fitted grazing muzzle, may help reduce insulin even further and might help reduce the risk of obesity.
She also agreed with Dr Knowles that during periods when pasture NSC levels are high, there is “no real safe time” especially for a severely ID animal to be grazing and noted that it is not only overweight or obese animals that can be ID.
“Even some of the non-ID horses when turned out on that high-NSC pasture also ended up with high insulin values,” she said. “Just because you've tested your animal and found they are not insulin dysregulated, it does not mean there is not a laminitis risk when they're out on high-NSC pastures.”
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Lucy is an experienced news journalist, reporter and presenter. Since joining the Horse & Hound team in 2015, Lucy has reported from major global sporting events including the Tokyo Paralympic Games and multiple European Championships, as well as Badminton, Burghley and London, to name a few. She has covered current affairs and sports news across the full spectrum of equestrian disciplines and racing, as well as human and equine welfare, industry news and court cases.