Preventing Grass Founder

Tara Jo Bina
Countryside Feed Livestock Nutrition

When the calendar turns to March and April, many horses are turned out to graze lush green grass. It’s important to exercise caution though, because overfeeding on grass when it’s rapidly growing can lead horses to founder.

When actively growing in the spring, immature grasses have high concentrations of easily digestible carbohydrates. These sugars, namely fructan, can lead to excessive bacterial activity in the cecum and large intestine when diet changes occur too quickly. As they die off, this bacteria can produce endotoxins not suited to the new diet. These endotoxins get into the horse’s bloodstream and end up reaching the laminae of the hoof, disrupting blood flow and causing inflammation, resulting in a painful and potentially fatal condition called founder.

Unfortunately there isn’t a cure for founder, so prevention is essential. Overweight horses and horses that have previously foundered are more likely to be affected by grass founder. These animals should be monitored closely, or not allowed to graze until grasses mature and growth slows, when fructan and other sugars aren’t as readily available.

Here are some tips for preventing founder:

• Gradually introduce horses to spring pastures and let them work up to longer feeding periods. At first, start with only 30 minutes a day. A few days later, increase the grazing time to an hour, and keep working up from there. This can be achieved by keeping a horse stalled or in a dry lot majority of the day. Grazing muzzles are also an option for limiting horses’ grass consumption while still allowing them the opportunity to exercise freely on pasture.
• Don’t turn your horses out hungry. Keep an adequate supply of quality feed and hay in your horse’s stall so they’re not sent to pasture with an empty stomach.
• Grazing pastures that have a higher concentration of legumes like alfalfa and clover in the spring. These plants have lower fructan content.

Benefits to keeping your horses from eating too much spring grass are two-fold, it also helps advance the health and productivity of your pasture. Overgrazing early in the season can reduce forage yields.

If you have further questions about preventing founder, or would like customized assistance in developing a well-balanced diet for your horses, reach out to your local Countryside Feed nutritionist. We carry a vide variety of quality feeds to help ensure you’re providing your horses with the nutrition they need, when they need it.