Welwitschia International Journal of Agricultural Sciences
type: channel
description: Welwitschia International Journal of Agricultural Sciences (WIJAS) is a diamond open access journal of the University of Namibia, that publishes original and review papers, surveys, experiments, case studies, technical reports, viewpoints, book reviews, notes, commentaries and news in various agriculture and natural resources disciplines. Journal maintains high-quality publication of manuscripts that meet the general criteria of scientific excellence.
publisher: University of Namibia
language: en
publication name: Welwitschia International Journal of Agricultural Sciences
issn: 2026-8750
copyright: The Welwitschia International Journal of Agricultural Sciences (WIJAS) is published under a Creative Commons Attribution 4.0 (CC BY 4.0) license. The license allows users to distribute, remix, adapt, and build upon the material in any medium or format, provided that attribution is given to the creator. The license also allows for commercial use. The WIJAS has migrated from a CC BY-NC 4.0 license to a CC BY 4.0 license to allow for further sharing and re-use of knowledge with no restrictions.
items: Characterization of the nutritional values of agro-industrial by-products in Namibia as potential supplements of the bush-based feeds
items: Public Spending as a Predictor of Livestock Total Factor Productivity in Namibia
items: Modelling supply response and volatility of Swakara pelts in Namibia
items: Feed intake, growth performance, carcass characteristics and organ sizes of broilers fed baobab seed oilcake supplemented finisher diets
items: Genetic and non-genetic factors influencing birth weight in the Tuli cattle breed of Zimbabwe
items: Mammal species composition and diversity of the Nyae Nyae Communal Conservancy, Otjozondjupa Region, Namibia
items: Evaluation of Musca domestica (House fly) larvae production from organic waste
items: Characterising the trophic relationships between cuttlefishes, myctophids and round herring in the Northern Benguela
items: Structure of avian communities in a mosaic of built-up and semi-natural urbanised habitats in Katima Mulilo town, Namibia
items: Rainfall trend and variability in semi-arid northern Namibia: Implications for smallholder agricultural production
items: Modeling and comparison of the maturing rates of Damara, Dorper and Swakara sheep at Neudamm Farm
items: Evaluation of pre-emergence herbicides for weed control in maize
items: Drivers of profitability in the Namibian cattle farming: A case study of north western Namibia
items: Spatio-temporal variation in length-frequency and salinity tolerance of dominant fishes utilizing the Orange River-Estuary Continuum
items: https://journals.unam.edu.na/index.php/WIJAS/article/view/1408
items: A cross sectional comparison of chemical treatment on plant biodiversity at Neudamm farm, Namibia
items: A survey of the usage and storage practices of veterinary medicines among communal cattle farmers in the Kabbe South Constituency, Zambezi region.
items: Polymorphism of the KAP1.3 and KRT33A genes in the Swakara sheep of Namibia
items: Effect of legume hay supplementation on feed intake, growth, digestibility and volatile fatty acid production of Xhosa goats
items: Agronomic and morphological diversity of Bambara groundnut (Vigna subterranea (L.) Verdc.) accessions in North-Central Namibia
items: The effect of arboricide application on soil chemical properties at Neudamm farm, Namibia

Characterization of the nutritional values of agro-industrial by-products in Namibia as potential supplements of the bush-based feeds
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description: The objective of this study was to characterize the nutritional values of Namibian agro-industrial by-products (AIBPs) as potential supplements for bush-based feeds. Fourteen AIBPs’ samples were collected from Namibian local cereals and oilseed processing companies. Cereal by-products were malt dust fine (MDF), pearl millet bran (PMB), malt dust coarse(MDC), white maize chop (WMC), wheat bran(WB), brewer’s spent grains(BSG), sorghum brew residue (SBR) and sorghum spent grains (SSG), while oilseed byproducts were olive oil cake(OIC), marula oil press (MOP), jojoba oil cake (JOC), !nara oil cake(NAC), manketti oil cake (KOC) and marula oil cake (MOC). Chemical compositions, in vitro gas production, in vitro organic matter digestibility, and metabolizable energy of the AIBPs were determined in a randomized complete block design and the data were statistically analyzed using a Statistical Package for Social Science. Crude protein, ether extract, neutral detergent fiber, and acid detergent fiber ranged from 7.90 (SSG)-21.95 %( BSG), 1.37(MDF)-9.29%(PMB), 22.23(WMC)-73.06%(BSG), 7.22 (PMB) -30.46% (BSG) respectively for cereal by-products and 7.55(OIC)-37.3% (MOP), 8.11(KOC)-53.55%(MOC), 11.40 (MOC)-58.26%(KOC) and 8.21(MOP)-52.26%(MOP) in oil seeds by-products respectively. The in vitro gas production, in vitro organic matter digestibility, and metabolizable energy ranges for cereal and oilseed by-products were 31.50 (BSG)-70.20ml/200mgDM(WMC), 55.55 (BSG)-83.50%DM(WMC), 9.30(BSG)-14.00MJ/Kg(white maize chop), and 3.80 (MOP)-35.30ml/200mgDM(jojoba oil cake), 38.95(MOP)-59.35%(JOC), and 7.45(MOC)-15.95MJ/Kg(MOP), respectively. The AIBPs investigated in this study comprised of minimal fiber contents, adequate crude protein, and metabolizable energy contents above minimum requirements for ruminant animals. However, promotion to maximally utilize these AIBPs in animal diets requires further evaluation.
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creator: Magdalena Kamati
creator: Johnfisher Mupangwa
creator: Maria N. T Shipandeni
rights: Copyright (c) 2022 Magdalena Kamati, Johnfisher Mupangwa, Maria N. T Shipandeni https://creativecommons.org/licenses/by-nc-nd/4.0
date: 2022-09-11
publication date: 2022-09-11
starting page: 11
ending page: 22

