Re: propionic acid

[Susan Evans Garlinghouse <suendavid@worldnet.att.net>]

Cameron Wood wrote:
  He mentioned that all of
>  his hay was treated at baling time with propionic acid, to "keep the hay
>  from fermenting" in the mow. 
>     My question is.... what is propionic acid, and should I be concerned
>  about feeding this to my horses?  The farmer assured me that propionic acid
>  is a normal component in a horse's digestive system and there's no problem
>  feeding it.  Should I buy it?  Any thoughts? Thanks!

Hi Shannon,

Yes, propionic acid is one of the several volatile fatty acids produced
in the equine cecum and colon as the result of microbial fermentation. 
The process of treating hay as you described is fairly common and very
useful and absolutely harmless to the horse.  Several different types of
product, like lactic acid or bacterial cultures are also used, but
propionic works the best.  If done correctly, hay can be nicely
preserved at a relatively high moisture content without molding or
spoiling.  If done wrong, it'll still mold.  However, since you broke
open a bale and checked for heat and mold, it sounds like your supplier
knows what he's doing.  Acid-treated hay is especially nice for horses
with upper respiratory problems, as the hay is juicier and less dusty,
so they can eat it better.

Some people get alarmed over the very idea of their horse's hay being
treated with acid, but it's absolutely no different from a cucumber
being treated with acetic acid to make pickles.  It's not corrosive,
it's not dangerous, it's not "unnatural".  It's just using brains and a
little natural chemistry to solve a serious problem (mold) in producing
hay.

Because the hay doesn't get as much sun-curing, the vitamin D content
tends to be slightly lower (though not enough to be a concern) and
acid-treated hays tend to oxidize a bit quicker, so the beta-carotene
and vitamin E content declines a little faster.  Again, not enough to be
a concern.

Occasionally, the palatability is a little lower with acid-treated hays;
horses will preferentially eat a non-treated hay over an acid-treated
hay, but if they don't have the choice, they happily munch down the
acid-treated hay in the same amounts as they would non-treated hay.

So, bottom line is if it looks like good hay, grab it.  Being
acid-treated is not at all a concern for horses and really good hay like
that is a real treasure.  Wish I had access to some!

Good luck!

Susan G