UNAM Gā-aisib Repository
The UNAM Gā-aisib Repository serves as a central platform to preserve and showcase the university's scholarly output.
Communities in the Gā-aisib Repository
Select a community to browse its collections.
Recent Submissions
Quantification and characterization of nutrients in Senegalia mellifera milled biomass, feed intake and nitrogen balance in female Boer goats fed with Senegalia mellifera bush-based feeds
(International Journal of Agricultural Research and Review, 2024) Epafras, A.; Mupangwa, Johnfisher; Charamba, Vonai; De la Puerta, M. L. F.
The objectives of this study were to quantify and characterise the nutritional content of milled
Senegalia mellifera milled biomass obtained from nine blocks at Neudamm Farm and to determine the dry
matter intake (DMI), apparent digestibility and nitrogen retention in female Boer goats fed with Senegalia
mellifera bush based feeds. Wood ash (WA), polyethylene glycol (PEG, 6 000) and biochar were evaluated as
tannin deactivation methods. The milled biomass of S. mellifera was mixed using a clean concrete mixer with
the following ingredients: yellow maize meal, liquid molasses; Marula oil press cake and coarse salt to
formulate a complete diet with 14% CP and 11MJ ME/kg. Detannification treatment methods were added at
a level of 5 g per day during feeding time. We used eight (8) female Boer goats weighing an average of 31.5
kg (± 2.5 kg) for the feeding experiment. We penned the goats individually in metabolic cages. Clean water
was available ad libitum to the goats during the entire feeding experiment. The goats were fed in a 4x4 cross
over Latin square design with four periods of experimental feeding. Each period lasted for 17 days, resulting
in 68 days of experimental feeding. The goats were fed twice daily at 09:00h and 16:00h. The level of dry
matter (DM) of feed offered was 4% of body weight. The results obtained in this study showed that there
was a significant difference (p <0.05) in the chemical composition of Senegalia mellifera milled biomass
harvested from the nine blocks at Neudamm Farm. The CP content of Senegalia mellifera milled biomass
ranged from 9.39 to 9.68 %DM while the NDF and ADF ranged from 59.17 to 64.33%DM and 43.77 to
48.01%DM, respectively. The condensed tannins (CT) content from all blocks did not differ (p >0.05) and had
a mean of 0.02 to 0.03%DM as leucocyanidin equivalent (LE Absorbance at 550 nm). The apparent digestibility
coefficients of DM, OM and NDF were not significantly different among treatments and the control diet (p
>0.05). Goats fed biochar treated diet had the highest nitrogen intake of 13.74g/d (p <0.05), faecal nitrogen
of 8.43g/d (p <0.05) and nitrogen retention of 5.11g/d (p <0.05), while goats fed the control feed (CNT), PEG
and WA were similar (p >0.05). All treatments resulted in a positive nitrogen retention (p >0.05) with mean
values ranging from 3.79 to 5.11 g/d. The study concluded that, there was a significant difference (p <0.05)
in the chemical composition of S. mellifera milled biomass collected from nine blocks at Neudamm Farm.
Given the high CP content of the S. mellifera, this fodder resource can be considered a suitable supplement
for poor quality (low N content) natural pastures and crop residues such as grass hay, straw and stover. The
study also concluded that, there was a significant difference (p <0.05) in the DMI, and nitrogen balance in
Boer goats fed with A. mellifera feeds treated with Wood ash (WA), Polyethylene glycol (PEG, 6 000) and
Biochar (BIO). The study therefore recommends that each detannification method should be tested at
different rates of inclusion in S. mellifera bush based feed resources
Utilising encroacher bush in animal feeding
(Springer, 2023) Mupangwa, Johnfisher; Lutaaya, Emmanuel; Shipandeni, Maria Ndakula Tautiko; Kahumba, Absalom; Charamba, Vonai; Shiningavamwe, Katrina Lugambo
Livestock production is a major economic and livelihood activity in
Namibia which contributes at least 75% to total agricultural output. The industry
faces challenges including prolonged droughts, increased production costs, bush
encroachment, variable climatic conditions and disease outbreaks. Bush encroachment and prolonged drought spells pose a major concern as they result in reduced
carrying capacity of rangelands. The encroacher woody browse plants are potential
animal feeds as they provide considerable amount of biomass from leaves and small
twigs as well as pods that provide nutrients to ruminant livestock during the long dry
season. Converting the biomass from the encroacher bushes into livestock fodder is
one best management practice of controlling bush encroachment while increasing
the availability of ruminant feeds sustainably without competing with human food
production. Our chapter provides data on the nutritional content of encroacher
bushes in different seasons and feeding value of bush-based feeds as an alternative
feed resource for ruminant livestock. The chapter presents the opportunity and
evidence that shows that utilising encroacher bush-based feeds in ruminant livestock
feeding results in animal growth and the production of quality carcasses that
contribute to human protein food. We conclude that the utilisation of rangeland
encroacher bush species in sub-Saharan Africa in bush-based feeds provides sufficient nutrients to support improved ruminant livestock production and contributes to
rangeland ecosystems restoration
Climate change adaptation strategies among smallholder livestock farmers in Namibia's Omaheke Region, Namibia
(Discover Sustainability, 2025) Siririka, Ndjipua Avihe Tjaondjo; Charamba, Vonai; Mupangwa, Johnfisher; Shipandeni, Maria N. T.; Kahumba, Absalom
The challenges of climate change are continuously increasing, constituting a major threat to livestock production, which
is more than a socio-economic cornerstone in Namibian rural communal farmers, contributing approximately two-thirds
of the country’s agricultural GDP. Climate variability, which may be in the form of drought, very high temperatures, floods
and frosts has been reported to have detrimental effects on feed and water availability, leading to reduced livestock
weight, growth, production and reproductive performance, and ultimately high mortality. Understanding smallholder
farmers’ socio-psychological antecedents such as knowledge, attitudes and perceptions and the way they influence their
level of adaptation to CC mitigation strategies needs to be assessed, as it guides CC policy formulation and intervention
programmes. The study investigated CC perception and adaptation strategies for livestock farmers in Omaheke Region.