Public Spending as a Predictor of Livestock Total Factor Productivity in Namibia
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description: This paper investigates public spending and its catalytic role towards a productive agricultural sector. This was done empirically by testing how agricultural total factor productivity could be increased. Data used is for the period 1991 to 2021. A Tornqvist-Theil Index was developed. A simultaneous equation became the chosen and implementable analytical tool for this study. While an agricultural total factor productivity index for Namibia did not exist before, the livestock component was generated for the first time in this study to fill this gap. Stunning is the fact that the Malabo declaration in terms of its convergence target of 10% is not yet met. The results show that by increasing productive labour to the livestock subsector by 10%, real gross domestic product will increase by 12%. Likewise, should capital formation and spending towards agriculture be increased to 10%, the growth of the agricultural sector will increase by 8.5%. This would require input-base needs to be expanded for output to increase. The work done by the Namibian Government so far yearn for further efforts to create more jobs, increase food production, and foreign income earning, remains to be addressed. To achieve all these, compliance with the Malabo declaration would be necessary.
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creator: Helmke Jens Sartorius von Bach
creator: Jacob Nyambe
rights: Copyright (c) 2022 Helmke Jens Sartorius von Bach, Jacob Nyambe https://creativecommons.org/licenses/by-nc-nd/4.0
date: 2022-09-11
publication date: 2022-09-11
starting page: 23
ending page: 36

Modelling supply response and volatility of Swakara pelts in Namibia
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description: The karakul industry has been experiencing a continuous decline in the number of pelts supplied since the late 1970s. This decline is speculated to be a result of the anti-fur movement. Coincidently, throughout the years, the price of Karakul pelts is seen to increase. This abnormal mismatch in supply and demand has challenged economic theory which explains that price increases should increase supply. This paper uses time-series data from 1960 to 2019 to model supply response and volatility in the karakul industry. The dataset was tested for unit root and an autoregressive distributed lag model was run to examine the extent to which the local production of Swakara pelts responds to the supply determinants. Pelt supply lagged one year, cost of production, average pelt producer price, average mutton producer price yield, and the exchange rate has significant implications on the current pelt supply. The influence of the anti-fur movement, however, equally has a significant relationship. The results indicated high volatility between all variables with social awareness being the outlier. The global anti-fur movement has played a large role, that Namibian farmers reduced their Karakul stock. Since 2012, nationally but also globally, prices of all pelt and fur are on a continuous decline which points to a “dying” industry. The survival of the Namibian pelt industry requires further research on the global demand, adjustments of some legislation, and supported production incentives for farmer welfare.
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creator: Leigh-Ann T Nehoya
creator: Kennedy Kalundu
creator: Helmke Jens Sartorius von Bach
rights: Copyright (c) 2022 Leigh-Ann T Lehoya, Kennedy Kalundu, Helmke Jens Sartorius von Bach https://creativecommons.org/licenses/by-nc-nd/4.0
date: 2022-10-03
publication date: 2022-10-03
starting page: 50
ending page: 63

