Mineral composition, palatability and digestibility of free rangeland grasses of northern grasslands of Pakistan.

摘要

A study was conducted in the valley of Chagharzai in Bunair district lying in the north Trans-Himalayan moist zone occupying Malakand Division, North Western Frontier Province (NWFP), Pakistan to determine mineral composition, palatability and digestibility of locally available free rangeland grasses. The study area lies between 34.42 to 34.66 degree latitude and 72.62 to 72.78 degree longitude, having a humid subtropical to temperate environment. The annual precipitation varies from 600 to 1000 mm, mainly during summer and spring. Ten free rangeland grasses were identified for macro-minerals (Ca, P, K and Mg) and micro-minerals (Cu, Zn, Mn and Co). The mean percentage values for Ca, P, K and Mg at early bloom stage were 0.26+or-0.022, 0.025+or-0.004, 0.69+or-0.113 and 0.044+or-0.006, respectively. The mean ppm values for Cu, Zn, Mn and Co at early bloom stage were 22.75+or-2.671, 14.70+or-2.065, 10.12+or-1.770 and 0.023+or-0.003, respectively. The mean percentage values for Ca, P, K and Mg at maturity were 0.30+or-0.049, 0.031+or-0.006, 0.68+or-0.108 and 0.028+or-0.004, respectively. The mean ppm values for Cu, Zn, Mn and Co at maturity were 29.8+or-2.962, 8.96+or-2.0701, 6.14+or-1.034 and 0.029+or-0.005, respectively. In free grazing rangeland grasses the highest (pHeteropogon contortus (53.80+or-15.82 g/4 minute) and lowest for Cymbopogon schoenanthus (35.8+or-12.16 g/4 minute). However, the highest (pDichanthium annulatum (81.15+or-0.61.) and lowest for Cymbopogon schoenanthus (19.33+or-1.84). The mean In vitro dry matter digestibility (IVDMD) and metabolizable energy (ME) of free rangeland grasses at early bloom stage were 55.3+or-1.86 and 7.57+or-0.25 MJ/kg DM, respectively, whereas, the mean IVDMD and ME at mature stage were 44.0+or-2.11 and 5.86+or-0.29 MJ/kg DM, respectively. The macro and micro mineral composition, IVDMD, RP and PIR values indicate that free grazing rangeland grasses be fed to livestock with some supplementation for different levels of production and types of livestock.