Years ago, before testing, and before there had been NEARLY as much discovered about the genetics of paint/pinto coloring, I bred my daughter's visible frame(I now suspect she was also sabino, and possibly, splash, as she had one blue eye, lots of 'laceyness' around the edging of her white, an apron face,etc.-we had shown to to become a PtHA Champion)-to a nice area stallion, belonging to an longtime acquaintance just down the road from me here, who appeared to be a tobiano(I did know one shouldn't breed what we then just called 'overo'-meaning frame-to 'overo'.) I then sent the mare down to an old friend in Socorro, where we had moved up here from, because she had fulltime pasture/turnout room. The mare foaled on Easter Sunday; I got a call from Pat saying she couldn't find any color on him...I drove down--had a lovely big colt, but no color. He seemed healthy and vigorous, nursing enthusiastically. However, he never passed any meconium. We watched him all day; by late afternoon, he was showing signs of noticable pain. The only local equine-capable vet lived just up the lane from Pat, actually came by about then(with info about the Girl Scout cookies one of her kids was selling, or some such thing-VERY fortuituous, as her-then husband was a nutcase who would literally threaten people with a gun if they came around when he 'thought' Terri shouldn't be 'bothered'-we wouldn't have DARED to call her, or go by her house/office, on that holiday day!)....anyway, we told her the situation, and requested she come back and euthanize the colt-which she did. We left him with the mare, in Pat's round pen, overnight-I stayed overnight, too, and Terri(the vet)came back the next AM and did a necropsy. Sure enough, his digestive system ended in a little thin 'channel' about the size of a soda straw-NO WAY would anything ever have passed through it. These were full-sized, registered Pinto/Paint horses. The sire was in truth a tovero, but basically, looked tobiano-in fact, he sired a second lethal white that same year! The stallion's owner NEVER acknowledged that, ever, nor offered any recompense of any sort(of course, I wouldn't have rebred the mare to him!!) It was a heartrending experience, for sure-one I would never wish to have to repeat!
I don't have much contact with the Paint horse community nowadays, even though I still own an APHA mare for riding-if you don't show, the club isn't very interested in you-and I haven't shown the 'bigs' since 'peanut rolling' and other noxious practices got well-established...but I do think it is probably correct to say that many, if not most ,aren't 'into' the genetic testing they SHOULD be doing to prevent such sad occurances. I know I WOULD be so doing, were I still breeding!!