Feed intake, growth performance, carcass characteristics and organ sizes of broilers fed baobab seed oilcake supplemented finisher diets
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description: Baobab (Adansonia digitata L.) seed oilcake has been proven a potential low-cost and locally available protein source for various livestock diets. A study was conducted to determine growth performance, carcass characteristics and organ sizes of finisher broilers fed a commercial finisher diet supplemented with baobab seed oilcake. Three-week-old ROSS 308 broiler chicks (n = 160) that were reared on a starter and grower commercial diets for the first three weeks were allotted to one of four broiler finisher dietary treatments (10 chicks/pen, four replications/treatment) using a completely randomised design. The broiler finisher diets were: control diet, which was a commercial finisher diet (T1), T2 contained 6 g/kg baobab seed oilcake plus maize mash (BSOCMM) mixed with 114 g/kg commercial finisher diet; T3 contained 18 g/kg BSOCMM mixed with 102 g/kg commercial finisher diet; while T4 contained 30 g/kg BSOCMM mixed with 90 g/kg commercial finisher diet. There were no significant (P > 0.05) differences in the growth parameters among the treatments. However, the birds on T2 had a higher feed conversion ratio and average daily gains. Final body weights at day 35 were not significantly (P > 0.05) different, but T3 and T4 birds had the highest values numerically. There were significant (P < 0.05) differences in the carcass weights and dressing percentages among the treatments. The T4 birds had the highest dressing percentage (P < 0.05) compared to T2, which had the lowest. The cut portion yield (thigh, wing, breast and feet) of the carcass were not significantly (P > 0.05) different among the treatments. However, the drumstick yield was significantly (P < 0.05) different among the treatments. Organ sizes showed no significant (P > 0.05) differences among treatments, except for the gizzard and the heart, which differed (P < 0.05) among treatments. The study concluded that the inclusion of 6–30 g/kg of BSOC blended with maize mash as partial supplementation to a commercial…
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creator: P Chisoro
creator: T Nkukwana
creator: J Mupangwa
rights: Copyright (c) 2019 Welwitschia International Journal of Agricultural Sciences
date: 2019-12-13
publication date: 2019-12-13
starting page: 26
ending page: 34
doi: 10.32642/wijas.v1i0.1358

Genetic and non-genetic factors influencing birth weight in the Tuli cattle breed of Zimbabwe
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description: Genetic and non-genetic factors were estimated for birth weight in the Tuli cattle breed of Zimbabwe. Performance records ( n = 1154) were obtained from the Livestock Identification Trust (LIT) for the period (2008–2014) for three farms; X ( n = 494), Z ( n = 143) and Y ( n = 517). We used the Restricted Maximum Likelihood (REML) for fitting the Sire model. The model used the farm, season, sex, year and dam age as fixed effects while the sire was fitted as a random variable. Best Linear Unbiased Prediction (BLUP) was used to predict breeding values (BVs). The mean birth weight was (30.89±0.128). Wet season had higher birth (31.62±0.27) weight than dry season (30.62±0.144); however, the difference was not statistically significant. The other factors, farm, sex, year and dam age had a significant effect (P <0.05) on birth weight. Heritability and repeatability estimates were 0.44 and 0.35, respectively. Based on the results, the high heritability estimate for birth weight suggests that the trait responds well to selection. Sire breeding values ranged from -4.400 to 6.845 with the majority of sires between -2 and 2, showing that there was stabilising selection over the years to minimise both overweights and underweights.
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creator: T Magwaba
creator: M Sungirai
creator: K Hove
creator: S K Awala
rights: Copyright (c) 2019 Welwitschia International Journal of Agricultural Sciences
date: 2019-12-13
publication date: 2019-12-13
starting page: 49
ending page: 58
doi: 10.32642/wijas.v1i0.1359

Mammal species composition and diversity of the Nyae Nyae Communal Conservancy, Otjozondjupa Region, Namibia
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description: The emergence of the communal conservancies in Namibia contributed to community-based conservation approach outside protected areas. This study was conducted to establish the status of biodiversity conservation of the Nyae Nyae Conservancy by analysing the mammal species composition and diversity changes for 13 years. The long-term wildlife count data were obtained from the conservancy in Tsumkwe, Otjozondjupa region. A total of 20 mammal species, comprising of ungulates and predators, were recorded from 2001 through 2013. The overall trend of the mammal species population sizes was positive, though not statistically significant (r = 0.477; t10 = 1.574; P = 0.145). In addition to the stable species composition over the years, the mammal species diversity in Nyae Nyae conservancy was high (Simpson Index of Diversity, SID = 0.81). However, a significant decline in the diversity of mammal species (SID = 0.72) was detected in 2013 evident from the low species count data. This low diversity may be attributable to many factors including but not limited to the effects of severe drought which may have led to the emigration of some species, reduction in the abundance of some species due to deaths from drought and low reproductive output. Hence Nyae Nyae Conservancy, though an open unfenced system, serves as a good example in which a community-based natural management program outside protected areas contributes not only to the conservation of natural resources including wildlife but also utilisation of these resources for the benefit of local community members.
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creator: S Lendelvo
creator: L Kazembe
creator: J Mfune
rights: Copyright (c) 2019 Welwitschia International Journal of Agricultural Sciences
date: 2019-12-13
publication date: 2019-12-13
starting page: 76
ending page: 87
doi: 10.32642/wijas.v1i0.1360

