Browsing by Author "Siamba, Donald N."

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Acute oral toxicity evaluation of some polyherbal formulations in albino wistar rats.
(Orgz, 2008) Vijayabalaji, V.; Joshua, Allan J.; Kumar, Pavan G.; Murali, B.; Suryanarayana, ML.; Siamba, Donald N.
The objective of the current study was to assess the acute oral toxicity of some herbal veterinary preparations in female albino Wistar rats as per the OECD guidelines for testing of chemicals, Acute oral toxicity-Fixed dose procedure (Test guideline 420). The investigational substances, NaturalivTM liquid and Zist® liquid are used in poultry for hepatoprotective and antioxidant properties, respectively. NaturalivTM liquid was tested at 5000 mg kg-1 b.wt., whereas Zist® liquid was evaluated in sequential manner to one animal each at 2000 and 5000 mg kg-1 b.wt. in the sighting study, followed by four animals at 5000 mg kg-1 b.wt. in the main study. The treated animals were observed for mortality (twice daily), adverse clinical signs (once daily), changes in weekly body weight gain and gross necropsy findings. All the treated animals survived throughout the study period.
Agriculture chemicals’ related hazards control
(KARI publication unit, 2014) Ondieki, JO.; Lanyasunya, TP.; Lokwaleput, IK.; Mutunga, TK.; Siamba, Donald N.; Bwire, JM.
IN recent years, food safety standards have become a more prominent issue for global trade in agricultural and food products (Jaffee and Henson, 2004a; and Josling et al., 2004). Of particular concern is the potential impact of food safety standards, whether promulgated by governments or private sector buyers, on the ability of developing countries to gain and maintain access to markets for highvalue agricultural and food products, especially in industrialised countries. In part this reflects the growing preponderance of these standards, but also more widespread recognition of the degree and manner in which trade flows can be affected. Concerns are greatest in the case of low-income countries, given their typically weaker food safety and quality management capacities that can thwart efforts towards export-led agricultural diversification and rural development. This paper explores the impact that food safety standards are having on the performance of developing countries with respect to agricultural and food product exports, drawing on a programme of research at the World Bank (see World Bank, 2005). While recognising that food safety and quality standards can act to impede exports, an attempt is made to ‘rebalance’ the policy debate in this area. The paper outlines how the proliferation and increased stringency of food safety standards is creating a new landscape that, in certain circumstances, can form a basis for the competitive repositioning and enhanced export performance of developing countries. In particular, the foundations of this competitive repositioning is explored and related, in turn, to the manner in which developing country governments and/or private sector suppliers respond to evolving standards.
Analysis of fecal coliform levels at watering points along the upper reaches of river Isiukhu in Kakamega county, Kenya
(2018-04-24) Kindiki, Sarah.; Kollenberg, Mario.; Siamba, Donald N.; Sifuna, Anthony.; Wekesa, Clabe.
Diarrheal diseases often attributable to poor sanitary conditions and fecal contamination of drinking water remain a leading cause of mortality for children younger than five years. Water contaminated with human faeces, for example from municipal sewage, septic tanks and latrines, is of particular concern. Animal faeces also contain microorganisms that can cause diarrhea. Kakamega County in Kenya has a diarrhea prevalence rate of 20.2%, which is the highest in the country; a good proportion of these cases are believed to be water borne. This study was designed to determine fecal coliform levels in water samples collected from watering points along the upper reaches of River Isiukhu in Kakamega County, Kenya. Fifty-four samples were collected between August and October 2015 from nine sampling points, comprising springs and watering points along the river. Water samples were filtered on nitrocellulose filters by vacuum filtration; fecal coliform counts were conducted using membrane filters cultured on mFC agar to establish contamination levels. The results indicated that counts ranged from 200 cfu/100 ml – 1450 cfu/100 ml in river sampling points and ranged from 0 cfu/100 ml – 44 cfu/100 ml in springs sampling points. The fecal coliform counts for River Isiukhu and most springs surrounding it exceeded the WHO recommended drinking water coliform (or E. coli) count value of 0 cfu/100 ml indicating that water from the upper reaches of River Isiukhu and springs is not fit for drinking before treatment, especially during the wet seasons, based on WHO drinking water standards.
