Our 7 month old Yellow Lab is coming along fine. She eats well, plenty of water and excercise and the vet says she's healthy. Its going to be 105 here today so this mornings training session ended after 10 minutes of retrieving bumpers and a goose wing in the yard ( no water retrieves ). Like many of you have stated, I left her "wanting more" and we ended on a good note. Anyway, when its warm out ( 85 to 105 ), she pants quite easily and seems intolerant to any sort of heat. She's in her prime, why would she get so hot so easily, particularly after simple work-out / retrieving ? Maybe its just me ( and by no means am I working her til she collapses or gets disoriented) , it just seems like her tongue gets to hanging a little to quickly. Thing is, if I'm messing around in the garage with the door open, she'll go lay in the sun in the grass or even on the warm concrete driveway. My other question : My daughter gave me a simple plastic whistle with a pea inside. I prefer blowing this whistle vs. the metal one I have. The dog listens well to it. Two days ago, I got a Fox40 ( thing is loud !). The dog doesnt seem to listen to it, or at least as readily to it. Should I stay with what she's used to ( plastic pea whistle ), move strictly to the Fox40 til she gets used to it, or should I use the old one and use the Fox40 only when needed / windy ?...in other words, can I inter-mingle whistles, as needed, or will the pitch difference confuse her ?