FEBRUARY 2024 THE RIDER /27 2024 - The Winter of the Hay Belly My horse looks fat!


But when I check his Body Condition Score, he is under 6: I can easily feel his ribs and there are little to no fat deposits along his neck, withers, shoulders, back or tail head. My


horse, the


palomino in the photo, has a very large hay belly this winter. But he is not obese. It’s been important for


me to realize the difference and how the hay belly is caused. 2023 was a tough year


for harvesting hay in On- tario. Record rainfall in June and July resulted in few consecutive days of the sun- shine needed to cut, dry and bale hay. A lot of first cut hay was harvested later in the summer, when the crops were overly mature. Digestibility of hay is


affected by maturity. Hay cut when it is overly mature has more fibre and is less di- gestible. Hay that is too high in indigestible fibres can in- crease the risk of gastroin- testinal disturbances and cause the infamous hay belly.


Our horses live outside


on a track system with free access to shelter in a large, cozy bank barn. In winter, they are not blanketed, and they choose to be outside most of the time day and night. They are on a forage-


Whisky, the 25 year old palomino, with the big hay belly and body condition score 5.7


first diet and always have access to hay in their Opti-


Mizer slow feeders. They forage what they need,


when they need it. Digesting hay fibre in their hindgut is


their main source of ad- justable body heat. I like to think of hay as the fuel that keeps the “furnace” going in the horses’ body. In bitter, cold weather they dial up the amount of hay to keep themselves warm. Given the challenging


hay yield last year, it was particularly important to test our hay so that we could try to make the best out of what we were able to get. Our hay was first cut, mostly grass from the same farm. About half of it was har- vested at the normal time, but the other half was har- vested very late in the sea- son (late July/early August). Comparing the digestibility of these 2 cuts, we looked at:


1. Lignin. This is the in- digestible fibre in the hay. 2. ADF (Acid Detergent Fibre). This measures the


least digestible fibres which includes lignin and cellu- lose. ADF is negatively cor- related with digestibility, so the higher the number, the less the hay will be broken down inside a horse’s gas- trointestinal tract. It also dis- tends the digestive tract, resulting in the hay belly. 3. NDF (Neutral Deter- gent Fibre). This measures all the fibre in the hay, in- cluding ADF and hemicellu- lose. NDF is negatively correlated with forage in- take, so the higher the num- ber, the less hay a horse will eat.


Overall, the very ma-


ture hay has very low di- gestibility. To make the best of it, we used it early in the season, when the horses still had some late autumn grass available. As the winter pro- gresses, we are mixing it in each OptiMizer with two


other cuts of hay that are more digestible. With this fi- brous hay, we wanted to en- sure the horses had plenty of water to drink, so we added a second water source, closer to their foraging area. Hay is so vital to a


horses’ diet and health. And yet it can be so variable. It is important to get hay ana- lyzed to fully understand it and optimize feeding it. This year, it also helped me un- derstand why my horse has such a large hay belly- it’s filled with much more fibre than usual! I know his belly will quickly melt away in the spring once he gets started on pasture. In the meantime, I have to keep telling myself that he is NOT fat, despite looking like he is.


By Sue Wilson


Wishing Well Services, Ltd info@hayoptimizer.net


Is Winter Pasture Safe for Metabolic Horses?


By Linaya Pot, MSc, Equine Nutritionist at Mad Barn


If your horse has


Equine Metabolic Syn- drome (EMS), you’ve likely been advised to steer clear of spring and fall pasture grasses. During these sea- sons, the high sugar content of grasses can be problem- atic for EMS horses. Some plant sugars,


termed hydrolyzable carbo- hydrates, trigger an insulin response in horses. After consuming these


hydrolyzable carbohydrates, an EMS horse will have trouble regulating their blood insulin. This leads to high insulin levels that can compromise blood flow to the hooves and cause laminitis. To minimize this risk, metabolic horses are typically kept off high-sugar pastures during spring and fall.


However, the dangers


of winter pastures are less well understood. Despite their dormant and dead ap- pearance, winter grasses can still pose a risk to EMS horses.