Evaluation of Musca domestica (House fly) larvae production from organic waste
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description: The objective of the study was to investigate the effect of organic waste (pig manure and chicken layer droppings) on the production of house fly larvae (HFL) and its nutritive value. A completely randomised design was used, with three treatments (pig manure, chicken layer dropping and equal combination of the pig and chicken excreta) replicated six times. The data for biomass reduction, larvae wet and dry weight, moisture, ash, crude fibre, crude protein, fat, calcium and phosphorus were analysed using analysis of variance. While the least square means were generated using the Tukey's honestly significant difference. Pig manure produced the highest yield of HFL significantly (P < 0.05), as indicated by both wet (3.61 g) and dry (0.63 g) larvae weight. Introduction of HFL reduced organic waste by 39–42%. Furthermore, results indicated HFL to contain high protein 50-53%, considerable levels of Ca (1.32–1.465%) and P (1.72–2.09%) on as is basis. It can be concluded that pig manure and chicken layer droppings are suitable substrates for the production of HFL, which contain a suitable nutritional value for use as a protein source in animal diets. The study recommends further studies on HFL production on a larger scale for inclusion in animal diets.
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creator: T Uushona
creator: A Simasiku
creator: N P Petrus
rights: Copyright (c) 2021
date: 2019-12-29
publication date: 2019-12-29
starting page: 35
ending page: 40
doi: 10.32642/wijas.v1i0.1361

Characterising the trophic relationships between cuttlefishes, myctophids and round herring in the Northern Benguela
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description: Round herrings, myctophids, and cuttlefishes are a crucial part of the trophic interactions in the northern Benguela, as they form important trophic linkages between macrozooplankton and predators like hake, horse mackerel, and monk. The main objective of this study was to understand their trophic relationships using stable isotope measurements of their tissues. Tissues from round herring [Etrumeus whiteheadi], Myctophid species [Symbolophorus boops, Lampanyctodes hectoris, Diaphus hudsoni, Lampanyctus australis, Diaphus meadi], and cuttlefishes [Sepia australis and Sepia elegans] specimens were collected off Namibia. There were little variations in nitrogen stable isotopes (δ15N) values among these species, an indication that they fed at similar trophic positions. The trophic levels ranged from 2.51 to 3.00, an indication of their zooplanktivorous feeding habits. Among these species S. boops fed at a relatively higher trophic level, while L. hectoris fed at the lowest trophic level. Diaphus hudsoni had the lowest carbon stable isotope (δ13C) values and E. whiteheadi the highest. Significant differences were observed in δ13C values between most species, suggesting significant variations in their carbon sources. Isotope-based metrics showed overlapping trophic niches, with S. boops having a significantly broader niche. Our observations support the hypothesis that although these forage species have overlapping trophic niches, there are pronounced differences in the carbon sources of their prey.
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creator: V N Erasmus
creator: J A Iitembu
rights: Copyright (c) 2019
date: 2019-12-29
publication date: 2019-12-29
starting page: 59
ending page: 67
doi: 10.32642/wijas.v1i0.1362

Structure of avian communities in a mosaic of built-up and semi-natural urbanised habitats in Katima Mulilo town, Namibia
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description: A simplified mapping method has been employed to quantify avian assemblages in a plot with a mosaic of built-up areas (129 ha) and semi-natural or open areas (85 ha; grass, trees, shrubs) in the Katima Mulilo town, Namibia. Overall, 65 breeding bird species were recorded in the study plots (51 in the built-up areas, and 50 in the ‘open’ areas). Five of them, Rock Dove Columba livia, Grey-headed Sparrow (Passer diffuses), Dark-capped Bulbul (Pycnonotus tricolor), Laughing Dove (Streptopelia senegalensis) and Blue Waxbill (Uraeginthus angolensis) were classified as dominants. The cumulative dominance was 69.9% in the built-up area and 55.6 % in the ‘open’ area. The structure of the avian community in the built-up area was unexpectedly similar to that in the ‘open’ area. Almost the same number of breeding species was recorded, and almost identical diversity and evenness indices were calculated. However, the Sorensen Similarity Index was rather low (I = 0.69). Also, the overall density of all breeding birds was much lower in ‘open’ than in the built-up area. Granivorous birds were by far the most numerous feeding guild comprising in the built-up area 68.1% and in ‘open’ area 62.2 % of all breeding birds. Also, similar between the two areas compared was the proportion of granivores (17.7% vs. 19.7%) and insectivores (11.5% vs. 13.2%). These were also similar to the proportions of the main nesting guilds. Only the guild nesting in/on buildings was much higher in built-up than in the ‘open’ area. Although species richness was not high, population densities of some species were very high in the urbanised habitat. It is recommended to protect the larger specimens of marulas and other tree species in this habitat, as they play a vital role in maintaining the high population densities.
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creator: G Kopij
rights: Copyright (c) 2021 G Kopij
date: 2019-12-29
publication date: 2019-12-29
starting page: 68
ending page: 75
doi: 10.32642/wijas.v1i0.1363