Bacterial causes of bovine mastitis and their antibiotic sensitivity patterns in Western and Central Kenya
(The Kenya veterinary association, 2013) Ndirangu, PN.; Wesonga, HO.; Siamba, Donald N.; Mugambi, JM.
A cross sectional study was carried out from November 2008 to April 2009 to estimate prevalence of mastitis and to see associated bacterial pathogens in lactating dairy cows in Holeta town. A total of 107 cross bred milking cows were tested using California Mastitis Test (CMT). Prevalence of mastitis at cow level was 71.0% (76/107), out of which 22.4% (24/107) and 48.6% (52/107) were clinical and subclinical, respectively. The quarter level prevalence was 44.9% (192/428);from this the clinical and subclinical forms were 10.0% (43/428) and 34.8% (149/428), respectively. Out of the 43 quarters with clinical cases, 31 had blind teats while 12 of them revealed active cases of mastitis. Samples from all 12 active clinical cases and 90.0% (134/149) of the CMT positive subclinical quarters were found to be culture positive. From 146 culture positive samples, a total of 153 bacteria were isolated, the most prevalent being S. aureus (47.1%) followed by Coagulase negative Staphylococcus (CNS) (30.1%). Other bacterial isolates included Streptococcus (7.2%), E.coli (4.6%), Micrococcus species (3.3%), Klebsella pneumonae (3.3%), Enterobater aerogen (1.3%), Corynebacterium species (2.0%) and Bacillus (1.3%). Risk factors analysis revealed that prevalence significantly differed with the age (P < 0.05), parity (P < 0.05) and udder hygiene condition (P < 0.03).Thus, prevalence was relatively higher in adult cows (OR = 2.0; 95% CI = 1.15, 3.64), cows with moderate calves (OR = 2.4; 95% CI = 1.6, 3.6), cows with injured teat (OR = 7.7, 95%CI = 0.9, 64.1) and cows with unwashed udder (OR = 2.3, 95% CI = 0.8, 6.4) than those corresponding animals. In conclusion, this study revealed the importance of mastitis and associated bacterial pathogen in the study area.
Can fodder diets increase goat production by a quantum leap?
(Egerton University, Njoro, Kenya, 1992) Semenye, PP.; Siamba, Donald N.; Shisya, M.; Getz, W.
Growing goats, 45 Alpine and 45 Nubian, were used in a 3 × 3 factorial arrangement to quantify the influence of dietary energy and protein levels on daily DM intake and nutrient utilization for growth. Goats had ad libitum access to complete mixed diets containing either 2.46, 2.77 or 3.05 Mcal/kg ME plus 11.2, 12.7 or 15.1% CP for 16 wk. Dry matter intake decreased curvilinearly as dietary ME density increased (P < .001). Dry matter intake increased linearly (P < .05) as dietary CP level increased during all growth intervals except wk 25 to 28 of age. Average daily gain was 115, 113 and 99 g/d for goats fed diets containing 2.46, 2.77 and 3.05 Mcal/kg ME, respectively. Average daily gain was 104, 106 and 117 g/d for goats fed diets with 11.2, 12.7 and 15.1% CP, respectively. Dry matter intake was higher (P < .01) for Alpine than for Nubian goats, whereas ADG was similar between breeds. Intake of ME was 248, 260 and 198 kcal/(kg.75.d) for goats fed the low- medium- and high-energy diets, respectively. Intake of CP was 9.1, 10.7 and 13.2 g/(kg.75.d) for goats fed low-, medium- and high-protein diets, respectively. Average requirements for growth derived from regression analysis of all data points were 4.6 kcal ME and .26 g CP/g ADG. The prediction equation for intake of growing goats of 4 to 8 mo of age was: DMI, g/d = 1,749 - 496 DE, kcal/g + 18 live weight, kg + 3 ADG, g/d; r2 = .73 (Sy.x = 127, P < .0001, n = 90). The requirement of ME for growth was 33% lower than the value recommended in 1981 by the National Research Council.
