RESPOSTA DE NOVILHOS NELORADOS À SUPLEMENTAÇÃO MINERAL

A study to verify the possible mineral deficiencies in Nobre steers grazing a pasturo of guineagrass (Pan/cum maxiinum Jacq.) was conducted in the southeastern part of the state of Mato Grosso do Sul, Brazil. The study iasted for 336 days and used 200 steers in thefolbowing treatments: A) NaC1 + P + microeiements; B) Commerciai mixture; C) NaCI + P; and Dl NaC1. Many animais in treatment C and D began to loose weight within a few months after initiation of study. Duo either to death ar poor body conditions, 9 animais from treatment C, and 24 from treatment D were eliminated from the study. The animais in treatments A and 6 were heabthy and thus nono was removed. The average weight gain por animal was 143.8 kg for treatment A, 129.9kg for 6,61.7kg for C and 39.8 for treatment D. Biopsy of rib-bone and liver showed that animais from treatments C and D were deficient in P and Zn. The pasture was deficient or borderline in P, Zn, Cu and Co. Sou was poor ir, Ca, P. Mg, Zn, Cu and Co. Sou, pasture and animal tissues were ali deficient in P and Zn. Economic analysis under risk conditions pointed the superiority of treatmont A.