Section, acts June 25, 1948, ch. 645, 62 Stat. 759; May 24, 1949, ch. 139, § 29, 63 Stat. 94; Aug. 15, 1953, ch. 506, § 2(a), 67 Stat. 590, prohibited purchase of Indian-owned livestock subject to unpaid loans from Federal revolving fund or from tribal loan funds.