Changes in lipids utilisation during moisture and temperature stress of infective (L3) and its implication on the epidemiology of Haemonchus contortus in arid and semi arid lands
(Maxwell science publishing, 2011-03-05) Siamba, Donald N.; Gatongi, PM.; Mulambalah, CS.; Ngeiywa, MM.; Wamae, LW.; Wambugu, A.
A study was undertaken to establish the pattern and level of lipid utilization in third stage infective larvae (L_3) of Haemonchus contortus under temperature and moisture stress conditions. The stress factors were representative of an arid and semi arid site in Kenya. The L_3 were subjected to gradual increase and reduction in temperature and moisture, respectively, using a programmable cold/heat testing chamber. Optical density per area (Corrected average pixels) derived from image analysis of individual stained larvae using an image analysis software (UN SCAN IT gel^(r)), were used to estimate the lipid content of larvae subjected to different stress treatments. It was observed that lipid content of the L_3 declined and was negatively correlated with duration of exposure with significantly (p = 0.012) lower rates in moisture compared to temperature stressed L3. It was also observed that the decline occurred in phases signifying possible adaptive physiological process aimed at preserving lipid reserves and viability. During revival, there was a drastic decline in lipid reserves probably as a result of increased lipid utilisation by the reviving larvae. The epidemiological significance of these findings in field larvae is discussed
Characteristics of rural poultry production in different agro-ecological zones in Kenya
(1998-11-09) Ndegwa, JM.; Kimani, CW.; Siamba, Donald N.; Mukisira, EA.; Jong, R de.
A cross-sectional was conducted to establish the characteristics of rural poultry production in Nyandarua, Nakuru and Laikipia districts of Kenya. Sites of diverse agroecological zones (AEZ) in the 3 district were selected, thus Ol Kalou in Nyandarua, Njoro in Nakuru and Ng'arua in Laikipia. Each site was divided into 4 clusters according to AEZ and land size. Systematic sampling techniques were applied to select farmers. A checklist was then used to collect the baseline information for every household. The study revealed that the average flock size was 17.3 chicken with Ng'arua region demonstrating the largest flock size of 21 chickens. The purpose of rearing indigenous chicken were stated as home consumption and sale of eggs and meat, hatching eggs, and as gifts.Farmers in Ng'arua region reported the highest sale of eggs and chicken meat. the average number of broodings per year, number of eggs laid before a chicken becomes broody, eggs set for hatching and hatchability was 2.5, 16.5, 11.1 and 84.2%, respectively. The average chick mortality reported by farmers in te first eight weeks was 47.9%. Disease especially Newcastle, were cited as the main cause of mortality. Farmers did not commonly practice selection for genetic improvement, but occasionally they purchased a cock or hen to control inbreeding. In all the 3 regions, 78.4% of the respondents indicated that women took greater responsibility and decision making in the production of indigenous chicken; 54.8% of farmers used different herbs to treat and control diseases. Conventional vaccination,disinfection and deworming rarely practiced. On most farms, chickens were left to scavenge around the homestead, often they were supplemented with kitchen leftovers and a handful of grains. The survey results demonstrated that there was potential for improving rural poultry production through interventions using appropriate technologies that are currently on-shelf.
Characterization of the livestock production system and potential to enhance productivity through improved feeding in Kisumu west, Kisumu, Kenya
(ILRI, 2014) Muyekho, N.; Francis.; Siamba, Donald N.; Humphrey, Humphrey.; Nyagol, Dickens.; Karugara, Dosa.
The Feed Assessment Tool (FEAST) was used to characterize the feed‐related aspects of the livestock production system in Matayos, sub County, Busia County of Kenya. The assessment was carried out through focused group discussions (FGDs) and completion of short questionnaires at 3 sites representing peri-urban and near tarmac road and typical rural setup. At each site nine key farmers were interviewed, 3 each owning small, medium and large scale farms on the 22nd of November and 3rd December 2013. The farming system is a mixed crop livestock production system. Cattle (predominantly local) are the most important livestock species In Matayos Sub-county. Improved dairy production is constrained by inadequate feeds and high cost of disease control in all the wards. Lack of improved breeds in Nasewa and Lwang’a and milk marketing are also constraints that require attention to activate commercial dairy productivity in the sub-county. To mitigate these constraints farmers suggested an integrated approach to improve livestock production through (i) expanding area under fodder crops with those tolerant to Napier grass stunt disease and those tolerant to drought, (ii) improving access to animal health and AI facilities to ensure farmers can rapidly upgrade the genetic merit of their cattle holdings especially in Nasewa and Lwang’a, (iii) access to credit facilities to enable farmers invest in livestock production enterprises and also milk marketing strategies.
