Behavior change in horse eating lucerne

Question
We have a beautiful 5 year old off the track thoroughbred that has been going along beautifully in his retraining.  He is extremely quiet, co-operative and willing to learn.  Until we fed him lucerne hay.  It felt like he had a brain transplant.  He turned quite evil and was not happy at all and did everything to try and dismount his rider.   Needless to say, we no longer feed him lucerne.  It took a week before his behavior changed and what I was wanting to know was how long does it take to get out of their system and if there is anything that we can do to speed it up.  We want our sweet thing back and not the monster from hell. Also is this  a common side effect of lucerne hay?

Answer
Hi Anne!

I never like to attribute bad behavior in a horse to certain, ephemeral things...such as feed, hay, chiropractic issues and so on.

99% of the time, bad behavior sneaks up on a rider because they are not paying close attention to the signals.  Things can slide so imperceptibly that before you know it you are on the ground and haven't a clue why.

It is typical that at one point in the training the horse rebels.  Too much too fast is usually the reason.

But, you have asked only about lucerne hay, so I will only address that.  You have a hot blooded horse and you gave him a hay that can be as much as 20% protein, not to mention his regular feed too.  You may have also over fed him the hay and really jacked up his energy levels.

I cannot say when you will have all the effects out of his system.  You would need to consult your vet on that.  While you feel he still exhibiting his "high" just exercise him more.... out of the saddle.  Longe him for 15 min in full tack at all 3 gaits prior to every ride.  Make turnout a priority and put him out with another buddy horse who wants to run too.  

If you were feeding him this hay to help with his weight (as TB's are naturally hard keepers) try a stabilized rice bran top off that is high in fat, not in protein.  I also like a beet pulp mash.

Maybe the hay made him bad and maybe not.  Before you decide just where the impetus was for this, really watch him in his training and see if he did hit a mental or physical wall and that started it.  Or is could simply be the rider.  You did not say who that was but, never count out pilot error.  A trainer needs to be a mother, a father, a saint, a psychiatrist, a mind reader and always smarter than the horse!

Good luck and remember to always wear an ASTM/SEI approved helmet!

Solange