Rainfall trend and variability in semi-arid northern Namibia: Implications for smallholder agricultural production
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description: Rainfall defines livelihood patterns among agrarian communities of the climate-change vulnerable semi-arid Sub-Saharan Africa. However, it remains inadequately studied, resulting in ineffective water management policies and weak agricultural growth in the region. Monthly rainfall data collected between 1987 and 2018 at four stations along a 1200 km climatic gradient in northern Namibia were analysed for annual, seasonal and monthly trends and variability. Descriptive measures and the Mann-Kendall test were used for rainfall characterisation and trend detection, respectively. Results showed an annually increasing rainfall trend, but with a downward trend in the dry season decreasing by -0.14 mm year–1 and an upward trend in the rainy season increasing by 7.74 mm year–1 across the study area. The rainy-season mean monthly rainfall showed predominantly increasing trends, while the dry-season ones exhibited insignificant decreasing trends. The study detected a decreasing rainfall gradient from the northeast towards the northwest with a range of 156.8 mm and concomitant increasing spatial-temporal variability. The upward rainfall trend has implications for rainy season floods, whereas the downward trend suggests dry season drought intensification in the area. These results could be useful for rainwater management planning in the study area and other dryland regions.
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creator: S K Awala
creator: K Hove
creator: M A Wanga
creator: J S Valombola
creator: O D Mwandemele
rights: Copyright (c) 2019
date: 2019-12-29
publication date: 2019-12-29
starting page: 1
ending page: 25
doi: 10.32642/wijas.v1i0.1364

Modeling and comparison of the maturing rates of Damara, Dorper and Swakara sheep at Neudamm Farm
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description: Although sheep play an important role in the Namibian livestock industry, there is a paucity of information on their production performance. The objective of the study was to compare the mature weights, and maturing rates for Damara, Dorper and Swakara sheep reared at Neudamm Farm. Four hundred and eight (408) sheep (84 Swakara, 296 Damara and 28 Dorper) were weighed monthly for 6 months. The Brody, Van Bertalanffy, Gompertz and logistic growth models were fitted to the data to determine the mature size and maturing rate. Based on the R2 and the BIC, the Brody growth function gave the best fit. The estimated mature weights for Damara, Dorper and Swakara sheep were 46.8±1.1 kg, 53.9±1.0 kg and 48.8±1.1 kg, respectively, with the corresponding maturing rates of 0.0037±0.0001, 0.0025±0.0003 and 0.0021±0.0001 kg/day. Although the Damara sheep have a smaller size compared to Dorper sheep, they mature faster, making them a better breed for mutton production. The Dorper had the largest mature sizes, although their rate of maturation was lower than the Damara sheep.
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creator: L Simasiku
creator: V Charamba
creator: E Lutaaya
rights: Copyright (c) 2019
date: 2019-12-29
publication date: 2019-12-29
starting page: 41
ending page: 48
doi: 10.32642/wijas.v1i0.1367

Evaluation of pre-emergence herbicides for weed control in maize
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description: Weed management is an ongoing constraint in southern Africa for conventional farming systems and in emerging conservation agriculture systems, which are more heavily reliant on herbicides for primary weed control. The challenge of rising labour costs and decreasing availability creates a greater need to develop effective and efficient weed management methods in key crops such as maize. Field experiments were conducted at Sebele Agricultural Research Station, Botswana in the 2011/12 and 2012/13 cropping seasons to evaluate pre-emergence application of atrazine at 1,000 and 2,000 g a.i. ha-1 and S-metolachlor at 1,440 and 2,880 g a.i. ha-1, and a tank mixture of atrazine at 1,000 and S-metolachlor at 1,440 g a.i. ha-1. Atrazine at either rate alone, effectively controlled annual broadleaf weeds: Acanthospermum hispidum, Datura ferox and Sesamum alatum, but failed to control annual grass weeds (Tragus berteronianus and Urochloa spp.). Conversely, sole application of S-metolachlor at either rate provided complete control of annual grass weeds, but poorly controlled annual broadleaf weeds except small-seeded Amaranthus hybridus and Amaranthus thunbergii. A tank mixture of atrazine and S-metolachlor provided broad-spectrum weed control and successfully controlled both annual broadleaf and grass weeds. Atrazine alone and in tank mixture with S-metolachlor significantly reduced annual broadleaf weed density and biomass and increased maize grain yield by more than 80% when compared with the weedy treatment. High weed density and biomass of annual broadleaf weeds in S-metolachlor treatments significantly reduced maize grain yield to levels similar to the weedy treatment. A pre-mixture of atrazine and S-metolachlor is recommended for broad-spectrum weed control. Using a combination of herbicides with different modes of action may reduce selection pressure for herbicide resistance.
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creator: Keotshephile Kashe
creator: Dikungwa Ketumile
creator: Paul Kristiansen
creator: Cornelius Mahilo
creator: Thebeetsile Moroke
rights: Copyright (c) 2020
date: 2020-12-05
publication date: 2020-12-05
starting page: 5
ending page: 18
doi: 10.32642/wijas.v2i.1437

