Wednesday, August 31, 2011

Why Feeding Twice a Day Isn't Enough



Horse eating out of 1.5" hole size Nibblenet


I just came across an ad for a training barn that mentioned the fact that they feed "twice a day", as if this were a selling point. While it is a common practice in the horse industry to feed on a twice daily schedule, this is terribly inadequate if you look at the horse's biological requirements. Please allow me to explain why.

Horses were designed by nature as "trickle feeders", meaning that they are meant to take in small amounts of food over a long period of time. In natural settings, horses graze at least 16 hours a day, with the pattern being nibble a little, walk a bit, nibble a little more. The whole physiology of their digestive system is set up to accommodate this model of consumption, starting with the fact that horses are constant acid secreters. This differs from humans, whose stomachs only secrete acid in the presence of food. The stomach of the horse, however, produces hydrochloric acid at all times, whether there is food in the stomach or not.

What happens when there is no food in the stomach of a horse? Gastric ulcers happen -- and they happen in an alarmingly high percentage of domestic horses, though many owners never have a clue (see other articles on ulcers in this blog for more details). Studies (e.g. the 2009 one performed at the University of Copenhagen by Nanna Luthersson, et al) have shown that going more than six hours without eating puts horses at tremendous risk for the development of ulcers -- six hours! If you feed only twice a day, and it takes the horse only 2-3 hours to clean up its feed (many will do so even sooner, depending on what is being fed), that horse is going 9-10 hours with no food. Is it any wonder that so many of our horses have ulcers?

It is also psychologically stressful for a horse not to have continual "chew time", and thus horses fed on a twice a day schedule demonstrate significantly higher rates of stereotypic behaviors -- also known as "stable vices". Cribbing, wood chewing, weaving and pacing are just some of the behaviors that are caused by a combination of the physical discomfort of hydrochloric acid eating away at the stomach lining, and the lack of natural amounts of chew time.

What causes the ulcers to form is twofold:

  1. Not enough saliva:  This happens because horses only secrete saliva when they are chewing (again, the opposite of humans, who secrete it most of the time), and the bicarbonate in the saliva serves to buffer the stomach acid. When you have very few hours of chew time, that means very few hours of saliva. Without any saliva coming in, the acid in the stomach is not buffered, and the acidity quickly increases.
  2. The lack of a protective barrier: Hay in the stomach forms a "hay ball" that prevents acid from splashing up onto the upper portion of the stomach, which is not designed for prolonged exposure to the acid. The stomach of a horse is quite small (only 4 gallons/15 liters on average), and it cannot hold a lot of food, so hay clears the stomach relatively quickly. Once the stomach is empty, there is nothing to act as a barrier.
If you feed grain in any significant amount, this will make the problem even worse, as grains form volatile fatty acids (VFAs) in the stomach, which alter the gut lining and make it even more vulnerable to erosion by hydrochloric acid.

There are other facts and studies I could throw around here, but you get the idea. So, what can you do about it if you don't have the ability to split your horse's feedings into multiple smaller meals a day? Two words for you: SLOW FEEDERS. Slow feeders are nets or feeders designed to only allow your horse to get a small mouthful of hay with each bite. They have to work at it, and thus it extends the time they spend eating. There are many, many slow feeders on the market, and some people build their own. I personally like the Nibblenet (choose the smaller hole sizes) and the Freedom Feeder nets, but to each his own. If you want more information on this WAY BETTER feeding strategy, Google "Paddock Paradise Slow Feeders" and you will find tons of useful information.

It is our responsibility to try to adapt our management practices to accommodate the horse's needs -- after all, they didn't ask to be domesticated. Thus, if you're feeding only twice a day, ask yourself if that is in the horse's best interests or yours.

P.S. I have an article coming out soon in EQUUS magazine on the concept of slow feeding...keep your eye out for it!  :  )

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