>>11222013They don't actually faint. It's caused by a dysfunction of a chloride channel in their muscles. Basically, it takes longer for their muscles to relax after an involuntary action. Their legs stiffen, and they fall over.
As for how it happened, it turns out that the same dysfunction that causes "fainting" means they can't jump as high.
>"Hey, these goats don't try to jump over our fences. Let's breed the FUCK out of 'em!" 
