Hay

All I can tell you is what's in my area (near Memphis).  You do NOT want cow hay.  I really like to look and smell....  I guess if a horse was starving, cow hay would be better than nothing...

Cow hay usually means hay that should not be fed to horses because of the type of hay...or it has weeds...it's old...moldy...been rained on...etc... That's why it is cheaper.

  Depending upon where you live, cow and horse hay can have very different meanings.  Cow hay could refere to weedy hay, new first seeding hay, outside, top or bottom bales or discolored weathered hay. All fine for normal horses.  It could be varieties that aren't typically fed to horses (barley, wheat, oat) but they will eat with no problems or it could be sudex or triticale that they shouldn't eat.  It can be hay that was lightly rained on in the windrows.  As long as it's dried correctly, it's fine for horse feed.  It can be over mature low nutrient dense hay (good as it's low in sugars for matue easy keepers)  It could also mean simply the way it's put up in either rounds, 3x3s or dairy squares.
 
  Cow hay can also mean moldy, dusty, low quality, slimey, stemmy questionable hay that could make a horse very sick or kill them. 
  
  If you're having trouble finding decent quality affordable hay, first look into buying 3x3s or larger bales if you can figure out how to handle them.  Most smallish tractors with a bucket can handle a 700# 3x3.  You can also just chain them up and yank them off the trailer with another truck.  Your hay doesn't have to be bright green.  Hay that is lightly rained on is very often overlooked by horseowners and farmers can only sell it to cattle operators at a lower cost eventhough nutritionally it is fine for horses.  If you live where one variety of grass hay, say timothy, is the predonimant forage choice, look at other types of hay (alfalfa, fescue, oat, barley, bermuda, wheatgrass....)  Compare apples to apples when hay shopping.  Figure out what the hay costs per ton.  Often times that $4 bale is actually more expensive than the $6 one.

All good advice, but I have to disagree about one thing -- sudax is wonderful feed for horses! Most people think of it as cow hay and won't feed it to horses, but I've been feeding it for 40 years. My horses are so spoiled by the sudax, they won't touch most varieties of grass hay.

  That's because I should of typed Sudan grass.  It can lead to prussic acid poisioning and death.

Sudax is a hybrid sudangrass/sorghum. We raised common sudangrass for many years. You're absolutely right about the prussic acid -- however, that only applies when it's green and growing. NEVER graze horses on sudangrass (or sudax) fields. But cut and baled for hay, it's perfectly fine.
 
I've winter grazed the horses on sudax stubble, and that works fine too.

Oh that's true that my horse dosen't touch most of grass hay.
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Earl Nunes