Multivitamin with probiotic.

I really hope PeggySue chimes in here......
 
But I will say that most horses-unless there is an issue do not need a daily probio.  My vet recommed plain yogurt-the stuff with no sugar and that works great and is fairly cheap to use for 3-5 days at a time.

  There's no harm in adding a daily probiotic to the diet expecially in mature horses that have a less efficient digestive system.  Many senior feeds add a probiotic to their ratioin for this every reason.  If the horse has a good gut population and doesn't need supplementation, they are simply digested or eliminated. 
 
  The problem with probiotics are they are non regulated, have little to no testing behind then,  there is a huge variance in products, dosage, viablility, and the bottom line we don't know how much a horse needs.
 
  You should be feeding a separate vit/mineral and probiotic supplement.  (can't say I've ever seen a combination) Since the normal gut contains 25-40 major digestive enzymes, buy a product that isn't limited to one or two aids.  Change products.
 
  Diet and managment will have a greater impact on the incidence of colic than a probiotic will.  Good dental care, fine stem easy to chew hay, warm water and a review of all other feeds will help assure a touble free winter.  Also, get a tube of banamine paste from your vet just in case.

Thank you. So helpful. I am just worried about the winter now, due to the fact he coliced..and know that makes them more susceptible to it again. I added triple crown senior..and thinking of adding a small amount of oil..which oil is the safest to add? Vegetable oil or was it the Canola oil?

  TC adds a probiotic to all their feeds.  You'll probably add 1 B CFUs per 7-8# fed.  Skip adding more.  In human nutrition studies, the body does not differentiate between oils so it's my belief that neither does the horse.  What I have found is the canola will harden at a lower temp than the veg oil so if the feed room is cold, it might save you some grief by feeding the canola.  Adding extra oil is always safer than upping the feed.  2 C oil (1#) is equivalent in Calories to 3.3# senior feed or about 4.5# grass hay.  You can save some $$ on your feed bill when you used it wisely.

Sorry guys I am not on thsi forum alot...
 
in this case I would go with Triple Crown Senior it is grain free so less chance of it causing colic and has both Pre and Pro Bios added