Types of Sugars in Winter Grasses Plants adapted to sur-


vive long periods of low sunlight and cold tempera- tures store large amounts of energy as carbohydrates. They use these storages to help survive long winters. These carbohydrates are pri- marily found as fructans or


sucrose. Sucrose is a hydrolyz-


able carbohydrate since it is easily digested, rapidly ab- sorbed and contributes to high insulin levels. Grasses that are high in uscrose are not considered safe for EMS horse.


Fructans are large car-


bohydrates made up of su- crose. Since they are larger and more complex, fructans are not easily digested and do not contribute to spikes in insulin. A plant with lots of fructans does not pose the same risk for an EMS horse as a plant that is high in su- crose.


However, plants can


breakdown their fructan storages release the smaller sucrose particles. Many plants will release sucrose from the fructan stores for protection during cold weather.


Sugar Trends in Winter Grasses To


survive cold


weather, grasses need to protect themselves from freezing. Freezing causes damage by dehydrating plant cells and damaging their membranes. To protect themselves freeze damage,


against


plants can release sucrose from their storages. The su- crose helps protect the plant by making it more difficult for the water inside the plants to freeze. This release of sucrose


during freezing tempera- tures leads to high levels of hydrolyzable carbohydrates in the base of the plant. These grasses would be con- sidered high-risk for a meta- bolic horse since it can trigger an insulin response. Unfortunately,


it is


hard to predict what plants will rely on sucrose for pro- tection, or when they will release their sugar storages. There can be a large varia- tion in the sugar levels of winter pasture grasses due to plant variability and tem- perature fluctuations.


Winter Risks for EMS Horses Variability in winter


pasture is not the only risk to EMS horse. Cold weather can also contribute to laminitis risk. Horses will naturally


reduce blood flow to their extremities


weather. This leads to less blood reaching the hooves. While this is not an


issue for a healthy horse, some EMS horses can al- ready have reduced blood flow from their high insulin levels. Reduced circulation


in freezing


during cold weather, com- bined with high insulin lev- els, can restrict blood flow to the hooves and lead to winter laminitis. Winter laminitis com-


monly occurs after a sudden and extreme drop in temper- atures. Unfortunately, this is also the time when some pasture grasses will be re- leasing sugars to help pro- tect


themselves


freezing damage. While more research is


needed to understand how winter pasture impacts laminitis risk in horses, the compounded risk from plant sugars and cold tempera- tures does create a risky time for metabolic horses. Even though the grass ap- pears dead and safe, it is best to assume that winter pasture grass is not safe for horses.


How to Manage Metabolic Horses on Winter Pasture If you suspect your


horse may be metabolic and is on winter pasture, imple- ment these techniques to keep them safe: 1. Provide plenty of dried hay: Offering dried hay as an alternative forage source may reduce pasture intake 2. Limit pasture turnout until there is adequate snow cover: A thick, hard layer of snow makes it harder for horses to reach grass, dis- couraging intake and pro- moting energy expenditure. 3. Use a grazing muzzle: Most wintering plants store


from


their sugars in the roots or the base of their stem. Use a grazing muzzle if you notice your horse pawing through the snow to reach these sug- ary parts. 4. Monitor your horse: Reg- ularly testing for insulin lev- els can help determine if your horse has an abnormal insulin response to pasture and should be removed from grass. Given that plants use


hydrolyzable carbohydrates to protect themselves during winter, it is crucial not to as- sume winter pasture is safe for metabolic horses. Imple- menting these precautions can help mitigate the risks associated with winter laminitis and insulin-related health issues in horses with metabolic syndrome.


Linaya Pot Linaya was born on a


small, family-run dairy farm


in Southwestern Ontario. She spent much of her child- hood caring for the farm’s animals, including several horses, pygmy goats and sheep. This fostered a pas- sion for animal husbandry and care. Linaya attended the University of Guelph where she received her B.Sc in Animal Biology and a M.Sc in Dairy Nutrition. While studying at univer- sity, she continued to de- velop


her equestrian


abilities by joining the Uni- versity of Guelph Eques- trian Club. After graduating from school, she worked in the agriculture industry as a consulting


nutritionist.


While most of her nutrition work involved cattle, she also formulated diets for sheep, goats, deer and ham- sters. She came to work at Mad Barn where she could unite her passion for nutri- tion and the equine industry.


Linaya Pot


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