Data were gathered from (n=80) purposively sampled farmers in Epukiro and Otjombinde constituencies based on
livestock ownership. The study revealed that 93.8% of the respondents were aware that the climate is changing, with
attributes such as very high and very low temperatures, high and low rainfall, and drought having been noticed. Climate
change has been attributed to both human and natural activity. The study observed that the implementation of CC
adaptation strategies in livestock agriculture is low, thus recommends that the improvement of adaptation techniques
involving employing extension services, promotion of farmer-to-farmer extension, and utilization of various information
sources of climate knowledge, such as farmers’ associations and social organizations, should be the future policy priority
Indigenous knowledge of browse species and nutritional quality of dominant indigenous browse species in the Kavango West Region of Namibia
(Discover Sustainability, 2024) Hamukwaya, Rosa N.; Charamba, Vonai; Kahumba, Absalom; Shipandeni, Maria N. T.; Mupangwa, Johnfisher
Livestock production is crucial to the livelihoods of rural Namibians but highly constrained by feed shortages due to
climate change and bush encroachment. The study investigated the grazing and feeding practices and indigenous
knowledge of browsable and non-browsable species by interviewing 30 small-scale farmers in the Kavango West Region.
It assessed the nutritive value for the three most commonly identified browsable species. The study observed that
livestock relies on communal rangeland, roadside, and riverside grazing, with supplements from crop residues during
the dry seasons. However, most farmers experience feed shortages mainly in the dry season, which results in decreased
livestock productivity. Farmers are knowledgeable on browsable and non-browsable woody species in their locality, but
most do not harvest pods, leaves and twigs to supplement their animals in the dry season, citing labour shortage, and
they are not aware that the bush species resources can be harvested and be used during seasons when feed resources are
scarce. The nutritive value analysis indicated that there is a need for strategic supplementation of the browsable species
for them to be effectively utilised as livestock feed, thus farmers must be capacitated on when and how to utilise these
species when herbaceous pasture grasses and legumes are senescent as well as how to harvest forage alongside rivers
and roads for stall feeding to avoid accidents. Our findings will be important for policy formulation in trying to come up
with better ways of mitigating the consequences of climate change
Phytochemical content, antibacterial, antioxidant and cytotoxic activities, of leaves extracts of Eucalyptus globulus, Peltophorum africanum and Vangueria infausta
(Discover Agriculture, 2024) Moshidi, Portia Mamothaladi; Mupangwa, Johnfisher; Muya, Claude Mukengela; Washaya, Soul
This study aimed to determine the extraction yield, phytochemical content, antibacterial, antioxidant, and cytotoxic activities of leaves extracts from Eucalyptus globulus, Peltophorum africanum, and Vangueria infausta. Leaves were harvested, separated from the stems, and dried for chemical analysis. Crude and oil extraction, antioxidant activity, cytotoxicity, and minimum inhibitory concentration were determined, and tannins, flavonoids and alkaloids were quantified by standard protocols. The phenolic, flavonoids, and condensed tannin contents were higher (P < 0.05) in V. infausta extract than in E. globulus and P. africanum. The radical scavenging activities were higher (P < 0.05) in V. infausta, E. globulus than in P. africanum. The antibacterial activity was lower (P < 0.05) for P. africanum and E. globulus oil, and was strongly related to the presence of phenolics and flavonoids. The lack of toxicity of plant extracts suggests that extracts can be used as animal feed additives with no risk of toxicity. Vangueria infausta, Eucalyptus globulus had the highest antioxidant capability and can thus modulate nutrient metabolism in animals
Effects of feeding incremental levels of Spirulina platensis on feed intake and growth performance of Boschveld and Potchefstroom Koekoek chicken breeds
(Discover Agriculture, 2024) Nambahu, Aino; Petrus, Ndiilokelwa Patricia; Mupangwa, Johnfisher; Charamba, Vonai; Lutaaya, Emmanuel
spirulina is increasingly being used in feed manufacturing because of its high nutritional value, especially proteins, for
humans and animals. This study examined the feed intake and growth performance of Boschveld and Potchefstroom
Koekoek chicken breeds when soybean meal was substituted with incremental levels of Spirulina platensis. The experimental design was a 2×4 factorial with repeated measures over a 12-week period, with breed and diet as factors. The
experimental unit was a cage holding 3 birds, with 3 cages allocated to each breed-diet combination, hence 36 birds per
