it is memorial day, and my brother just left. this day means something, but it makes me sad too. So this question kinda takes my mind off it. So I shall write of my own experiences and thoughts.
First it is helpful if folks define what is meant by work. This term is used often and without definition it can lead to confusion.
my work right now consists of gathering in corrals to put out on hill, and regathering- only if necessary at dusk. also we are shearing right now. which requires a dog to turn himself off and rest in shade when not needed. my cattle work is just putting out in morning and gathering at dusk, feed is lush and thick so my work is not hard or all day now. in fall this will change. I am a full time rancher.
in my own dogs, the fizzy sort does wear out quicker but they may learn to conserve by the hours of the work day and a bit of age.
A tense dog that hold their mouth closed will not be able to pant well to dissipate heat. I don't breed those.
i have a couple slick haired that are great in heat and a couple that are not.
i have a couple long haired that are good in heat and a couple that are not.
If they are not good in heat I don't breed them.
my best dogs on hot days seem to know just how much energy to expend. they do not flop back and forth but move stock by line power. they pant with mouths well open, and they have big mouths and large tongues. they use shade, water and rest when they can without me saying anything. and this is bred in. the flop i can control, but on a hard day where we are out for hours i cannot see the dog. if a dog wears out i would be forced to carry him home on my horse.
so any dog at risk of this i do not use for that work, and i do not breed from.
my best dogs on hot days also have hard, tough, feet. because in dry country on rocks if you have a days work soft feet won't do.
I have a dog that must move stock by movement rather than walk in power and that beauty of beauties- presence- this dog works a lot harder than my other dogs that have power and presence. so that first one can over heat quicker.
calm, power, big tongues, tough feet. (BtW I am outcrossing right now. )
now lets also at some point talk about cold.