(Bloomberg) — In the heart of U.S. cattle country, a four-year drought got so bad that Jim Sartwelle's east Texas ranches looked more like dirt parking lots than pastures. At one point, to keep the animals fed, he bought two truckloads of grass cut from the side of a road in Louisiana, about 200 miles away.

All that changed when the rains starting arriving in March and kept falling. May was the state's wettest month on record, and now there is more green grass than the cattle can eat. With the drought over, ranchers like Sartwelle are preparing to expand U.S. herds that had shrunk to the smallest since 1952 and sent beef prices surging to records.

The grass is "knee- to belly-high everywhere you look," said Sartwelle, 44. The fourth-generation rancher manages a 100-cow breeding herd with his father in Robinson and Sealy, Texas, that is down 20% since 2010. Now, with cattle prices high, Sartwelle wants to get his herd to where it was before the drought. "It's time to start building numbers back," he said.