Labs Lack of Energy

Question
Hi, I play catch with my 3 year old lab every day and he can usually play for about 45 minutes before tuckering out.  Lately I've noticed a drop in his energy level.  It seems like his energy span is getting shorter and shorter.  20 minutes and he tries to lay down lately.  He also seems very thirsty when we get back in. I've tried giving him water during play time but he is too obsessed with his ball.  We can't afford to just run to the vet at this time.  Does anyone have any ideas what it could be??

Answer
He could just be maturing and settling down a little.  Has his weight crept up?  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

I would keep an eye on things.  If he gets worse, you have to go to the vet.