Pasture Feeding

Question
Hi, I have a 13 yr old that is an easy keeper.  By that I mean he puts on weight easily.  He was gorgeous in April but now looks like a pregnant mare.   I have 3 other horses. I paddock them at night, no grass.  In the day they have pasture grass.  About split, 50 on, 50 off pasture. How do I keep his weight down?  Is it okay to repeat keeping them in the paddock all day with only hay and then next day pasture, then paddock, etc.  Or will this cause stomach, laminitis issues?  I'm trying to figure out how to keep his weight off.  I'm not a hard rider, more leisurely.
Thanks,
Mary Beth

Answer
Mary,

I can think of a couple of things behind his weight gain.  Given his age I would have him tested for hypothyroidism.  If he's the only one who has turned into a butterball on this regimen then I suspect he's got a metabolic issue here.  Hay will generally put weight on horses too if enough of it is fed.  Easy keepers on free-choice hay will do very well; ponies are perfect examples of this.  Alternating days of hay with days on the pasture won't hurt him in any way but isn't really the answer.  If he comes back OK on thyroid levels then invest in a grazing muzzle.  It will limit the amount of grass he can consume while allowing him the socialization time and exercise value of the pasture.  Take the muzzle off at night when he's in the paddock and just put it on when he's out on pasture.  Stop feeding him any grain - just a little handful when the others get grain to keep him happy - and try to exercise him more.  If all he needs is to reduce his calories then the weight will gradually come off.  But please, get him tested.  He's in the age bracket when horses can start developing problems - Cushings syndrome is another one - and you really don't want to have anything like that be the underlying issue with his weight gain.  I assume that this hasn't happened in prior years so something is going on to cause this this year.  

Lyn