The Value of Thiouracil in Rations for Growing and Fattening Pigs

ASTWOOD (1943) showed that the formation of thyroxine by thethyroid gland can be inhibited by the administration of thioureaand related compounds. The increase of daily gain in weight of the thyroidectomizedsteers as reported by Andrews and Bullard (1940) of the PurdueStation indicate that these compounds might be useful for fattening pigs.Preliminary tests at the Cornell Station showed that thiourea, fed at therate of 0.379 grams daily, was unpalatable for fattening lambs, so thiouracil, 3a similar product, reported to be less soluble in water than thiourea, wasused in the tests with pigs. Turner et al. (1944) at Missouri also have reportedthat pigs dislike thiourea. Data and Discussion First Experiment Three lots of nine pigs each, with an average initial weight of 124 pounds,were self-fed in dry lot from November 1945 until an average final weightof zoo pounds was reached. The pigs in lot I were self-fed a basal rationconsisting of 58 pounds of ground yellow corn, 25 pounds of wheat flourmiddlings, 6 pounds of meat scraps (55 percent protein), io pounds ofground alfalfa hay, and 0.5 pounds each of iodized salt and ground limestone.The pigs in lot II were self-fed the same basal ration plus 0.1 percent thiouracil,and in lot III the basal ration plus 0.2 percent thiouracil (table 1).