How long does bute take to work?

Think Nat's right. Generally it is one morning and one evening. So, max 12 hours.
 
It depends how it was administered. Orally, it starts to take effect within the hour but the effects are not usually most noticeable until the horse has been on a steady dose for a few days.
It's still detectable for a while in bloods and urine though, so watch out for that if you compete.
 
Thank you. As it happens its not for a horse. Its for a sheep.
I was advised some time ago that you can give it to a sick sheep for pain relief, only a third of a sachet at a time though.
I have a ram who went down a couple of weeks ago. Suspected stroke. Havent the heart to have him put to sleep yet. Just giving him time to recover if possible. Gave him some bute last night so was wondering if the effects may have warn off by now. He has made some improvement over the last couple of weeks but I fear its not going to be enough.
 
newrider.com