breed. The diets were: 0%, 5%, 10% and 15% using dried Spirulina platensis powder to replace soybean meal per 100 kg
of feed. Chickens fed control diet consumed more (P<0.05) feed than those fed Spirulina-containing diets. Diet affected
(P<0.0001) final weights (g) of the birds which were 1093.2, 921.6, 762.8 and 771.2 for 0%, 5%, 10% and 15% inclusion
levels of Spirulina platensis, respectively. Boschveld chickens had better average daily gain compared to Potchefstroom
Koekoek at week 15–16. Averaged over the 12 weeks, the control diet gave better (P<0.0001) average daily gain (9.42 g/d)
than the Spirulina-containing diets. Over the 12 weeks, the control diet had a more desirable (7.79 vs. 8.17, P=0.01) feed
conversion ratio than the Spirulina-containing diets Spirulina at a level of 5–10% can be used as a protein supplement
in indigenous chicken feeds because it resulted in growth performance close to control diets
Nutritional assessment of three baled rice straw varieties intended for use as ruminant feed in Namibia
(Cogent Food & Agriculture, 2021) Madzingira, Oscar; Hepute, Venaune; Mwenda, Evelyn Nanjeke; Kandiwa, Erick; Mushonga, Borden; Mupangwa, John F.
This study determined and compared the proximate and chemical composition of Angola, IRGA 418 and SUPA rice straw varieties harvested and baled in 2016 and 2017. In both 2016 and 2017, SUPA straw had the highest dry matter (DM) content (960.7 ± 0.50 g/kg and 939.4 ± 0.10 g/kg), neutral detergent fibre (NDF) (575.2 ± 9.90 g/kg and 594.7 ± 9.00 g/kg), acid detergent fibre (ADF) levels (374.7 ± 6.30 g/kg and 379.9 ± 9.90 g/kg) and cellulose (CL) content. Angola straw had the highest crude protein (CP) content (39.1 ± 2.00 g/kg, p < 0.05; 60.7 ± 2.70 g/kg) and acid detergent lignin (ADL) concentration (p < 0.05) in both years. Organic matter (OM), hemicellulose (HC), ash, fat and mineral content varied with year in all rice straw varieties. Angola straw had the lowest metabolisable energy (ME) of the three straw varieties. All straw varieties were deficient in at least one or more essential nutrient components. Nutritional and chemical composition varied with rice straw variety, year of cultivation and baling. Therefore, pre-treatment to improve digestibility and supplementation of deficient nutrients is recommended for effective use as ruminant feed. IRGA 418 straw was recommended as the best choice for ruminant feeding based on higher digestibility (IVOMD) and ME values
A hierarchical non-parametric Bayesian testlet model for dual local dependence
(University of Namibia, 2021) Charamba, Vonai; Kazembe, Lawrence
The use of psychometric tests to measure the level of individuals on unobservable traits
is common in many fields and item response theory (IRT) models are usually used for
proficiency measurement. Standard IRT models assume local person and item independence and normality assumption for the true ability distribution. However, respondents
are often clustered and test items are often grouped according to sub-content measuring
the same stimuli or sub-component of the trait. This study presents a non-parametric
polytomous multilevel testlet model for simultaneously modelling person and item clustering effects. The grouping variable is assumed unknown and determined from the
data using the Dirichlet Process. The model was compared with a parametric dual
model with groups assumed to be known, the testlet model, the Generalised Partial
Credit Model and the multilevel model accounting for person dependence effects only
in terms of systematic, random and total errors in person and item parameter estimation and test information and reliability, for simulated and real life data. The
effects of ignoring dual dependence effects were evaluated for variant group, sample,
testlet size, number of response options and mixed items tests. Groups of size 5, 20
and 40 were compared for 400, 1000 and 2000 respondents. The effects of ignoring
dependence effects were compared for 6 testlets of 3, 6 and 10 items each for 3, 4
and 5 response categories were compared. Consequences of mis-specifying the slope
and proficiency distributional parameters were evaluated where the competing models
estimated item and person parameters for skewed, bimodal, normal and uniformly distributed traits and constant and stochastic slopes. Three dependency conditions (0,
xi
none; 0.5, medium; 1, large), were considered for both local item dependency (LID)
and local person dependency (LPD). For each simulation study, a fully-crossed factorial
design was employed and the general linear model was employed for comparing estimation errors. Significant different means were detected by use of Cohen’s effect size,
f. In general, ignoring LPD effects resulted in increased bias and total errors in the
estimation of ability parameters while ignorance of LID negatively impacted on item
parameter estimation increasing with sample size, testlet size and number of options.
