Grass – Feed With Caution
By Marijke van de Water
Grass is the most natural thing a horse could eat, right? Surprisingly this is no longer true, although it used to be; today our horses eat a very different type of grass in the pasture. Pasture grasses, particularly cool weather grasses such as brome, timothy and orchard grasses, are much higher in sugars and also contain fructans – a low fibre, modified sugar which horses cannot easily digest. Fructans were introduced into our grass crops over the last two decades to fatten beef cattle and to increase dairy milk production but this “magic” ingredient for cow farmers has had a seriously damaging effect on our horses and grass is now implicated in several equine health conditions.
Sugars and starches are normally digested with enzymes in the small intestine. But when sugars and starches are ingested in excess the small intestine cannot digest them all completely thus any mal-digested feed is now passed on into the cecum in the hindgut for fermentation. However, the only food group that should be fermented in the cecum is fibre, from where horses get most of their energy. The cecal fermentation of sugars and fructans therefore causes abnormal levels of gas production (often causing colic), heat and lactic acids – the acids destroy beneficial bacteria (probiotics) but are favoured by harmful strains of bacteria such as Salmonella, Streptococcus, and E. Coli as well as yeast cells. These pathogens then produce a variety of different toxins that are very damaging to the colon walls. This cocktail combination of gas, heat, acids and toxins is known as cecal acidosis, a condition that not only permanently disrupts the natural balance of microflora, but damages the intestinal lining of the colon making it abnormally permeable. Known as “leaky gut syndrome” the damaged colon allows the migration of bacteria, yeast, acids, and related toxins to leak across the membranes, out of the colon and into the general body systems affecting the liver, kidneys, heart, muscles, joints, immunity, and the ever sensitive lamina hoof tissue – high sugar/grass diets are the leading cause of laminitis in horses. Leaky gut is also a factor in arthritis, skin conditions, digestive disorders and poor immunity.
High sugar-carbohydrate and fructan diets from grass are also the primary cause of insulin resistance. Liver and muscle cells are lined with receptors that allow the sugars to enter and convert to glycogen, the storage form of sugar. Normally these receptors are prompted to open with insulin, a hormone that is produced by the pancreas. However, in the case of insulin resistance (Equine Metabolic Syndrome) the receptors no longer open and the sugar is forced to be stored as fat instead. Thus the insulin resistant horse or pony most often presents with fat pads and/or a crested neck. Insulin resistance leads to obesity, poor immunity, fatigue, joint pain, hormone imbalances including Cushing’s disease and the ever-prevailing laminitis.
Some horses can also experience digestive problems transitioning from hay to grass or grass to hay which indicates that they are not efficiently fermenting the fibre or digesting the sugar. Because hay and grass differ in types of sugar and starch as well as moisture content they each require different species of fermentative bacteria. This is why a horse’s diet must always be changed over slowly, so that the different species of friendly bacteria (probiotics) in the hindgut have time to adapt rather than die off. The process of fermentation is accomplished with billions of units of various strains of bacteria. To support this dietary transition, especially if horses exhibit symptoms, horses should be supplemented with probiotics. Horses, perhaps more than any other species, rely on a high level of probiotics to maintain a balanced ecosystem in the gut. A deficiency of probiotics can cause bloating, colic, diarrhea, leaky gut, bacteria and yeast infections, poor immunity, unhealthy weight loss or gain and/or vitamin deficiencies. In all cases of digestive problems, colic, leaky gut, weight loss or gain, insulin resistance and laminitis (whether they are on grass or not) the hindgut should be replenished with live bacteria. A good probiotic should be refrigerated to maintain maximum potency. Riva’s Remedies Pro-Colon is kept refrigerated right up to the point of shipping and is specifically formulated for horses.
If your horses are heading out on grass for the first time be sure and introduce them slowly. It is best to start them with twenty to thirty minutes of grazing for the first two or three days and then gradually increase by twenty to thirty minutes every day until they are up to four to five hours of grazing time. This generally takes ten to fourteen days. The best grazing times are early in the morning and later in the evening when the grass is lower in sugar. How much grass grazing a horse can tolerate is variable and depends on breed, level of exercise, lifestyle, health history, grass type and the local climate. Some horses cannot be free-grazed at all while most others should be limited.
And whereas hay is lower in sugars than grass because of the cutting, drying and baling process, sensitive or “at-risk” horses fed hay cut from these high sugar pasture grasses can also develop metabolic and/or hoof laminitic problems.