Valor nutritivo de los recursos alimenticios procesados procedentes de pastos naturales en South-West, Nigeria

The nutritive value of forage resources from natural grazing land as dry season feed supplements for grazing animals were evaluated through their chemical composition and in vitro gas production. The forage resources include conserved forages (hay and silage), browse plant (Leucaena leucocephala leaves) and the forages in the natural pasture during the dry season served as the control. Crude protein (CP) contents of the forage resources ranged from 59 to 171 g/kg dry matter (DM), with L. leucocephala leaves having the highest (p< 0.05) CP contents. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents of the forage resources ranged from 560 to 705 g/kg DM and 363 to 440 g/kg DM, respectively. The highest in vitro gas production of 38.7 ml/200mg DM was recorded for L. leucocephala leaves which was followed by silage and hay while forages in the natural pasture during the dry season recorded the least gas production. The volume of gas production significantly (p<0.05) ranged from 13.7 ml/200 mg DM in natural pasture to 38.7 ml/200 mg DM in L. leucocephala leaves. The fractional rate of gas production value of 0.10 h-1 was highest in L. leucocephala leaves and lowest in the silage with the value of 0.07 h-1. L. leucocephala leaves had the highest (p<0.05) values of ME, OMD and SCFA (16.8 MJ/ kg DM, 64.7 % and 0.8 µmol respectively while natural pasture recorded lowest values of 5.3 MJ/kg DM, 32.8%, 0.2 µmol for ME, OMD and SCFA respectively. The study showed that conserved forages (hay and silage) and browse plant (L. leucocephala leaves) were superior to forage in natural pasture during dry season in terms of CP and gas production, thus indicating higher nutritive potential. They may therefore be used as supplements for ruminants that are grazing on poor quality roughages during the dry season.