Evaluation of Macro and Micro Mineral Concentrations of Browse Forages in Relationto Ruminants Requirement: a Case Study of Gwoza, Borno State, Nigeria

Abstract

Information is lacking on mineral nutritive potential of native pastures in pastoral rangelands in the tropics including Nigeria. An experiment, using wet nitric acid (HNO₃) digestion in a micro wave digester followed by an induced coupled plasma spectroscopy (ICPS), was carried out to quantify levels of macro and micro minerals of in situ conserved herbage forages of Gwoza local Government area of Borno State, Nigeria. The browse forages had variable levels of Ca, P, Mg, Na and K (ranges of  5.10-19.30, 110.70-665.80, 1.80-10.40, 0.50-1.30 and 11.50-120.00 g  kg^-1 of dry matter (DM), respectively, and were higher than the minimum recommended levels in the diets of ruminants. Content of micro minerals varied among the browse forages. The forages had higher levels of Fe (1.618-10.96 mg kg^-1 DM) moderate contents of Zn (1.064-5.725 mg g^-1 DM) compared to recommended dietary requirements of ruminants. The feeds had lower levels of Mn (0.234-0.887 mg g^-1 DM), and lower levels of Co (0.004-0.011 mg kg^-1 DM). The browse feeds had moderate levels of Se (0.085-0.168 mg g^-1 DM). The levels of Ni ranges between 0.006-0.085 mg g^-1 DM) considerably in excess of requirements. In order to optimise livestock productivity in ruminants fed on the deferred forages, specially during dry seasons, there is a need to supplement with micro mineral sources.

Keywords: Browse, Fodder, herbage, minerals, natural pasture, Tanzania