Drivers of profitability in the Namibian cattle farming: A case study of north western Namibia
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description: The continuous changes in the economic, social and physical agricultural environment call for resilient livestock production systems and food chain networks around the world and Namibia in particular. Because of the low profitability, cattle farming in Namibia is heavily dependent on correct decision making for farmers to survive. Access to digital tools and interactive technologies for farming systems has increased rapidly and it is likely to play a significant role in meeting future challenges. This has not been properly propagated in beef cattle production areas of Namibia. The paper employed ordinary least square and dynamic models to investigate farmer’s net worth in livestock production systems as function of herd size per hectare, carcass price per kilogram and the El Niño Southern Oscillation Index. Results show that herd size per hectare significantly impacts net worth without prior knowledge about 1.627 percent, while exhibiting the impact of 1.523 percent on net worth with prior production knowledge. Farmers thus become more carcass price per kilogramme responsive (increases net worth by 1.131 percent) when prior information is incorporated in the decision making process at farm level. The price elasticity of the two models are 0.60 and 0.70, respectively, points out that improved access to knowledge allows for livestock price responsiveness of 0.1 percent. The significance of these variables calls for introducing technologies to mitigate the impact of changes on cattle production and the agribusiness sector by linking production to climate adaptability for resilient food markets.
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creator: Helmke Jens Sartorius von Bach
creator: Kennedy Muzamai Kalundu
rights: Copyright (c) 2020
date: 2020-12-05
publication date: 2020-12-05
starting page: 33
ending page: 44
doi: 10.32642/wijas.v2i.1417

Spatio-temporal variation in length-frequency and salinity tolerance of dominant fishes utilizing the Orange River-Estuary Continuum
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description: The length-frequency distribution of the dominant species of euryhaline marine Chelon richardsonii, estuarine Gilchristella aestuaria and freshwater species Labeobarbus aeneus, Mesobola brevianalis and Pseudocrenilabrus philander were investigated seasonally along the Orange River Estuary Continuum (OREC) during high-flow and low-flow periods, conducted in eight different years, within a 15-year period (2004-2018). Fish were sampled using a seine net at 18 sites spanning from the mouth of the estuary up to 35 km upstream. The length-frequency distributions of all species did not differ between the high-flow and low-flow season. Spatial differentiation in size frequency distribution of all freshwater taxon was recorded along the river-estuarine continuum but not for C. richardsonii and G. aestuaria. Total catch-per-unit-effort (catch per haul, CPUE) was low for both M. brevianalis and P. philander and their abundance declined downstream into the estuarine region as expected for these two freshwater species. A negative correlation between salinity and fish length of all five species was found, demonstrating that juvenile fishes, in particular, freshwater species are less salt-tolerant than the adults. It is concluded that the lower OREC provides an important fish nursery habitat suitable for growth and development, particularly for marine C. richardsonii and estuarine G. aestuaria.
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creator: Nashima FP
rights: Copyright (c) 2020
date: 2020-12-05
publication date: 2020-12-05
starting page: 19
ending page: 32
doi: 10.32642/wijas.v2i.1456

https://journals.unam.edu.na/index.php/WIJAS/article/view/1408
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title: The Bovine Major Histocompatibility Complex and Its Role in Tick and Tick-borne Disease Resistance and Immune Responsiveness in Bos Indicus and their Crosses with Bos Taurus in Sub-Saharan Africa: A Review
description: Ticks present a major challenge in livestock production given the increased demand for animal protein worldwide. Ticks cause worry, blood loss, damage hides and most importantly they are vectors of pathogens that cause severe diseases in livestock. Economic losses caused by ticks amounts to billions of dollars annually. The primary tick control method relies heavily on the use of acaricides. The increasing prices of these chemicals, environmental pollution, chemical residues in animal products and most importantly evolution of resistance of ticks to almost all available acaricides, has frustrated efforts of farmers to control ticks and tick-borne diseases. This has motivated researchers to search for alternative methods of tick control. The Major Histocompatibility complex (MHC) which is called Bovine Leuckocyte Antigen (BoLA) in cattle is an important component of the immune system which plays a major role in immune responses. The BoLA-DRB3 gene is the most polymorphic MHC class II gene locus where numerous associations have been found between the MHC polymorphism and disease resistance making it a good gene candidate for tick resistance. The Bos indicus breed is known to be more resistant to ticks and tick-borne diseases than the Bos Taurus. The use of tick and tick-borne disease resistant cattle breeds is a promising choice for tick and tick-borne disease control given the downsides of acaricides, vaccines and other tick control methods. This review summarizes available information on ticks and tick-borne diseases and the role of the Major Histocompatibility Complex in tick and tick-borne disease resistance.
subject: Articles
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creator: Theopoline Omagano Itenge
creator: Lavinia Haikukutu
creator: Japhet Robert Lyaku
rights: Copyright (c) 2020
date: 2020-12-07
publication date: 2020-12-07
starting page: 67
ending page: 80
doi: 10.32642/wijas.v2i.1408

