long term antibiotics and probiotics?

["guest@endurance.net" <guest@endurance.net>]

Nina Vasiliev rides4fun@hotmail.com
Hello everyone, 

First some background...

My horse was kicked during turnout, got a deep bloody wound on
 his knee which the vet cared for that day.  He was on
 antibiotics for 3 days, and stall rest until it closed up well,
 over 2 weeks.  Then lightly ridden twice, then back to turnout
 for 3 days,(with a different horse.) 

Well, his knee started to swell a little, it was warm and he
 started to limp.  Had the vet out immediatly again, and x-rayed
 his knee.  A piece of the periosteum,(the thin membrane coating
 the bone, had been torn away and there was an infection
 underneath. Ramere needs surgery to clean out the infection,
 then he will be put back on "longterm" antibiotics, altho at
 this point I don't know how long that will be...

Now to my question.  

If I need to give him antibiotics twice a day, can I also slip
 in some probiotics to help his gut flora?

If so how do I time that?  Or should I wait until we're done 
with the antibiotics?  Keep in mind that I board Ramere and I
 work...I'm a bit confused as to how to handle this.  Any
 suggestions would be appreciated.

Thanks,

Nina