Grasses, Pasture and Horse Health

The truth behind myths about grazing and grasses, part 1 of 2

by Alayne Blickle, Horses for Clean Water

As an environmental educator in the horse property management field, I visit a lot of horse properties and talk with many horse owners. One of my biggest concerns in pasture management is how owners integrate their horses into the management process, particularly when it comes to grazing and the overweight horse, fondly referred to as the “easy keeper.” In this two-part series, I will talk about how to manage the easy keeper on pasture and attempt to help unravel some common horse health myths surrounding pasture management. The first of these myths is that short grass is good for horses.

Short and Sweet

Over the years, pasture grasses and related grazing principles have been developed for horses through the cattle and sheep industries. This means we have developed grass species with extremely high levels of sugars and carbohydrates that are good for fattening up animals bound for milk or meat production and early age slaughter. These same high-sugar grasses in excessive amounts are not necessarily good for horses, which are athletes intended to live 25-plus years. There are many in the horse industry struggling to develop a better understanding of the issues surrounding sugars, non-structural carbohydrates, and grasses for horses, including vets, farriers, agronomists, horse owners and others.

In horses, “fat” is not healthy. The related high sugar and non-structural carbohydrate issues in hay and grass may explain why we are now seeing so many overweight individuals with metabolic disorders and insulin resistance problems. It may be that the types of pastures we've developed and the way we've been grazing horses are contributing to very serious equine health issues.

If your horse is overweight or already suffering from a metabolic disorder (Cushings, laminitis, Equine Metabolic Syndrome, insulin resistance, Polysaccharide Storage Myopathy, etc.) you need to research options for reducing sugars and carbohydrates in your horse’s diet. Even if your horse doesn’t have one of these problems, watching your horse’s waistline and doing your best to keep him in good health is smart.

Often the easy keeper is simply placed on an overgrazed pasture, commonly called the “diet pen.” Unfortunately, the overgrazed pasture is anything but a diet pen because the greatest amount of sugar in a grass plant is in the bottom three inches. The other common myth I hear is that grass that has gone to seed is good for a horse; this is simply not true. The pasture grass seed-head is another high-sugar part of the plant. Mowing your pasture before the plant produces a seed head will force the plant to produce more leaves (called tillers), which are better for the horse to eat. At this point, the sugars in the plant are more evenly distributed instead of being concentrated in the seed head.

Spring Feeding

Another major myth I hear is that springtime grazing is bad for horses. Again, this is simply not true. When a grass plant is actively growing, as it is in the spring, it is using up its stores of sugar to produce new growth, thereby leaving less sugar in it. When a grass plant is stressed, such as when there’s not enough rain or during cold temperatures, the plant stores sugar and waits for the ideal conditions in which it can start actively growing again. This explains the big growth spurt you often see in droughty pastures after a summer rain. The grass had accumulated sugars and was just hanging out, waiting to jump into action once ideal conditions occurred. This means that brown grasses experiencing stress can have a higher amount of sugar in them than actively growing green grasses.

What is true about springtime grazing is that any change in a horse’s diet can cause digestive upset to the friendly bacteria, creating serious health issues. I always recommend any dietary changes be done on a gradual basis. So, if your horse isn’t used to being on pasture, begin springtime grazing for the “normal” horse at an hour or half an hour at a time. Over a period of several weeks, work your horse up to a couple of hours. Keep an eye on the horse’s weight and consult your veterinarian regarding any questions or concerns.

Next month we will cover some simple guidelines for grazing your horse and managing the overweight horse on pasture.