Horse REFUSES to eat grass, but will eat Alfalfa

Question
Hi Jessica,  My horse is coming 5 this year and as far as I know has been fed
grass his whole life (mostly grazing in the pasture).  However, my girlfriend
feeds her horses alfalfa, so I started giving my horse a flake or so after
working him. After a couple times (maybe even the first), he then refused to
eat his grass hay and seemed like he was always looking for the alfalfa.  So,
after a couple nights of giving him alfalfa and realizing he wasn't eating
grass, I stopped giving him the alfalfa flake.  It took him a week or so to get
back his appetite for grass (which means he ended up losing some pounds--
more than I prefer) which even now (3 months later) he doesn't usually eat in
the morning, just seems to eat at night.  I understand that was a little
complicated, but have you ever heard of something like this happening?  Is he
just tired of grass and wants to switch to alfalfa?  I had just never heard of a
horse starving himself just because he wants alfalfa.  What should I do to
remedy this?  I can feed him alfalfa for a while, but come May I will be putting
him out to pasture where there is only grass.  I understand that alfalfa is
better for him with better nutrients and protein, but I hate how he just refuses
to eat grass.  Is this just a phase?  Thanks in advance for any help you can
give.  

Jonathan

PS, he is also on rolled oats in the evening

Answer
Hi Jonathan,  I don't know if you are talking about him not eating grass or grass hay.  If he's stopped eating the grass hay then that's understandable.  Alfalfa hay is like candy compared to just fescue grass hay.  I've seen many horses not eat their grass hay if they have the choice to eat alfalfa.  It will take a while for your horse to want to eat the grass hay again but he should start eating it within a couple of days of going without the alfalfa.  Unless you just have a very demanding horse who may be a picky eater (which it sounds like you do.)  If he's not grazing in the pasture eating fresh grass then I would be a little curious.  I've never seen a horse that would only eat alfalfa hay and not fresh grass.  If he's standing all day in the pasture and not eating grass then I would think about consulting my vet.  Either way I would stick to one or the other, that way he doesn't pull this stunt again.  You can also get some dried beet pulp for him to add to his grain if he's still losing weight because of the hay change.  If so, be sure to soak the beet pulp at least an hour before you feed it.  I usually feed 3-4 quarts per feeding.  This will just help replace the fiber he's not getting by being picky with his hay, and help keep his weight on during the transition.  Good luck!  Jessica