Considering we're talking about an average-to-good alfalfa hay, how much would you feel comfortable in feeding a 5 year old?
Many of you might have seen how complicated my horse's feeding management is and I was wondering if I could up the alfalfa hay and maybe cut back on some of the other stuff. Just don't know how much is too much.
I've fed plenty of horses free choice alfalfa with no problems. Granted it was usually to starved horses that were regaining their weight or harder keepers. Most of them have been TBs. Free choice alfalfa COULD make your horse hot if he's getting more calories than he gets exercise--not so much because of the hay type being alfalfa IMO, just because of the calories vs work load. I wouldn't feed a pony or easy keeper unlimited alfalfa, but a medium or hard keeper, I sure would. And then reduce their "hard" feed!
We used to feed all 8/9 of our horses straight alfalfa-20% of their weight on a good day and nearly free choice in severe weather conditions. We've never had a problem with it. That's all we fed them, then.
Now we live where the only hay is grass hay and the horses aren't doing nearly so well. We're having to supplement them for the first time ever.
I'm not sure about your situation or your feeding schedule. But my guy is fed 1 flake of alfalfa each night with 1 flake of brome. It's just how we've seen his feeding routine has worked the best for us.
Generally in a situation like yours 50:50 alfalfa to grass. However, before I switch the seniors over to a senior ration when their teeth are starting to go I switch them to straight very fine stem alfalfa. It helps keep their weights good and easier to chew. Not to mention keeps feeding senior costs down.
If your grass hay is low to ave quality I would likely be increasing the alfalfa if this was my horse...unless she/he lives off of air. I would be increasing alfalfa for sure before I increased grain or other feed for a horse that needed some weight.
I love feeding alfalfa and have fed it free choice to a few horses (like someone else said, either very hard keepers or very hard worker). I would prefer to feed my horse all or mostly alfalfa because he eats it better than the nice timothy I give him now.
I've yet to have a real issue with horses getting hot on it. Fat? Yes. But not hot.
To answer your question (and considering he has no digestive "issues"), as much as he can eat. From Nov-Mar, my horses get free choice alfalfa. April - October, when the pasture is lush, they don't get any hay (or grain, for that matter) unless they are kept in for a period of time for some reason (they are turned out and can come in/out as they please).
Right now, I have three on that regimen: a 17 yo air fern Paint gelding who gets a cup of oats, 1/4 lb., maybe?, 2x/day (so his feelings aren't hurt) and a 25 yo TB gelding and 30 yo TB mare who get 1.5 lb Triple Crown Senior 2x/day. The TB's are retired; the Paint is in moderate work. All three are in excellent weight (maybe a little too excellent!). I've owned the two geldings since they were youngsters and have always had them on this regimen.
Over the years, as I have cycled through a few horses, once I get the weight on the hard keepers (the current 30-yo TB mare is one), they do fine with this program. I've had a couple of horses come in showing every rib. They've left fat, shiny, and happy. I attribute it to one thing: good forage and plenty of it.
As some COTHer's signature line reads: More hay, less grain.
I have fed straight alfalfa to working horses with excellent results. Always paired it with a ration balancer to balance the ca : ph ratio. Important to do especially if you are feeding California alfalfa which can lead to enteroliths
Most ranches around here put out a big square bale of alfalfa in their working cowhorse pens and let them have at it.
Horses are worked regularly and do absolutely fine on it.
That is mature geldings, not horses under three or broodmares, that would need a bit more carefully balanced calcium/phosphorus ratio.
Protein level that is not high enough is a limiting factor to growth and maintenance.
Too much will be eliminated and so wasted, but without harm to a healthy horse, unless it is getting too fat.
Alfalfa needs a different kind of careful management than feeding itself, that is being sure it is clean, as it molds easier than other hay.
We hand feed two standard flakes per mature gelding twice per day, that come from two different cuttings.
They also have dormant grasses out in the pasture to just munch around during the day.
In blizzards and very, very cold weather, we may add to that.
In the summers, with green grass out there, they get one flake twice a day.
We have done that for years and all horses have looked great, according to our vets.
We generally don't feed any grain other than a handful as a treat to bring them into the barn for grooming, farrier work or riding.