AMES ? Iowa cattle producers have a chance to support the Iowa Cattlemen?s Association through the Merck Animal Health ?Cartridges for Cash? program, formerly known as ?Wheels for Bucks.?The program now includes Revalor-XS (trenbolone acetate and estradiol), in addition to Ralgro (zeranol). The Iowa Cattlemen?s Foundation will receive $1 for every Revalor-XS cartridge and 50 cents for every Ralgro cartridge ...