A cross sectional comparison of chemical treatment on plant biodiversity at Neudamm farm, Namibia
type: item
description: This study determined the impact of Tebuthiuron application on plant biodiversity over a three-year period at Neudamm farm. A total of 40 (1m2) quadrats were randomly nested in three 250 m2 belt transects per each treatment to record the herbaceous plant density, species composition, dry matter and ground cover. Woody plant density, heights and canopy diameters were measured in each 250 m2 belt transects. A General Linear Model (GLM) procedure of SAS (2007) was used for analyses. The herbaceous biomass production was significantly higher (P < 0.05) in chemically treated site of 2015 (975 Kg DM ha-1) and least in the other two sites. The chemically treated site of 2016 had greater (P < 0.05) ground cover percentage than the other treatment sites. The canopy cover and woody plant densities in all woody height categories were higher (P < 0.05) in the control and chemically treated site of 2017, than the other two sites. The study concluded that the Tebuthiuron had impacted on the plant biodiversity of treated rangelands by improving the herbaceous plant species, biomass yields and reduced bush density. The study recommends that aftercare practices and application of arboricides be carried out routinely to allow herbaceous plants recovery. Keywords: Bush encroachment, arboricides, plant density, biomass production, canopy
subject: Articles
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subject: Array
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creator: Diina N. Shigwedha
creator: Absalom Kahumba
creator: Rosemary Shikangalah
rights: Copyright (c) 2020
date: 2020-12-07
publication date: 2020-12-07
starting page: 45
ending page: 57
doi: 10.32642/wijas.v2i.1402

A survey of the usage and storage practices of veterinary medicines among communal cattle farmers in the Kabbe South Constituency, Zambezi region.
type: item
description: Veterinary medicines are an indispensable tool for animal disease control and prevention. Misuse, improper handling and storage can render veterinary medicines less effective. A cross-sectional study was carried out on 60 cattle farmers in the Kabbe South Constituency of the Zambezi region in Namibia. The objective of the study was to find out the usage and storage practices of veterinary medicines. Selected farmers were interviewed using semi-structured questionnaires. Results of the study showed that the majority of respondents were males (78.3%, n=47) with at least primary school level education. Overall, farmers acquired and used 13 different types of veterinary medicines from licensed shops and pharmacies (73.4%, n=44), the state veterinary office (23.3%, n=14) and from unregistered veterinary medicine agents (3.3%, n=2). The medicines comprised of antibiotics (n=4); vaccines (n=3); combination of ectoparasiticide and anthelmintic (n=2), ectoparasiticide (n=1), anthelmintic (n=1) and vitamins (n=2). Although 36.7% (n=22) of the farmers owned or had access to a refrigerator, the majority (86.7%, n=52) did not maintain the cold chain. Most of the respondents (93.3%, n=56) self-diagnosed animal diseases and decided on the treatment without consulting a veterinarian. Oxytetracycline was the most commonly used veterinary medicine and was used at less than the recommended dose of 1ml/10kg by most respondents (83.3%, n=50). Although farmers sourced veterinary medicines from licensed retailers, the break in the cold chain and the under dosing of medicines may impair effectiveness. Self-diagnosis and treatment of animal diseases promotes misuse and the development of antibiotic resistant bacteria in cattle which may render antibiotics on the market less effective. The training of all stakeholders along the veterinary medicine value chain in the region is recommended.
subject: Articles
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creator: Oscar Madzingira
creator: Sikabongo Simasiku
rights: Copyright (c) 2020
date: 2020-12-07
publication date: 2020-12-07
starting page: 58
ending page: 66
doi: 10.32642/wijas.v2i.1411

Polymorphism of the KAP1.3 and KRT33A genes in the Swakara sheep of Namibia
type: item
description: The objective of the study was to determine polymorphism in the KAP1.3 and KRT33A genes of Swakara sheep. Blood samples were collected from 40 Swakara sheep randomly selected from four farms; Neudamm, Gellap-Ost, Kalahari and Tsumis. Genomic Deoxyribonucleic acid was isolated using the Inqaba biotech-kit protocol. PCR-Single strand conformational polymorphism gel electrophoresis method was used to genotype the two genes. The PCR products were sequenced to construct phylogenetic trees for evolutionary analyses. Chi-square test at 5% level of significance was used to analyze the data. Three genotypes were identified at KAP1.3 gene, with genotype frequencies of 0.5 (AA), 0.35 (AB) and 0.15 (CC). The frequency distribution of genotypes across all four farms differ significantly (P=0.05). Two genotypes (AA and BB) of the KRT33A gene were identified. The KRT33A locus was not statistically significant (P=0.118), and the allele frequency was 0.25 (A) and 0.75 (B). The KAP1.3 and KRT33A genes showed no significant deviation from the Hardy Weinberg Equilibrium. Phylogenetic tree showed relatedness of the Swakara sheep found in Namibia. The revealed polymorphism in the KAP1.3 and KRT33A may prompt further studies on KAP genes in Swakara sheep, which may help with the identification of genetic markers linked to superior pelts and strategic selection of breeding stock.
subject: Articles
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subject: Array
  topic: keywords
creator: Nellia Felicity Nyoni
creator: Theopoline Omagano Itenge
creator: Maria N. T. Shipandeni
rights: Copyright (c) 2020
date: 2020-12-07
publication date: 2020-12-07
starting page: 81
ending page: 93
doi: 10.32642/wijas.v2i.1406