Control ticks
(2003) Siamba, Donald N.
Ticks impact human and animal health worldwide and new control methods are needed to circumvent drawbacks of tick control by acaricide application including selection of drug resistant ticks and environmental pollution. Using RNA interference we silenced the expression of a single gene, subolesin, and produced ticks with diminished reproductive performance and prevented successful mating and production of viable offspring. We propose a sterile acarine technique (SAT) for reduction of tick populations by release of subolesin-silenced ticks. Conservation of subolesin among tick species suggests that SAT may be useful for control of many medically and economically important tick species.
Dairy cattle farming in Kenya. A practical training manual for extension workers
(2016) Siamba, Donald N.; Lanyasunya, TP.; Kariuki, JN.
This easy-to-use guide to effective targeting of selected dairy interventions in Kenya is intended for use by anyone involved in dairy farming in the country, such as development planners, researchers, service providers, suppliers of dairy inputs and extension workers. The guide answers the question often faced by these workers: where is their proposed intervention most likely to be adopted? Using a combination of Geographical Information Systems (GIS) mapping methods and economic regression techniques, this guide shows where and under what circumstances dairy technologies are most likely to succeed. The guide is divided into three sections. The first section deals with concepts, rationale and methodologies for targeting dairy interventions. It also explains, with examples, how to use the guide. The second section presents the targeting maps for various dairy interventions. A total of eleven dairy interventions are considered in this guide. For each, a map shows relative probability of adoption together with a description of the innovation and background information. Also presented are the socio-economic, biophysical and agro-climatic characteristics that predispose uptake of each intervention. The third section presents some policy-relevant research results in three topical areas: Cost of milk production; Evaluation and assessment of alternative milk preservation techniques; and Employment generation in the dairy marketing chain.
Dynamic risk model for rift valley fever outbreaks in Kenya based on climate and disease outbreak data
(Geospatial health, 2016-05-31) Gikungu, David.; Wakhungu, Jacob.; Siamba, Donald N.; Neyole, Edward.; Muita, Richard.; Bett, Bernard.
Rift Valley fever (RVF) is a mosquito-borne viral zoonotic disease that occurs throughout sub-Saharan Africa, Egypt and the Arabian Peninsula, with heavy impact in affected countries. Outbreaks are episodic and related to climate variability, especially rainfall and flooding. Despite great strides towards better prediction of RVF epidemics, there is still no observed climate data-based warning system with sufficient lead time for appropriate response and mitigation. We present a dynamic risk model based on historical RVF outbreaks and observed meteorological data. The model uses 30-year data on rainfall, temperature, relative humidity, normalised difference vegetation index and sea surface temperature data as predictors. Our research on RVF focused on Garissa, Murang’a and Kwale counties in Kenya using a research design based on a correlational, experimental, and evaluational approach. The weather data were obtained from the Kenya Meteorological Department while the RVF data were acquired from International Livestock Research Institute, and the Department of Veterinary Services. Performance of the model was evaluated by using the first 70% of the data for calibration and the remaining 30% for validation. The assessed components of the model accurately predicted already observed RVF events. The Brier score for each of the models (ranging from 0.007 to 0.022) indicated high skill. The coefficient of determination (R2) was higher in Garissa (0.66) than in Murang’a (0.21) and Kwale (0.16). The discrepancy was attributed to data distribution differences and varying ecosystems. The model outputs should complement existing early warning systems to detect risk factors that predispose for RVF outbreaks.
The effects of feeding Calliandra Calothyrus at different patterns as a supplement to Rhodes grass hay on intake, nitrogen utilization and milk yield of dual purpose goats.
(KARI, 2004) Muia, JMK.; Romney, DL.; Siamba, Donald N.; Nguru, JN.; Kariuki, JN.
