Limiting hay for any horse (but particularly an IR horse) will be counterproductive when it comes to trying to get your horse lose weight. The more weight a horse gains, the more we are told to “decrease their food”. With a laminitic horse, we’re told to lock them up and stop feeding them, to feed them very little hay and of poor quality. This will not work.
The digestive system in a horse was created to always have something moving through it. They are supposed to eat almost continually, in small quantities, and move. We know that an IR horse already has elevated insulin levels and that with ANY horse, insulin increases with the ingestion of sugars. Stress can also increase insulin and this is important plays right along with “not eating” for long periods of the day. An empty stomach is stressful for the horse because it initiates the “survival instinct”. When a horse is “starved”, the higher stress becomes, the more insulin is secreted into the blood stream, causing the levels to rise, essentially leading to an increase in the likelihood of a laminitic episode. (Keeping sugar out of an IR horse’s diet, and increasing movement and exercise is also essential, as is treating the underlying metabolic dysfunction. http://www.forloveofthehorse.com/ems.php )
It has been proven that a free-choice hay diet will eventually eliminate the “starvation stress” and a horse will begin to eat less at each “feeding”. Once the horse learns that they are not going to be without food, they will realize that whenever they feel the need to eat, the food will be available to them and they will begin to consume less over time. With this, the horse will start to self-regulate the amount of hay they eat and this will reduce stress AND keep food flowing in the digestive system, which is much healthier overall.
They may “wolf” hay down for a while, but once you begin to provide it free-choice, they will begin to adjust and eat less. The adjustment may take two weeks, or may take two months. This all depends on how damaged their metabolism is, and how they adjust (mentally and emotionally) to the changes. You may see some weight gain in the beginning, because their instinct has been ignored, in a sense, and they have been “retrained” to eat as much as possible at one time because they do not know when they will get to eat again. Over time, they will adjust and will begin to eat less.
You may even opt to use a hay net or a hay bag with 2” holes (Holes any smaller than 2” may cause frustration and they may not be able to get enough, causing some aggression and more stress.). This will restrict the wolfing of mouthfuls of hay, and still give them the effect of “grazing” by pulling small amounts out at a time. If a net or hay bag is not an option, spreading many flakes around a large area will encourage them to walk from pile to pile to also create a “grazing” effect. This way, they’ll also spend much of their time moving.
This is THE BEST way to feed hay and will cause you and your horse a lot less stress in the end. I have had my recovering IR horse on free choice hay since I acquired her. She has maintained a very healthy weight (as have my other horses) and spends an equal time both at the bale and away from it. They know that hay will always be provided to them, and do not feel the need to gorge themselves even when they are turned out to pasture. They know that food will be there when they feel the need to eat. It’s nice to know we can help reduce their stress and that doing that in itself will make them healthier in the long run!