CREDIT CONSTRAINTS, FARM CHARACTERISTICS, AND THE FARM ECONOMY: DIFFERENTIAL IMPACTS ON FEEDER CATTLE AND BEEF COW INVENTORIES：文章中分为饲养牛和肉牛，这两个概念该如何理解？ 同样的问题：cattle cacyles:is there a role for a financial accelerator,该文提到肉牛和替代小母牛，如何理解？