Characterization of selected Brachiaria accessions using morphology and chemical composition

Abstract

With the current trends with global climate change, pastures, especially in the tropics are producing poor quality forage characterized by low crude protein and high crude fiber contents that are unsuitable for sustainable livestock production. Improved Brachiaria cultivars being used in east Africa show susceptibility to different diseases which reduce their overall production. Recent studies have found a narrow genetic base of these improved cultivars with a high genetic similarity which reduces their adaptability to new and changing environments. This study was carried out to assess the yield and proximate composition of 20 indigenous Brachiaria accessions (B15 WKS, S6, B90 LIRA, S2, B29 FORT, B74 FORT, B85 LIRA, B78 HOIMA, B23 FORT, B97, B1 WKS, B52 ARUA, B63, B24 FORT, B6 WKS, S8, X120, B50 MBR, X135 and B6). Dry matter yield, percentage dry matter, crude protein content, ether extracts, crude fiber, nitrogen free extracts, Metabolizable energy, leaf: stem ratio, ash, plant height, leaf length, leaf width, inter-node length and stem diameter were determined for all the accessions. There were significant differences (P<0.05) in the dry matter yields, ash content, EE, CF, ME and leaf lengths of the different accessions but no significant differences (P>0.05) in CP, percentage dry matter, LSR, plant height, leaf width, internode length and stem diameters of the different accessions. Accession B78 HOIMA had the highest plant height (107.61 cm) and the highest dry matter yield (3726 KgDM/Ha), S6 had the highest leaf length (41.58 cm) and the highest crude fiber content (29.45%) while S8 had the highest leaf width (2.31 cm). B15 WKS had the highest inter-node length (10.7 cm) and stem diameter (1.61 cm). Accession B52 ARUA had the highest percent dry matter (30.01%) and NFE (49.89%), X120 had the highest ME (9.312 MJ/KgDM), the highest CP (16.52%) and the highest ether extract content (1.1635%), B23 FORT had the highest leaf: stem ratio (2.733) and accession B6 had the highest ash content (18.83%). All accessions were able to meet minimum CP requirement (7% and above) for rumen microbial function, while all accessions except S6 had ME exceeding 8.37 MJ/KgDM and are considered as good quality forages. From this study, the indigenous Brachiaria grass accessions have potential to supply livestock feed and can substitute conventional basal livestock feed livestock rations. It is recommended that the experiment should be conducted for a longer period of time and in different seasons to quantify the production of these accessions in both dry and wet periods. Further research is needed to assess the effect of feeding these Brachiaria accessions on animal performance.