Calliandra calothyrsus is a tree legume native to Mexico and Central America. The species has attracted considerable attention for its capacity to produce both fuelwood and foliage for either green manure or fodder. Its high content of proanthocyanidins (condensed tannins) and associated low digestibility has, however, limited its use as a feed for ruminants, and there is also a widespread perception that wilting the leaves further reduces their nutritive value. Nevertheless, there has been increasing uptake of calliandra as fodder in certain regions, notably the Central Highlands of Kenya. The present study, conducted in Embu, Kenya, investigated effects of provenance, wilting, cutting frequency and seasonal variation both in the laboratory (in vitro digestibility, crude protein, neutral detergent fibre, extractable and bound proanthocyanidins) and in on-station animal production trials with growing lambs and lactating goats. The local Kenyan landrace of calliandra (Embu) and a closely-related Guatemalan provenance (Patulul) were found to be significantly different, and superior, to a provenance from Nicaragua (San Ramón) in most of the laboratory traits measured, as well as in animal production and feed efficiency. Cutting frequency had no important effect on quality; and although all quality traits displayed seasonal variation there was little discernible pattern to this variation. Wilting had a much less negative effect than expected, and for lambs fed calliandra as a supplement to a low quality basal feed (maize stover), wilting was actually found to give higher live-weight gain and feed efficiency. Conversely, with a high quality basal diet (Napier grass) wilting enhanced intake but not live-weight gain, so feed efficiency was greater for fresh material. The difference between fresh and wilted leaves was not great enough to justify the current widespread recommendation that calliandra should always be fed fresh.
Effects of supplementation on cows with impaired fertility in Koibatek and Nakuru districts Kenya
(1999) Lokwaleput, I; Siamba, Donald N.
In a survey conducted in 1996, 82 and 60 cows with impaired fertility were found on 63 and 53 farms in Koibatek District and Bahati division, Nakuru district, respectively. These cows were appraised visually for body condition, and rectal palpation was done to determine the condition of their reproductive organs. The survey revealed that about 50% of the cows were in poor condition; about 60% were in anoestrus, thus indicating the effect of nutrition. Work carried out earlier in Kiambu, Nyandarua and Nakuru districts of Kenya to ascertain factors causing impaired fertility in cows on-farm, showed that management factors and most importantly, nutrition has the greatest effect. These study has therefore confirmed this phenomenon. An on-farm experiment was therefore conducted from mid -November, 1996 to early March, 1997 to determine effects of feeding supplements on the reproduction performance of cows fertility with calving intervals 1.5 years. Thirty six cows on 32 farms in Koibatek were assigned to three treatments: 14 to Dairy meal (DM), 12 to minerals (MIN) and 10 to Dairy meal and minerals (DM+MIN). In Bahati 40 cows, each on a farm were assigned to four treatments: 10 to DM, 10 to MIN , 10 to DM+MIN and 10 to Free grazing (FG). Apart from normal grazing or Stall-feeding, experimental animals were fed daily for 105 days with additional concentrates (DM=2 kg) Dairy meal and/or minerals (MIN: 50 g Maclick super). Freely grazed animals without supplementation acted as controls. Cows were monitored for reproductive events, liveweight changes and milk production. At the start of the experiment, the liveweights of the animals were 356 and 343 kg in Koibatek and Bahati, respectively. During supplemetation, the average liveweights of the cows increased by 18 and 25 kg, while milk production increased by 10 and 5% in Koibatek and Bahati, respectively. These increases were for cows on DM+MIN and were realized during the second month of supplementation. cows on treatments DM, MIN and FG demonstrated lower gains than those on DM+MIN; the effects of Drought further diminished there weight gains. In Koibatek, the percentages of cows that calved out of the total number were 50% for DM, 58% for MIN, and 80% for DM+Min. In Bahati, they were 60% for DM, 50% for MIN, and 70% for DM+MIN and 30% for FG. The study demonstrated that supplementation reduced the interval between the start of the supplementation and conception by an average of 130.0 days
Evaluating characteristics of indigenous chicken system with flock size trends in a participatory research on improved management practices in Kenya
(2015) Ndegwa, JM.; Meada, R.; Norrish, P.; Shepherd, DD.; Kimani, CW.; Wachira, AM.; Siamba, Donald N.; Ndegwa, Joseph M.