Failure to account for LID resulted in underestimation of proficiency standard errors,
thus resulting in overestimation of test information and reliability. When dual dependence effects were ignored, both item and ability parameter estimation accuracy was
reduced. The non-parameter model detected the number of groups and group membership well especially for smaller groups, increasingly with sample size, testlet size
and number of categories. However, the non-parametric models requires high computational performance Considering the consequences of ignoring random effects and the
computation efficiency required by the non-parametric model, it is recommended that
the model be used to detect dependence effects and groups, and standard IRT models
be applied for independent persons
Foliar nutrient content responses to bio-inoculation of arbuscular mycorrhizal fungi and Rhizobium on three herbaceous forage legumes
(Frontiers, 2023) Mpongwana, Sanele; Manyevere, Alen; Mupangwa, Johnfisher; Mpendulo, Conference Thando; Mashamaite, Chuene Victor
Smallholder livestock production in the Eastern Cape Province of South Africa has been hampered by a lack of high-quality feed. As such, improving ruminant nutrition using optimized production of herbaceous forage legumes has been suggested. However, the production of forage legumes for livestock feed is poor in communal areas in the province due to the necessity to use high levels of chemical fertilizers to provide high-quality feed that meets animal nutrient demands. The current study aimed at investigating the effects of arbuscular mycorrhizal fungi (AMF) and Rhizobium inoculation on the chemical composition of three herbaceous forage legumes, namely, Vigna unguiculata (cowpea), Lablab purpureus (lablab), and Mucuna pruriens (mucuna). The field trials were established over two growing seasons (2017/2018 and 2018/2019) at the University of Fort Hare Research Farm (South Africa) and were carried out as a 3 x 2 x 2 factorial experiment arranged in a randomized complete block design (RCBD) with 12 treatments that were replicated 4 times. The 12 treatments included three legume species (cowpea, lablab, and mucuna), two AMF (with and without AMF inoculation), and two Rhizobia inoculations (with or without). The results showed that the dual inoculation of AMF and Rhizobia bacteria significantly (p < 0.05) increased the contents of crude protein, neutral detergent fiber and acid detergent fiber, hemicellulose, ash, magnesium (Mg), phosphorus (P), calcium (Ca), zinc (Zn), and iron (Fe) of three herbaceous forage legumes. Furthermore, solo inoculation with AMF or Rhizobia bacteria resulted in substantially higher potassium (K), Ca, and Mg cation ions, and Ca/P, Zn, manganese (Mn), and Fe concentrations in forage legumes than in other treatments. In conclusion, the dual inoculation produced optimal nutrient accumulation in both growing seasons when compared to single inoculation and uninoculated forages. Therefore, this could assist in alleviating livestock malnutrition in smallholder farming
Exploring the hurdles of implementing National School Health Policy in Namibian Schools: Insights from stakeholders
(BMC Health Services Research, 2025) Katangolo-Nakashwa, Ndasilohenda; Mfidi, Faniswa Honest
This qualitative research study explores stakeholders’ perspectives on the challenges of implementing Namibia's National School Health Policy (NSHP) in schools. The interview guide used for this study was specifically developed to address the research objectives and themes. A total of 20 stakeholders participated, including educators, nurses, principals, and health program administrators from three regions in Namibia. The study identifies significant barriers to effectively implementing the school health policy. These barriers include staffing shortages, inadequate resources, limited learner awareness of health rights, and insufficient teacher well-being. Additional challenges involve resource constraints, a lack of monitoring and evaluation, and limited coordination between the education and health sectors. The thematic analysis reveals recurring patterns and emphasizes the need for increased resource allocation, comprehensive training, collaborative policy development, and initiatives to improve teacher well-being. These findings provide valuable insights for refining future implementation strategies for school health programs in Namibia, highlighting the importance of strong leadership, stakeholder involvement, and adequate funding to support the goals of the NSHP