The work presented in this bulletin is the result of the cooperative feeding experiments conducted on the Brookmont Farms, property of A. E. Cook, Odebolt, Iowa, under the supervision of the Animal Husbandry Section of the Iowa Experiment Station.

Three distinct lines of investigation were conducted: the first being a test to determine the relative economy of feeding light, medium, and heavy grain rations in beef production. The second was a test to determine the comparative value of Western and Northern steers in comparison with those from the Southern states for feeding purposes under Iowa conditions. The third was a continuation of the work commenced in 1902, reported in Bulletin 66 of this station relating to the feeding value of the various supplemental feed stuffs and condimental foods or stock foods, when fed in conjunction with com for beef production. In this test no stock foods were used, as the manufacturers of the same refused to enter a second test on the same basis as was accorded them in 1902 and the manufacturers of the supplemental feed stuffs. Mr. Cook furnished the cattle, the corn and the roughage fed. He also furnished all the labor needed in addition to Mr. Newton C. Rew, a graduate student of the Animal Husbandry Department of the Iowa State College, who had direct charge o f all the feeding, and to whom we are deeply indebted for the careful and accurate manner in which he dispatched every detail of the work.