It’s that time of year again, daylight savings, taxes and yes, fresh, spring grass pastures. More importantly, it’s time to deal with the problem of the overweight horse. In a 2011 study at the University of Nottingham, England, it was discovered that nearly 54 percent of the horses examined were overweight! This study showed that these horses were maintained on grass and hay, showing that grain or concentrates are not needed to produce an overfed horse and that pasture grass intake must be carefully regulated to manage body weight.
There is nothing wrong with pasture grass for horses. Horses are just so good at grazing and today’s grasses contain such large amounts of carbohydrates, problems can occur. The typical grazing horse spends roughly 70 percent of his time in grazing activity. As an example, 17 out of every 24 hours is in grazing. The remaining 30 percent is devoted to sleep, play, socialization and/or various other assorted herd behaviours. It should be noted that the type and quality of pasture greatly influences grazing time.
According to Michigan State University, College of Veterinary Medicine, 10 percent of a horse’s day is spent walking at pasture looking for food. The poorer the pasture, the more time is spent looking for edible forage, so horses will spend less time grazing on a lush spring pasture than they will on a mid to late summer pasture with poorer quality of grass. In a study done at the Equine Science Division at the Hidaka Training and Research Centre, Japan, they found that horses that we allowed to graze for 17 hours daily on a 10-acre field travelled between 8 – 9.5 miles and burned more calories than horses allowed to graze for only 7 hours on the same field. Those horses travelled only 2.5 – 3 miles with much less energy expended.
In a 2008 study by R.J. Geor, supported the fact that a horse at pasture 24 hours a day and grazing 17 hours will generally consume up to 25 pounds of forage. Since a mature horse needs to consume 2 – 2.5 percent of his body weight daily, this 25 pounds of forage is more than enough for his maintenance needs. If this horse was to be fed any additional feed, then it would be overfed and this would be contributing to him getting fat.
It seems reasonable that the best way of controlling a horse’s carb intake is to limit his access to pasture, especially the nice green, spring pasture. If you reduce pasture time, then you reduce his intake and his chances of overeating…right? This very theory was brought into question by North Carolina State College of Veterinary Medicine. It was showed that if you reduce pasture time available to your horse, he will respond by increasing his grazing intake, so the overall carbs consumed will remain equal. In this very study, there were some horses that we able to consume 17 hours worth of grass intake in only 3 hours of turnout, so limiting turnout will not work.
Another option for controlling overweight horses is to introduce grazing muzzles which are an effective method of restricting pasture intake. A study conducted by Dengie Feeds showed a restricted grass intake with a grazing muzzle of 75 – 86 percent. Muzzled horses had a 50 percent reduction in bite depth and a 62 percent reduction in bite weight. Horses wearing a muzzle simply cannot bit as deeply or get as big of a bit as horses that are not wearing a muzzle.
So when it comes to spring green grass, less means more and a well fitting grazing muzzle may be the answer!