Whats wrong with Corn?

If I remember correctly corn is pretty high in sugar.
I was also yelled at by a vet student when I mentioned my uncle feeds his horses corn on the cob as treats... she went off on me about how he's going to make his horses founder and whatnot... I stopped listening because her reaction to my innocuous little anecdote was very extreme.  (I tend to shut down when people scream at me and I don't feel like I deserved to be screamed at)  Besides, what was I going to do?  Tell my uncle who's had horses for more years than I've been alive that he needs to stop feeding corn because some vet student said so?  His horses never had problems.
Reidar only gets a tiny bit of corn as treat and only very occasionally (he's an air fern and doesn't need the calories).  But, the other horses at the barn get corn pretty regularly and they all seem to be in great health.

Hi,

Good question! Corn is higher in sugars & starch than most other grains, and is also harder for a horse to digest when dried, either whole or cracked. I haven't read of, but would imagine digestion of fresh corn would be likely digested quite well, and if it were small & occasional quantities, such as for treats, it would be unlikely to cause issues, unless the horse were IR or Cushings or such. Horse's digestive systems don't cope very well with sugar/starch generally. I would say that processed, corn isn't any worse than any other cereal grain, but is richer, so less would be needed. Corn oil is fine, pretty similar to other oils.

Brood mares, growing horses, athletes in heavy training, for eg, may benefit from added carbs, but it is not appropriate or necessary for most horses, and what for some will be fine, for many is not. Eg. carbs don't help much with heat production(low grade roughage digestion is best for that) so is largely inappropriate in winter. Depends also on the horse, lifestyle, characteristics of the grain & starch, way & amount it's fed(eg. small, frequent meals better than large, infrequent).

In recent years there has been a lot of study done into equine digestion, nutrition and also the effects of these factors on their feet. It has basically been found that feeds high in sugar & starch are largely problematic for horses. In addition, unprocessed cereal grains(with the exception of oats, which are more easily digested in the stomach) pass largely undigested through the stomach into the hind gut, where they effectively cause a massive sugar hit, leading to big lactic acid production from the bacteria & low pH(hind gut acidosis). This is a huge cause of laminitis and colic. So it's not just corn, but many traditional feeds & feeding practices are being examined & found to be not as great as we'd like to think. Such as lush, improved pasture, for eg... great for fattening cattle, not so great for healthy horses.

It has also been recognised by many in recent years just how common laminitis is. I would say in my experience as a hoof care practitioner, as well as my studies, that horses without lami are a far rarer beast than those with it. It still largely goes undiagnosed, at least until such time that it causes lameness & progresses to founder. As hind gut acidosis caused by too rich fees is the major cause, I don't like to chance it and advise people to avoid grains & sweet feeds wherever possible, and if feeding them, ensure good feed practices, such as feeding rations in many very small meals daily, with lots of roughage, for eg.

So no, I wouldn't say it's *necessarily* a bad feed, but potentially more problematic than others, so I would always opt for a safer source of carbs if it were necessary where possible.

The way I understand it, some corn is ok but not a lot.  When I "feed" corn it would be approximately the equivalent of 1/16 - 1/8 of an ice cream bucket...since I only feed 1/4 of the bucket once a day to each horse.  Less than 1/2 of that 1/4 bucket would be corn.
 
We fed this amount to 4 horses for years...and they never had hoof problems.  I have never fed more than a quart of any feed to my current horses and usually that is split in 1/2 also since they share the grain or I feed them separate.  (the pony will go to "her" feed station and wait for me there - I don't think she likes to share but they do without any grief)
 
So for 15 + years we fed them corn without any ill side effects.  Not to put down the expertise of hoof care professionals, but we could ride on gravel roads all day long, barefoot.

  The problem with corn on the cob, deer corn, is the presences of aflatoxins.  If the corn was produced under stress, stored under hot and humid conditions or has too high a moisture content, it will have higher levels of aflatoxins.  Why take changes when other forms of corn have lower levels?  Feeding corn does not produce a heating effect.  Corn is digested mostly in the small intestine.  A horses produces body heat in the fermentation process of long fibers in the hindgut.  That's where the advice to feed more hay and BP in the winter comes from.  Adding corn in the winter will add calories to the diet but it does not keep them toasty warm at night.  Corn can be problematic to laminitic and IR horses due to it's high startch levels.
 
  Corn does often have a bad feed reputation but it has more to being used improperly or on the wrong horses.
 
  Vitamins are not reponsible for muscle building, amino acids are.  Corn's AA profile pretty much mirrors that of everything else horses are fed so it doesn't have any special properties that can't be obtained elsewhere.