A friend of mine is Chinese... and a very cheap drunk.
A sip of beer makes him flush beet-red. After half a beer, he is on the dance floor flopping around like Iggy Pop having a seizure. If he ever drank two beers - something he would never do - I'm pretty sure he'd look like Jacky Chan on a meth binge for about 5 minutes then fall into a coma.
He can get drunk just by watching a beer commercial mainly because of his genes. He is from an an ethnic group (East Asian) that has low levels of the liver enzyme that breaks down alcohol. And over the weekend, the reason my buddy's Longhaired Weimaraner named Zeiss did not get a prize one in his UT test is probably also because of his genes: he lacks the ability to function well in the heat.
Uma, our Ponto is the same. As soon as it gets to T-shirt temps outside, forget even trying to run her for more than 10 minutes. The build, coat, and genetic predisposition just will not allow it. Of course when the temps dip to hat-and-scarf territory, watch out. Both Zeiss and Uma will go all day, every day.
So during the field search portion of his test, Zeiss covered the ground at a gallop for about the first 15 minutes or so. But it was 86 degrees that day and with the humidity it probably felt like he was running on the surface of the planet Mercury.
In a fur coat.
By the 20 minute mark Zeiss was trotting. At 25 minutes he was no longer reaching out. By the time the judges called "time" he was practically at heel, tongue dragging on the ground. Despite his handler pouring water on his head, he simply could not shed enough heat to keep going. Its a good thing he is a sensible dog. He slowed down to avoid burning up completely. Henri is just too dumb right now to ease off the gas when he starts to overheat. Last year he took off after a deer on a hot day and came back wobbly and disoriented. Good thing there was a cool creek nearby to soak him in. He was fine, but it scared the bejeebus out of me.
I have heard that low heat tolerance is a Weim thing. Certainly none of mine are very good in high temps. They much prefer a little frost on the pumpkin as it were. But I think most other breeds share the same traits. In 2003 in South Dakota, on a very hot opening day an estimated 100 (yes one hundred) hunting dogs of all kinds of breeds actually DIED of heat stroke!
The heat exhaustion from the field must have carried over to Zeiss's duck search. From all reports he looked like he was trying his best, slogging through thick mud and reeds but about half way through he just did not have the energy left to put on a prize one performance.
But he did pass the test! He earned a prize III and the respect of those who where there watching him run under the hot sun wearing a double layered fur coat!