Changing Patterns of Minerals in Tropical Forages at Differet Maturities

Abstract

An experiment was conducted to investigate the mineral status as wellas dry matter, protein and lignocellulose contents of guinea, para and ruzi grasses grown in Pakchong soil series at Muak Lek, Saraburi at 3, 5, 7 and 9 weeks of maturity. Dry matter and protein contents are influenced (P<.01) by grass species, maturity and interaction between the two parameters. It was observed that protein of the grasses decreased (P<.01) while dry matter and lignocellulose increased with mturity. Significant effects of grass species, maturity and interaction between the two parameters on the concentration of different minerals were also found. With the exception of K and Fe, the concentration of Ca, P, Mg, Na, Cu, Zn and Mn differed (P<.05) among grass species. With increasing maturity, the concentration of Ca, P, Mg, Na, K and Mn in the grasses decreased while that of Fe and Zn increased (P<.05). The changing patterns of element concentrations with maturity imply that Ca, P, Mg, Na, K and Mn found in the three tropical grasses are in mobile forms while those of Fe and Zn are non-mobile. In addition, condidering the daily requirement of the various minerals in dairy cows, it is evident that Ca and Cu in all three grass species, Zn in guinea and para grasses and Na and Mn in ruzi grass grown in this area are deficient.