sick doggy

Question
My lab just had surgery yesterday.  He was attacked by another dog and lost a huge tooth in the process.  He's supposed to eat canned food for 10 days.  How much should he get?  We have another lab, and they're competitive for food, so he will eat as much as I put down.  I don't want to give him too much, but I don't want the poor guy to go hungry!

Thanks

Answer
Give him about the same or a little more.  If he was getting 3 cups of dry, give 3 cups of canned.  If you want, you could check the calories of each and match them.  Often that isn't on the package.  You need to check th website or call customer service.  

You could also see how he does.  Matching what you are doing is only important if he is in good condition.   Your dog definitely should be narrower at the waist than the hips and chest. You should be able to easily feel the ribs, but not see them. Each dog is different. Standard recommendations are a good place to start, but each dog must have its food and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx