| In adequate ruminant livestock feed on smallholder farms is a problem concern in Kenya. In these farms, ruminant livestock rely heavily on low quality roughages, leading to poor animal performance. The situation is further compounded by lack of supplementation and the seasonal nature of feed supply. Due to high cost and scarcity of conventional protein and energy supplementation, use of high quality forages is widely accepted as the most feasible way to improve ruminant livestock production on these farms; hence the need for more research information on both conventional and non-conventional forages to enhance their production and utilization (Chapters 1 and 2). It was on this basis that the current work was conceptualized and it focused, on evaluating the forage potential of Sorghum almum (Columbus grass), Vicia sativa L (Common vetch), Vicia villosa Roth, Commelina diffusa and Commelina benghalensis (giant variety). All these forages are presently less used in Kenyan. The overall objective was to contribute towards the improvement of feed availability for ruminant livestock production on smallholder farms. Specific objectives were to determine: 1) effect of manure or fertilizer application on yield; 2) effect of advancing maturity on quality; 3) effect of these forages on animal performance and 4) effect herbage type and chemical composition on rumen microbial population (in vitro). Research hypotheses were formulated to guide the study (Chapter 1).To determine the effect of manure or fertilizer on yields and advancing maturity on quality, the forages were allotted to 3 treatments (T1– Not fertilized; T2– Manure and T3– DAP fertilizer) in a randomized complete block design and later harvested at 6, 8, 10, 12 and 14 weeks. Yield evaluation results are presented in Chapters 4 (Sorghum almum), Chapter 5 (Commelina benghalensis) and Chapter 6 (Vicia villosa Roth). Results showed that application of either manure (T2) or fertilizer (T3) significantly increased yield of Sorghum almum. T2 and T3 recorded 21.05% (17.1 ton DMY ha-1; P < 0.05) and 32.16% (19.9 ton DMY ha-1; P < 0.01, r2 = 0.7584) higher dry matter yield (DMY) than T1 (13.5), respectively at 14 weeks. It also increased canopy height (P < 0.0001; r2 = 0.9769). Results also showed that, age at harvest affected concentration of chemical constituents in Sorghum almum herbage. NDF in T1, T2 and T3 increased by 33.1, 36.04 and 27.95% respectively between 6 and 14 weeks, whereas that of CP declined by 66.67, 63.01 and 60.9% respectively over the same period. The mean ME values of 8.19, 8.49 and 9.13 MJ kg-1 DM recorded in the 3 treatments at 6 weeks also declined considerably with advancing maturity of the grass (Chapter 4). Results also showed that, between 6 and 14 weeks, P and K content decreased by 35.14 and 46.77% respectively. Those of Na, Ca, Mg, Cu, Mn and Zn also decreased by 46.49, 20.41, 21.74, 36.4, 27.4 and 57.1% respectively over the same period. Total amino acids (AA) decreased by 63.41% from 81.31 at 6 to 29.75 mg g-1 DM at 14 weeks.Similarly, manure and fertilizer application improved the yield of Commelina benghalensis with T2 and T3 recording 26.86 and 29.67% higher DMY respectively at 14 weeks than T1 (Chapter 5). As observe with Sorghum almum, results showed that, CF content in Commelina benghalensis herbage increased by 68.75, 59.19 and 58.84% between 6 and 14 weeks in T1, T2 and T3 respectively. Over the same period, CP content in Commelina benghalensis herbage in the 3 treatments decreased by 47.98, 40.61 and 48.89% respectively. From the results, it was noted that Mg level declined by 13.8% between 6 and 14 weeks, whereas that of K increased by 31.39% over the same period. Results also showed that Na, Ca and Zn content in Commelina benghalensis herbage, declined by 35.19, 49.78 and 66.68% respectively between 6 and 14 weeks. Concentration of total extractable phenolics increased by 64.95% while that of total amino acids decreased by 39.15% over the same period.For Vicia villosa Roth, results showed that soil fertilization increased DMY (r2 = 0.7341; P < 0.01) and OMY (P < 0.01; r2 = 0.7577) at 14 weeks but not on CPY (r2 = 0.3705; P > 0.05). From the results it was observed that, NDF in T1, T2 and T3 increased by 19.7, 14.1 and 19.2% between 6 and 14 weeks, respectively. Concentration of mineral elements, total extractable phenolics and amino acids in Vicia villosa also varied with advancing age.Experiments were also conducted to determine effect of advancing maturity of these forages on rumen degradability, rumen microbial characteristics and fermentation using in sacco (Nylon bag)(Chapter 7), Polymerase chain reaction– Single Strand Conformation Polymorphism (PCR– SSCP)(Chapter 7) and in vitro gas production (Chapter 8) techniques respectively. The mean DM degradability fractions ('b'and'a + b') for Sorghum almum, Commelina diffusa, C. benghalensis, Vicia sativa and V. villosa harvested at the same age were 47.46, 46.2, 64.11, 27.7, 