New Hay Caused Hives...

[AliciaH]

My horse, Roxie, has hives all up and down her neck and under her blanket a bit.

We were running out of our old alfalfa, which is 2-1/2 years old.  Brought home some new alfalfa and also some alfalfa/orchard grass mixed to start transitioning to grass.  Since the symptoms correlate to the introduction of the new supply, I'm 99% sure it's one of the two hays.  I fed the alfalfa/orchard mix yesterday morning and don't remember seeing any hives when I brought her in for the night.  I fed the new alfalfa for dinner, but I didn't check on her afterwards.My son fed her the mixed stuff again for breakfast this morning.  I found the hives today when I went to turn her out, so I don't know if they were there before he fed breakfast of after.  No, he wouldn't have noticed them.

For anyone that's had an issue like this, what would you suggest? 

I only have 2 flakes of the old stuff left.  Should I feed that for the next day?  But then I won't have any back up.

Should I just feed the new alfalfa and cut out the orchard grass since she's never had that before anyway and see what happens? 

Or because I noticed the hives today (after the first alfalfa was fed) and not yesterday after she'd just had the mix hay, should I maybe just feed that?

Or, maybe feed the old stuff tonight, then which one should I try in the morning?

In know, my bad for not getting the new stuff sooner and remembering to transition the whole lot.  I'm out of practice on this stuff.

[AllenF]

I have never heard of feed causing hives.   Give it a couple of days and see if it passes.

[AliciaH]

Allen, the vet called back.  Even he has feed allergies as 3rd on his list for the cause of hives in our area.  The first are gnats, the second is a contact allergy, like change in bedding.

In the case of gnats, he said to look for "crusties" under her belly and other delicate areas -- negative.  There has been no change of bedding, and the hives are restricted to her neck, which could have been in contact with something that bothered her, but they are not on her legs.  They are on her sides and withers, which are covered by her blanket, so if it is a contact reaction, complete contact doesn't seem to be necessary.  But there have been no new changes in her environment.  Bedding is the same, nothing new in her paddock.  I'm flumoxed. 

So, if not a food allergy, then it's a mystery.  The prescription is benedryl and I'll feed a flake of the old stuff tonight, just in case, and start again tomorrow.

[kathyp]

might not be the hay but something in the hay.  some dust or mold that you can't see, but she's reacting to.  had a friend who's horse had such bad allergies here, she sold her to a family in TX.  mare never had a problem down there.

when you do start a new hay, it's a good idea to mix it with the old and break them into it over the course of a few days.  sometimes the change messes up their systems.  it's not like they have really efficient digestive systems anyway!  

[oliver]

Possibly protien bumps, high protien hay usually along with grain can cause this in horses. remedy clean grass hay remove grain especially sweet feed..dl

[AliciaH]

Kathyp, interesting that your horse was fine once it moved south.  And, yes, I could kick myself for not acclimating her better to the feed.  Like I said, I do know this, I just forgot.  Not fair that she has to be incomfortable for my mistake.

oliver, thank you for explaining about the protien bumps.  That makes a lot of sense and was more along the line of what I thought the problem might be.  I'm keeping an eye on her and will work in that direction.  Thanks for the heads up about the grain.  She doesn't get much, just enough to mix her vitamins in (and last night, her benedryl).  But if it's exasperating the condition, I'll pull it for a few days.

Not that it couldn't be something else, but given that this was the only change in her life, I'm working under the basic principle that the easiest answer is probably the most obvious one. 

I gave her one of the two flakes of the old batch that I still have for dinner last night, then a very, very small flake of the new alfalfa for breakfast.  If the hives come up again (they were considerably better this morning but not gone entirely), I'll know that that's the one giving her fits.  I can repeat by giving the old stuff for dinner tonight and give her a small flake of the grass for breakfast tomorrow.

Thanks, all!

[kingbee]

I've always heard that too much protin was bad for horses.  Maybe its that new improved high protin alfalfa.  In Texas I suspect that allergic mare is now eating a lot of Coastal Bermuda hay now, not near so much protin.  The protin content of alfalfa hay can vary by quite a lot depending (in descending order)on whether it was cut just before the alfalfa started to bloom, while it was in bloom, or after it had finished blooming.