Animal Science Department


Date of this Version



Published in JOURNAL OF ANIMAL SCIENCE 60 (1985), pp. 487-494. Copyright © 1985 American Society of Animal Science. Used by permission.


A metabolism experiment and two growth experiments were conducted to determine if threonine and isoleucine are the third and fourth limiting amino acids in corn for growing swine. In each experiment there were four dietary treatments. The basal diet contained corn fortified with minerals, vitamins, lysine and tryptophan. Threonine additions of 0 or .17% and isoleucine additions of 0 or .22% of the diet were evaluated in a 2 • 2 factorial arrangement of treatments. The addition of threonine reduced (P<.001) the daily urinary excretion of urea N and total N. There was a tendency for urea N excretion to be reduced further when isoleucine was added in combination with threonine.