Evaluation of global Cenchrus germplasm for key nutritional and silage quality traits

Abstract

Cenchrus is important genera of grasses inhabiting tropical pastures and the Indian grasslands system. Its forage value is well established to sustain nomadic livestock and wildlife. This study deals with the evaluation of the representative set of global Cenchrus germplasm collection with 79 accessions belonging to six species (C. ciliaris, C. setigerus, C. echinatus, C. myosuroides, C. pennisetiformis, and C. biflorus) at flowering stage. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose, and lignin values were in the range of 61.1-136, 640-749, 373-490, 277-375, and 35.6-75.50 g kg^-1DM, respectively, while sugar contents varied from 11.6 to 101 mg g^-1 DM. From the evaluated germplasm, 14 accessions of C. ciliaris having >70 mg g^-1 DM sugar contents were selected and further evaluated for protein, fiber, carbohydrate and protein fractions, palatability indices, in vitro CH₄ production, and ensiling traits. Protein contents were lower in EC397323 (61.8) and higher in IG96-96 (91.5), while the NDF, ADF, cellulose, and lignin contents varied between 678-783, 446-528, 331-405, and 39.6-62.0 g kg^-1DM, respectively. The carbohydrate and protein fractions of selected accessions differed (p < 0.05), and the sugar contents varied (p < 0.05) between 74.6 and 89.6 mg^-1g DM. Dry matter intake (DMI) and relative feed value (RFV) of accessions varied (p < 0.05) and were in the range of 1.53-1.77% and 58.2-73.8 g kg^-1 DM, respectively. The total digestible nutrients (TDNs), digestible energy (DE), and metabolizable energy (ME) of selected accessions varied between 362-487 g kg^-1 DM, 6.62-8.90, and 5.42-7.29 Mj kg^-1 DM, respectively. In vitro gas and CH₄ production (24 h) varied (p < 0.05) between 73.1 to 146 and 7.72 to 21.5 ml/g, respectively, while the degraded dry matter (g kg^-1 DM) and CH₄ (ml/g DDM) ranged between 399-579 and 17.4-47.2, respectively. The DM contents at ensiling, silage pH, and lactic acid contents of accessions differed (p < 0.05) and ranged between 185-345 g kg^-1 DM, 5.10-6.05, and 1.39-23.3 g kg^-1 DM, respectively. Wide genetic diversity existed in germplasm and selected C. ciliaris accessions for protein fiber, energy, sugar, and other nutritional traits. Silage prepared from EC397366, IG96-96, IG96-50, and EC397323 had pH and lactic acid contents acceptable for moderate to good quality silage of tropical range grasses.

Keywords: Cenchrus germplasm; energy value; ensiling; methane; sugar.