Suplementação mineral e mobilização de cálcio nos ossos de eqüinos em pastagem de Brachiaria humidicola

Abstract

Pesq. agropec. bras., Brasília, v.34, n.5, p.873-878, maio 1999 SUPLEMENTAÇÃO MINERAL E MOBILIZAÇÃO DE CÁLCIO 873 INTRODUÇÃONa Região Centro-Oeste do Brasil o cavalo é considerado como um instrumento de trabalho e transporte nas fazendas de rebanho bovino, não importando cor, sexo, tamanho ou raça. Por serem herbí-voros e para evitar custos adicionais na proprieda- Termos para indexação: biópsia óssea, oxalato. SUPLEMENTAÇÃO MINERAL E MOBILIZAÇÃO DE CÁLCIO NOS OSSOS EFFECT OF MINERAL SUPPLEMENT ON CALCIUM MOBILIZATION FROM BONE OF EQUINE GRAZING BRACHIARIA HUMIDICOLAABSTRACT -During 150 days 12 female Quarter Horse yearlings at one year of age were kept solely on Brachiaria humidicola pasture, on a complete randomized design, with three treatments and four replications: level 0 (NRC1989); level 50 (50% above NRC); level 100 (100% above NRC). It was used 270 g of sugar as an intake promoter. Biopsis were perfomed on the wing of ileum of each animal, one at the onset and the other at the end of trial, in order to evaluate Ca mobilization and Ca:P of the bone. Forage samples were collected monthly to evaluate oxalate levels and chemical composition. There was a time effect on Ca mobilization and Ca:P (P< 0.05), regardless the treatments. The average of the three treatments, at the onset and at the end of the trial, for Ca and P levels and Ca:P was, respectively: 10.05, 5.22, 1.93:1 and 6.24, 4.06, 1.54:1. The levels of oxalate in the grass varied from 1.18 to 2.00%. Suplementing Ca to young horses at a level 200% greater than the National Research Council recomendation did not prevent Ca mobilization from the bone when the animals were grazing Brachiaria humidicola for an extended period of time.