63.13 and 69.14, 66.3, 84.19, 69.58, 86.24% respectively. Their corresponding effective degradability values (ED; at 5% h-1) were 43.97, 44.7, 58.33, 65.6 and 52.43% respectively. The mean CP degradability values for the'b'fraction and ED for the 5 forages were 54.56, 74.1, 73.29, 24.12, 64.27 and 42.37, 60.5, 45.73, 74.6, 53.53% respectively. Results further showed that potential DM and CP degradability of Sorghum almum declined by 8.74% (r2 = 0.5659; P < 0.01; N = 18; CV = 3.75) and 20.79% (r2 = 0.9015; P < 0.0001; N = 18; CV = 3.34) respectively between 6 and 14 weeks. Similarly, potential CP degradability of Commelina benghalensis and Vicia villosa declined by 12.06% (r2 = 0.7315; P < 0.01) and 9.11% (r2 = 0.6383; P < 0.01) respectively.Advancing forage maturity also negatively affected rumen microbial growth and colonization of the fibre. For Sorghum almum, Commelina benghalensis and Vicia villosa, in vitro microbial culture media based on herbage harvested at 6 weeks recorded 37.18 (P < 0.0001), 18.87 (P < 0.0001) and 10.72% (P < 0.000) higher bacterial mass, respectively than that based on herbage harvested at 14 weeks. The same was observed for protozoa population. PCR–SSCP results showed bands and kindred index values for microbes varied with diets, indicating effect of herbage maturity.A study was also carried out (Chapter 9) to investigate the effect of incremental level (0, 10, 20 and 30%) of Vicia villosa or Commelina benghalensis in Sorghum almum based diets on digestibility and N balance in Sheep. Results showed that, wethers offered diets comprising of 10, 20 or 30% Vicia villosa or Commelina benghalensis, recorded 31, 23.28, 19.9% or 27.9, 26.25, 36.61% high fresh matter intake (FMI) respectively, compared to those on Sorghum almum alone (P < 0.0001). Mean DMI and DM digestibility (%DMD) for wethers fed Sorghum almum were 306.2 g d-1 and 60.8%. For those on 10, 20 or 30% Vicia villosa or Commelina benghalensis, the DMI means were 391.9, 364.6, 356.3 and 348.1, 349, 370.7 g d-1, respectively. Wethers on Vicia villosa based diets recorded 65.7, 75.2 and 72.9% DMD (P < 0.0001) and 7.85, 8.25, 7.64 g d-1 N intake respectively. For the 3 supplementation levels, Commelina benghalensis recorded 5.36, 5.35, 5.74 g d-1 N intake respectively. Those on sorghum almum alone recorded a mean of 4.56 g d-1 N intake. Concentration of rumen fermentation products also varied with level of supplement in the diet. For Vicia villosa supplemented wethers, ammonia nitrogen (NH3-N) and volatile fatty acids (VFA) ranged between 66.27– 139.54 mg L-1 (P < 0.0001) and 88.72– 122.71 mmol L-1 (P < 0.0001) respectively. A range of 66.27– 104.73 mg L-1 NH3-N (P < 0.0001) and 88.72– 95.65 mmol L-1 VFA (P < 0.0001) was observed for those on Commelina benghalensis. Strong correlations were also observed between intake and increased level of supplement in the diet.Chapter 10 presents the outputs of the experiment conducted, in a randomized complete block design, to determine effect of using Commelina benghalensis (T2) Vicia villosa (T3) and Medicago sativa (T4) as protein supplements (at 20% of the total diet) on feed intake and weight gain of young wethers fed medium aged Sorghum almum (T1) as a basal diet. At the end of this study (84 days), the mean body weight of wethers in T1 was 17.86, 23.03 and 34.97% lower than those recorded in T2, T3 and T4 respectively. The mean average daily gain (ADG) in T1, T2, T3 and T4 were 128.97, 201.91, 213.89 and 263.09 g d-1 respectively (P < 0.0001; r2 = 0.8254). The mean dry matter intake (DMI) of wethers in T1, T2, T3 and T4 were 847.94, 896.22, 1056.53 and 1135.27 g d-1 respectively (P < 0.0001; r2 = 0.7684). Both ADG and DMI values indicate that supplementation improved performance of the wethers.From the results, it was clearly evident that manure and fertilizer application improved both yield and quality of the forages studied (Chapter 11). It was also clearly illustrated that advancing forage maturity strongly influenced chemical constituents and digestibility. Results also clearly showed that use of inclusion of Commelina benghalensis or Vicia villosa improved intake, digestibility and N utilization in sheep fed Sorghum almum. Based on these results, it was concluded that, while encouraging soil fertilization as means of improving yield of these forages, their optimal harvesting stages must identified to maximize on yield, concentration of essential nutrients and rumen degradability. Also based on the observed animal performance, it was further concluded that Commelina benghalensis and Vicia villosa could be used as supplements for low quality roughages to improve animal production on smallholder farms in Kenya. There is however, a need for more research to elucidate factors not adequately covered in the current work, particularly on Commelina spp and Vicia spp. ________________________________________________________________...
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