My 2 year old GSP doesnt seem to have the energy he had last year, i keep him in great shape with regular training and exersize at least 5 days a week, the only things i have changed are i got him cut and switched food to Diamond all natural extreme athelete food. The dog starts out fine but after a couple of hours has lost most of his range and is wiped out, it has been hot here, mostly above 80 and we have been out every day, anywere from 2 hours to all day. I keep the dog well watered in the field. Last year an 8 hour day was no problem. any advice would hepl. Thanks, EEk