The drought of Triple Crown winners that reached 34 years when I’ll Have Another scratched Friday from Saturday’s Belmont Stakes and retired because of a tendon injury, has nothing to do with either bad luck or mysterious curses.

It has everything to do with a wrong-headed, quick-fix culture that has overtaken the American thoroughbred scene, according to an expert on bloodlines.

The use of drugs, both legal and illegal, and the obsession with speed at the expense of stamina have combined to dilute the quality of American thoroughbreds, according to Lauren Stich, columnist for gradeoneracing.com and author of Pedigree Handicapping.

I’ll Have Another’s pedigree, rich with males with good stamina, led Stich to pick him to win the Triple Crown, and she thought Union Rags would be the strongest contender. But she did wonder if running three races in a five-week span would be too much for any of today’s horses.

Stich explained that horses get their stamina and surface (turf or dirt) traits from the males in the bloodline, starting with the sire (father), the maternal grandfather the and dam sire (father-in-law). The class of the horse — anywhere from a claiming horse to a stakes-grade horse — comes from the females.

During a conversation with Stich last week, a couple of days before I’ll Have Another scratched, she explained why today’s American thoroughbreds don’t rank with those of decades ago.

Lasix, a potent diuretic given to horses to stop bleeding in the lungs (aka exercise-induced pulmonary hemorrhage), lengthens the recovery time for the horse.

“Before the ’70s, Lasix wasn’t used,” Stich said. “If a horse bled, it was retired or culled, so they didn’t have this (trait) on the breed,” she said. “Now they’re breeding back to horses that were unsound. Horses were healthy or they didn’t run. They’re breeding back to unsoundness, instead of trying to get rid of the trait.”

Back in the day when pitchers went nine innings routinely, only the strongest, healthiest thoroughbreds were bred, which strengthened a line that since has been diluted.

“And now, everyone breeds for speed,” Stich said, explaining they want to make money off of them instantly on the shorter yearling races. “In Europe, they don’t allow medication, and they’re breeding for speed and stamina. The owners and the trainers don’t want to see it, and even the media here won’t write about it, but we are the laughingstock of the thoroughbred world.”

Those horses run almost exclusively on turf, and the Triple Crown races all are on dirt, so transporting horses from elsewhere in the world to jazz up the big three races isn’t as simple as it sounds.