LAUSR

BACKGROUND Information on the nutritive value, dry matter (DM) digestibility and methane (CH4 )-emission potential of the grass species are required for their optimal utilization in ruminant rations. The present study was designed: (i) to quantify the nutrient profile, mineral composition and in vitro dry matter digestibility (IVDMD) of winter grass species commonly available in Northern Pakistan; and (ii) measure the in vitro gas production (IVGP) and CH4 emission of the grass species during 72 h in vitro ruminal fermentation. Seven grass species, namely, Cenchrus ciliaris, Setaria anceps, Panicum antidotale, Panicum maximum, Pennisetum purpureum, Pennisetum orientale and Atriplex lentiformis were assessed. RESULTS Large variability (P < 0.001) was observed among grass species for the contents of all measured nutrients, IVDMD, IVGP and CH4 -production. Notably, the content (g kg-1 DM) of crude protein varied from 59.8 to 143.3, neutral detergent fibre from 560.3 to 717.9, IVDMD from 375.1 to 576.2, and 72 h cumulative IVGP from 97.6 to 227.4 mL g-1 organic matter (OM) and CH4 from 48 to 67 mL g-1 OM. Among the grasses, P. antidotale had greater content (g kg-1 DM) of CP (143.3), IVDMD (576.2), 72 h cumulative IVGP (227.4 mL g-1 OM) and produced smallest amount of total CH4 (48 mL g-1 OM) during 72 h fermentation. In contrast, A. lentiformis had smallest content (g kg-1 DM) of CP (59.8), IVDMD (375.1), 72 h cumulative IVGP (97.6 mL g-1 OM) and produced greater amount of total CH4 (67 mL g-1 OM) during 72 h fermentation. CONCLUSION The findings of current study highlight that, it is possible to select and further develop grass species with high nutritional value and lower CH4 -production, which can improve livestock productivity, farms profitability, and long-term environment sustainability. This article is protected by copyright. All rights reserved.