The potential of the weed, Commelina diffusa L., as a fodder crop for ruminants

The objective of this study was to evaluate the potential of Commelina diffusa L. as a ruminant feed. Commelina diffusa belongs to the Commelinaceae family, a family of plants that is generally poorly investigated with respect to ruminant nutrition. The species was evaluated in terms of its chemical composition, and through the in sacco technique, its rumen degradation characteristics. Rumen degradability was determined in three mature female goats, each fitted with a permanent rumen cannula. Commelina diffusa contained 177 g crude protein (CP)/kg dry matter (DM) and its CP had a rumen degradability of 74.1 ± 2.7%. Most of the DM and organic matter (OM) were lost during the first 36 h of incubation and the cell wall components after 48 h of incubation. Maximum (120 h) DM, OM, neutral and acid detergent fibre, hemicellulose and cellulose disappearances from the bags incubated in the rumen were 66.3, 57.8, 55.6, 55.2, 56.7 and 44.3%, respectively. Rumen degradation of DM and OM was correlated (r2 = 0.66), but significantly different. It is concluded that, from a nutritional point of view, C. diffusa compares well with many commonly used fodder crops and could be used as protein source for ruminants on smallholder farms. South African Journal of Animal Science Vol. 36(1) 2006: 28-3

Effect of maturity on the mineral content of Columbus grass (Sorghum almum)

This study was conducted in Naivasha, Kenya over a period of 15 weeks to determine the effect of maturity on mineral content in Columbus grass (Sorghum almum). Immediately after field preparation, representative soil samples were taken for mineral profiling. Thereafter, 60 plots 2 x 2 sq. m size were demarcated and allotted to 5 similar blocks of 12 plots each in a randomized complete block (RCB) design. Each plot received 25 g of seed evenly drilled to 5 rows (2 m length and 30 cm apart). All the plots were planted on the same day and kept weed free throughout the study. The grass was harvested at 6, 8, 10, 12 and 14 weeks after seed emergence in sequential manner beginning with block 1 to 5, each time leaving a stubble height of 5 cm. From each plot, representative herbage grabs were made, chopped into 2 cm pieces and mixed thoroughly. Two composite samples of about 500 g each were then taken for dry matter determination and mineral analysis using the standard procedures. Results showed that, the plant tissue levels of all mineral elements investigated were significantly affected by advancing grass maturity. Between 6 and 14 weeks, P and K decreased by 35.14 and 46.77% respectively. It was also noted that Na, Ca and Mg decreased by 46.49, 20.41 and 21.74% over the same period. Levels of trace elements also declined as the grass matured. Results showed that Cu, Mn and Zn levels decreased by 36.4, 27.4 and 57.1% respectively, between 6 and 14 weeks. Ca:P ratios however remained consistent over this period. It was generally observed that, although levels of macro-elements declined with advancing maturity of the grass, their overall concentrations remained within the recommended requirements for ruminant production. Trace element levels were generally below those desired for ruminant production. It was therefore concluded that macro-mineral elements might not be a problem in Sorghum almum based diets. Ruminants would however require additional source of trace elements to correct possible deficiencies of the same in their diets. Keywords: Macro–elements; Micro-elements; Ruminants; Diets; Supplementation Animal Production Research Advances Vol. 2 (3) 2006: pp. 134-13

Effect of supplementary soil nitrogen on yield of Vicia villosa Roth harvested at different maturity stages

A study was conducted in Naivasha, Kenya over a period of 15 weeks to determine the effect of supplementary soil nitrogen (SSN) on yield of Vetch (Vicia villosa Roth) under Kenyan climatic condition. After field preparation, representative soil samples were taken for mineral profiling. Sixty plots of 2 x 2 sq. m size were then demarcated and further divided into 5 similar units comprising 4 blocks of 3 plots each. The plots in each block were independently allotted to 3 treatments in a randomized complete block (RCB) design. Treatments were T1 – control (without SSN), T2 and T3 are manure and inorganic fertilizer (as sources of SSN), respectively. All the 4 blocks (weed free) in each of the five (randomly distributed) units were planted on the same day. Harvesting was done at 6, 8, 10, 12 and 14 weeks in a sequential manner starting with unit 1 to 5. All the blocks in each unit were harvested on the same day (at 5 cm height). All the freshly harvested materials, per plot, were weighed. Representative grabs of the material were made, chopped to pieces of 2 cm length, mixed and 2 composite samples (500 g each) were taken for dry matter (DM) determination and chemical analysis. DM, Ash and Crude protein (CP) were determined according to standard procedures. Fresh matter yield (FMY), DM yield (DMY), organic matter yield (OMY) and crude protein yield (CPY) per 4m2 and hectare were determined. Data was stored in MS-Excel and analyzed using SAS (2002) analytical models to determine the differences between treatments. Results showed that, at the age of 6 weeks, FMY and DMY (kg 4m-2) in T3 (1.83 and 0.24) were 23.6 and 34.1% higher (p>0.05) than T1 (1.48 and 0.179). Similarly, T2 (1.53 and 0.183) and T1 were also not different (p>0.05) at this age. At the 14th week however, the mean FMY in T1 (19.38) and T2 (22.51) were different (