SOY FLOUR AS A SOURCE OF PROTEIN FOR BABY PIGS 1

SUMMARY Soy flour as a source of protein for piglets 3 weeks of age has been investigated under carefully controlled conditions by feeding liquid soy flour diets, hourly, with the aid of an automatic feeding device (Autosow). The aver- age daily gains and dietary efficiencies that have been observed in these experiments were ob- tained with diets that were free of antibiotics. Average daily gains (kilograms) and dietary efficiencies (kilogram dry matter per kilogram gain) were .37 and 1.40 (untreated soy diet, 25 % protein calories);. 39 and 1.50 (acid-treat- ed soy diet, 25% protein calories); and .37 and 1.15 (non-fat milk solids, 25% protein calories). Experiments comparing different soy flour diets containing 15% and 25% calories (isoca- loric) showed that there was no difference in the daily rates of gain (.34 and .35 kilo- gram/day, respectively) and efficiency of utili- zation (1.36 vs 1.37 kilogram diet/kilogram gain, respectively) in these two diets. Further experiments designed to determine the mini- mum concentration of protein required to promote growth rates comparable to the 15% protein caloric diets used soy flour diets con- taining 15%, 11% and 7% soy protein calories; the average daily gains (kilograms) for these diets were .43, .44 and .31, respectively. The dietary efficiencies were 1.32, 1.35 and 1.90, respectively. These data show that a diet containing 11% of the total calories as soy flour protein is sufficient protein calories for pigs 3 weeks of age and reared under the conditions in which an automatic feeding device is employed.