Occupying about 40 million hectares (99 million acres) of pasture, livestock farming, especially cattle breeding has long been an important Colombian industry. Of this total area, about 19 million hectares (46.9 million acres) are actually used for livestock production. The Ministry of Agriculture maintains experimental stations in Antioquia and Bolívar departments to improve breeds, but the quality of livestock is still low. Cattle are driven to market by truck. This practice often entails crossing high mountains, with much wastage; accordingly, there has been a movement to construct slaughterhouses and meat-packing plants near the ranges. Dairy farming, not important in the past, expanded in the 1970s, especially near the big cities. Colombian sheep produce about one-third of the wool used by the country's textile industry. The government maintains an experimental station for sheep in Cundinamarca and for goats in Norte de Santander. In 2001 there were 26.3 million cattle, 2.3 million sheep, and 2.2 million pigs. The production of beef and veal increased from a 1989–91 average of 713,000 tons a year to 746,000 tons in 2001.