Browsing by Author "Njoka, E. N."

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Characterization of clays from Tharaka-Nithi County in Kenya for industrial and agricultural applications
(2015) Njoka, E. N.; Ombaka, O.; Gichumbi, J. M.; Kibaara, D. I.; Nderi, O. M.
Clay samples from Tharaka-Nithi County in Kenya were characterized by hydrometer, X-ray fluorescence spectroscopy (XRF), atomic absorption spectroscopy (AAS), TGA, scanning electron microscopy (SEM) and powder diffraction (XRD) methods. The F-test and t-test were used to interpret the results. The major oxides present were Al2O3, SiO2 and the minor ones were CaO, TiO2, MnO, Fe2O3, K2O, MgO and Na2O. The values of SiO2 were greater than those of Al2O3, indicating that the samples were of clay minerals. The clay minerals with low cation exchange capacity (CEC) were present in the samples. The Atterberg limits showed that the inorganic clays of either low or intermediate plasticity having low contents of organic matter were present in the samples. The analysis further showed the availability of essential elements necessary for plant growth. The TGA analysis indicated that the decomposition of clay samples occurred in four steps. The scanning electron microscope photographs revealed that the samples contained a mixture of minerals of morphologies with crystallinity, high porosity and unstable under the electron beam. The major impurity in the clay is quartz, ranging from 22.6-31.9%. Albite is the most dominant component in the clay minerals contributing to 30.3 to 44.1%. The clay from the study area can be used as agro mineral additive to enhance soil fertility for crop production, a fluxing agent in ceramics and glass applications and also as functional fillers in the paint, plastic, rubber and adhesive industries after beneficiation.
Effects of Supplementing Chloris gayana Hay and Maerua angolensis with Graded Levels of Maize Germ Meal on Voluntary Feed Intake, Diet Digestion, Nitrogen Balance and Average Daily Gains of Growing Small East African Goats
(2010-07) Ondiek, James; Abdulrazak, Shaukat; Njoka, E. N.
Maerua angolensis and graded levels of maize germ meal were offered to Small East African goats to assess the effects on voluntary feed intake, diet digestion, nitrogen balance and growth. The M. angolensis was offered at a rate of 20 g kg-1 W0.75 to all animals and maize germ meal treatment diets was given at five graded levels (0, 15, 20, 25, and 30 gDM kg-1 W0.75) designated as MG0, MG15, MG20, MG25 and MG30, in a completely randomized block design with 4 animals per treatment with the basal diet of Rhodes grass (Chloris gayana) hay fed ad libitum. The CP levels were 320, 200 and 61.4 g kg-1 DM for M. angolensis, maize germ and C gayana hay, and NDF contents were 449, 393 and 528 g kg-1 DM, respectively. The DMI was 461-599 g DM d-1 which increased with energy supplementation (P<0.05) although the supplemented groups did not differ and the goats consumed the feed at 3.72-4.53% of their live weight. The ADG was 4.92, 23.7, 26.4, 34.4 and 35.7 g d-1, respectively, with MG25 and MG30 being similar (P>0.05). The rumen NH3-N was in the normal range of 1.85-2.63 mg100 ml-1 while the nitrogen balance was in the range of 2.90-7.68 mg N/100 ml for MG0 and MG30, respectively. The DM, OM, CP, ADF and NDF digestibility was improved with supplementation, but supplemented animals had similar values (P>0.05). It is concluded that the maize germ meal supplemented at 25 g DM kg-1 W0.75 had high rumen NH3-N, N-retention and ADG 8.16 mg-1 100 ml, 6.25 g Nd-1 of 34.4 g d-1, respectively, and this can be used together with M. angolensis at 20 g DM-1 W0.75 to make use of the tree forage and low quality basal diet for growing Small East African Goats.
Nutritive value and Palatability rating of fifteen Selected Indigenous Kenyan Browse Species fed to Small East African Goats.
(Livestock Research for Rural Development 29 (6) 2017, 2017-06) Ondiek, J. O.; Abdulrazak, S. A.; Njoka, E. N.
A palatability study was conducted using fifteen indigenous multipurpose tree leaf forages offered to twenty intact male Small East African Goats, 7 to 8 months and 18kg ± 2.1kg. The CP (gkg-1DM) of the best five species were: M. angolensis (321), A. senegal, (249),Z. mucronata, (200), G. bicolor, (196) and A. brevispica, (187). The NDF and ADF contents ranged from 218-601 for A. hockii and A. amara, and 160-462 for A. hockii and A. abyssinica, respectively. The palatability ranking of the forages was in the order: A. tortilis> M. angolensis> B. aegyptiaca> Z. mucronata> A. coriaria> A. Senegal> A. abyssinica> A. mellifera> A. brevispica> A. elatior> A. amara> G. bicolor> A. nilotica> B. micrantha> A. hockii. M. angolensis and Z. mucronata had OMD of 68.0 and 73.8%, respectively. M. angolensis, Z. mucronata ranked highly on the parameters studied. It is concluded that Maerua angolensis and Zizyphus mucronata being high in nutritive value and palatability, are potential protein supplements to low quality basal diets.
Supplementing Rhodes grass Chloris gayana hay with Maerua angolensis improves weight gain of growing small East African goats
(2018) Ondiek, J. O.; Abdulrazak, S. A.; Njoka, E. N.
To study the performance of Small East African goats fed Rhodes grass(Chloris gayana) hay supplemented with 5 levels of Maerua angolensis (0, 15, 20, 25, 30g DM W0.75) 20 goats were divided into five groups and randomly assigned five treatments in a randomized complete block design based on initial body weight (10.3±1.3kg). The treatment diets were offered twice daily at 08.00 and 14.00 hours with C. gayana and clean water were available ad libitum. Feed intake increased with increasing level ofM. angolensis, whereas, average daily gain, digestibility of DM, CP, NDF and rumen NH3N were the highest on 20g supplementation level. It is concluded that M. angolensis is a potential protein source and can be supplemented at 124 gd-1 (or 20% of metabolic weight, i.e. 20gDM/kgW0.75) for growing Small East African goats.