By the 18th century, the breeding of mules had become a flourishing industry in Spain, Italy, and France. For many years the French Province of Poitou was the primary European breeding center, with some 500,000 mules bred each year. Heavier draft mules were demanded for farm work and a local breed of stud donkey became most popular. Soon, Spain was at the forefront of the mule-breeding industry as Catalonia and Andalusia each developed a larger and stronger breed of donkey.