The younger Kanavy, who won the title on Peirez four years ago in Kansas, dropped out after her 16-year-old grey gelding, Peirez, took a tumble two miles from the first veterinary checkpoint in the $300,000 (pounds 190,000) race.
No fewer than 174 riders set off at the crack of dawn at the Abu Dhabi town of Ghantoot and endured high temperatures as they steered their mounts along the 160km (99 mile) course.
"I am delighted to regain the world title, which also makes up a bit for the disappointments of my daughter on our favourite horse, Peirez," said the 52-year-old Kanavy.
Valerie and Danielle Kanavy have both won the world championship on Peirez before, and Valerie Kanavy's win maintains the American hold on the championship since the first competition in 1986.
Fausto Fioricci, a doctor from Italy, was the dark horse in the field, finishing second on Faris Jabar, another grey gelding, 50 metres behind Kanavy. Japan's Daisuke Yasunaga, who trained in Australia, finished third.
No official timings were released by the organisers. A computer failure meant riders were left without waiting periods for the next stages.
The Emirates, which expected its riders to be among the top three, had to be content with riders in fourth and fifth places.
Dubai's Crown Prince, Sheik Mohammed bin Rashid Al Maktoum, saw his hopes disappear when his horse, Nelson I, failed an examination at the fourth check point.
The sheik's eldest son, Sheik Rashid bin Mohammed, also had to retire.Reuse content