Analysis and evaluation of agricultural systems use these criteria: energy, economic, agronomy, environmental conservation and time. Because of time importance indicator for reducing timeliness cost, project scheduling techniques are used. Graphical Evaluation and Review Technique (GERT) is widely used as a tool for managing projects. In this research GERT Networks were used and operations scheduling of sugarcane production (land preparation, planting and preserve operations) in Khuzestan province of Iran as a case study was analysed, by using WinQsb software. Critical activities, events and path were determined. The earliest project completion time is 214.03 days. The results show a high potential for operations scheduling of sugarcane production.
Evaluating interventions uptake in indigenous chicken production in a participatory research with smallholder farmers in Kenya
(2015) Ndegwa, Joseph M.; Mead, Roger.; Norrish, Patricia.; Shepherd, Derek.; Kimani, Catherine.; Wachira, Anne.; Siamba, Donald N.
Indigenous chicken production system has long been characterised by low productivity due to among other factors, poor management, inadequate and poor feeding regime, poor (or lack) of disease control measures, poor hygiene, inappropriate housing, negative attitudes, lack of technical knowledge and lack of institutional support in terms of policy and infrastructure. This research was carried out to evaluate uptake by farmers of improved management practices (interventions) and their effect on performance of indigenous chickens at farm level and consequences for farmer participation in the implementation of research activities. The research involved 200 farmers in five regions in three counties. Four villages were selected per region and10 farms in each village. Interventions housing, feed supplementation, vaccination and deworming were implemented by farmers and monitoring and evaluation carried out. Farmers used own local inputs in implementing the project interventions and recorded various project activities and outputs. The project was monitored over a span of five, 3-months long periods. 25% of farmers in the entire five regions did not have housing as a treatment in any of 5 periods. Feed supplementation had high level of use by all farmers in each period. More farmers applied deworming in later periods, 25% had vaccination in period 1, and 40% in period 5. Periods 3 – 5 generally seem to be the time most applications were done. Flock sizes rose from 10 – 20 birds per farm to 20 – 30. Farmer participatory research is a tool for technology testing and transfer and a quick and effective means of generating and disseminating information.
Evaluation of lambda-cyhalothrin persistence on different indoor surfaces in a malaria epidemic-prone area in Kenya.
(Medwell online, 2010) Mulambalah, CS.; Siamba, Donald N.; Ngeiywa, MM.; Vulule, JM.
The residual life of pyrethroid insecticide lambdacyhalothrin (trade name: ICON) on indoor surfaces was evaluated under field conditions in villages in a highland area of Kipsamoite, North Nandi District of Kenya. About 10% lambda-cyhalthrin wettable powder was sprayed at the rate of 0.02-0.03 g m-2 on the indoor wall surface of randomly selected local houses. Its effect on mortality of Anopheles gambiae s.s as test vector was assessed from January to April 2007. Wall bioassays were conducted on different treated wall surfaces using plastic cones attached to treated surfaces at fortnightly intervals. Mortality rate in mosquitoes exposed to treated surfaces varied according to the type of wall that received the insecticide. ICON was more stable and lasted longer on mud and wood surfaces. There was significant difference between persistence of ICON on mud and other surfaces tested. For the insecticide formulation used, the duration of the residual effect was satisfactory up to the WHOPES recommended post spray period. Beyond this period, persistence declined rapidly on metal and cemented/brick plastered surfaces. The low effectiveness of the formulation on metal and cement surfaces should be considered together with the importance of residual spraying as a vector control method in the area. We concluded that the use of ICON in IRS could be a single and effective strategy to control endophiliic and antropophilic malaria vectors in malaria hypoendemic area. This is based on the findings that the local vector is susceptible to ICON and most of the houses had mud surfaces and malaria transmission is seasonal. In this regard, one round of ICON spray would be sufficient to interrupt 3-4 month seasonal malaria transmission in the study area. Apart from its toxicity to mosquitoes, ICON also agitates and repels mosquitoes that do not come in contact with it and therefore an added benefit of reducing the indoor malaria vector densities. This would drastically reduce human-vector contact and overall decline in community malaria prevalence.
Exsheathment characteristics and infectivity of revived anhydrobiotic L_ (3) of haemonchus contortus
(Maxwell science, 2012-10-20) Siamba, Donald N.; Mulambalah, CS.; Ngemaeiywa, MM.; Gatongi, PM.; Wamae, LW.
This study was conducted to determine the effect of temperature and moisture stress on exsheathment process and infectivity of the infective larvae of the parasitic nematode ＂Haemonchus contortus＂. Laboratory conditions were used in which infective (L_(3)) of ＂H. contortus＂ were either subjected to gradually increasing temperatures, decreasing moisture or both. Post stress viability and exsheatment of L_(3) was determined prior to infection experiments. The viability of ＂H. contortus＂ after induction of anhydrobiosis declined significantly (p＜0.05) from 85 to 60% in about 60 days. The results showed significant (p＜0.05) delay in exsheathment in stressed larvae compared to unstressed larvae leading to low overall establishment (Infection). However, the proportion of the immature in relation to the mature parasites (hypobiosis) was significantly (p＜0.05) higher in stressed compared to the unstressed L_(3). These results indicate that delayed exsheatment in stressed L_(3) contributes to low infectivity in ruminants.
Heavy metal contamination at dumpsites at Eldoret, Kenya, in the lake victoria basin
(East african literature bureau, 2018) Khatiebi, Sandra.; Siamba, Donald N.; Onyando, Zedekiah.; Mulmbala, Chrispinus.; Konje, Martha.
This study assessed the heavy metals concentrations in municipal solid wastes at Eldoret Mwenderi dumpsites located at the shores of river Sosiani within the Lake Victoria Basin, Kenya. Concentrations of the three heavy metals analysed (lead, arsenic and cadmium) in water and leachate were higher than the WHO acceptable standards. Lead concentrations in solid wastes were slightly above East African acceptable standards but well above the US EPA compost standards. The wastes dumped in this site are not sorted and the dumpsite lacks a leachate collection and removal system. Lack of composite liners at the bottom and side of the dumpsite allow leachates to move into the ground water around the dumpsite. These metals are a potential threat to Lake Victoria and regular monitoring of ground and surface water of the surrounding area should be done to detect any heavy metals escaping the dumpsite.
Implications of mycotoxin contamination of dairy feeds and products
(KARI publication unit, 2014) Lanyasunya, TP.; Lokwaleput, IK.; Mutunga, TK.; Siamba, Donald N.; Ondiek, JO.
The complex diet of ruminants, consisting of forages, concentrates, and preserved feeds, can be a source of very diverse mycotoxins that contaminate individual feed components. A number of mycotoxins are successfully inactivated by the rumen flora, whereas others pass unchanged or are converted into metabolites that retain biological activity. Hence, the barrier function of the rumen largely determines the susceptibility of dairy cows and other ruminant species towards individual mycotoxins. An impairment of this barrier function due to diseases or the direct antimicrobial effect of certain mycotoxins may increase absorption rates. The rate of absorption determines not only the internal dose and risk for adverse health effects, but also the excretion of mycotoxins and the biologically active metabolites into milk.
Improved cow fertility through appropriate management practices on-farm in Koibatek and Nakuru districts
(KARI, 1999) Siamba, Donald N.; Lokwaleput, I.; Jong, Rde.
n a survey conducted in 1996, 82 (22.6 percent) of all cows with impaired fertility, i.e expected calving interval over 1.5 years, were found on 63 and 53 farms in Koibatek District and Nakuru District (Bahati Division), respectively. The cows were appraised visually for body condition, and rectal palpation was done to determine the condition of their reproductive organs. The appraisal revealed that about 50 percent of the cows were in poor condition and about 60 percent were in anoestrus, thus indicating the effect of nutrition. Work carried out earlier in Kiambu, Nyandarua and Nakuru Districts of Kenya on factors causing impaired fertility in cows on-farm, showed that management factors and most importantly, nutrition was the primary cause