Effect of legume hay supplementation on feed intake, growth, digestibility and volatile fatty acid production of Xhosa goats
type: item
description: Abstract The objective of this study was to evaluate the effects of sex and supplementing Chloris gayana hay with either Lablab purpureus or Vigna unguiculata on growth, volatile fatty acid (VFA) production and apparent nutrient digestibility. Eighteen goats, one-year-old, of average live weight 14.13 ±0.24kg was apportioned in a completely randomized design to three diets which were iso-nitrogenous and iso-energetic. Animals were housed individually with 6 animals per treatment composed of three males and three females. Total DM intake was higher (P < 0.05) in T2 (694.8 g/head/day) and T3 (688.1 g/head/day) compared to T1 (607.8 g/head day). The goats gained at a rate of 35.0g/d; 45.0g/d and 38.3g/d for T1, T2, and T3, respectively. Goats on T2 showed a non-significantly higher (P > 0.05) growth rate exhibiting total gain of 2.68kg compared to 2.08kg and 2.33kg for T1 and T3, respectively. Animals on T1 (19.16) exhibited a significantly lower FCR (P < 0.05) than T2 (15.44) and T3 (18.11). Apparent DM digestibility were significantly different (P < 0.05) among treatment diets. Sex significantly influenced DM, ADF and NDF digestibilities (P < 0.05). There were no significant (P > 0.05) differences in individual VFA molar concentrations among treatment diets and due to sex for acetate, propionate, valerate, iso-butyrate and iso-valerate. However, diets significantly influenced butyrate concentration (P < 0.05) with 0.25, 0.95 and 0.25mM for T1, T2 and T3, respectively. The percentage molar concentration for acetate was 75%, 73%, and 77% while the propionate concentration was 12%, 8% and 10.7 % for T1, T2, and T3, respectively. The acetate to propionate ratio was 6.2, 9.12 and 7.15 for T1, T2, and T3, respectively. In conclusion, the study demonstrated that Cowpea and Lablab forages can support growth in goats at the same level of CP as in commercial pellets.
subject: Articles
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subject: Array
  topic: keywords
creator: John Mupangwa
creator: Soul Washaya
creator: Voster Muchenje
rights: Copyright (c) 2021 John Mupangwa, Soul Washaya https://creativecommons.org/licenses/by-nc-nd/4.0
date: 2022-09-13
publication date: 2022-09-13
starting page: 37
ending page: 49
doi: 10.32642/wijas.v3i.1459

Agronomic and morphological diversity of Bambara groundnut (Vigna subterranea (L.) Verdc.) accessions in North-Central Namibia
type: item
description: Bambara groundnut (Vigna subterranea (L) Verdc.) is an orphan, underutilised and less exploited crop in Africa and beyond, yet it is an essential traditional crop for subsistence farmers in sub-Saharan Africa. Currently, in Namibia, neither a pre-breeding nor a breeding programme exists for Bambara groundnut. Twenty-five Bambara groundnut accessions acquired locally and outside Namibia were characterised for descriptor state, including possible character diversity on the quantitative descriptors. Square lattice design with three replications was used. Data were analysed using analysis of variance (ANOVA), Pearson correlation moment, Principal Component Analysis (PCA), and cluster analysis. ANOVA indicated significant differences (P < 0.05) among accessions for most of the characters measured, and highly significant differences (P < 0.01) for the number of pods per plant, pod yield, seed yield, plant height, and dry biomass. The dendrogram sub-criterion indicated three clusters, confirming the results of the PCA, which grouped accessions with common descriptors in the same quadrants. PCA biplot showed that the first two components explained 59.55% of the variation. Overall results suggest that the Bambara groundnut accessions evaluated in this study showed high variability, thus can be used as a source of pre-breeding materials to initiate a national breeding programme.
subject: Articles
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subject: Array
  topic: keywords
subject: Array
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subject: Array
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subject: Array
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subject: Array
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creator: J S Valombola
creator: L M Akundabweni
creator: S K Awala
creator: K Hove
rights: Copyright (c) 2019
date: 2019-12-29
publication date: 2019-12-29
starting page: 88
ending page: 99
doi: 10.32642/wijas.v1i0.1369

The effect of arboricide application on soil chemical properties at Neudamm farm, Namibia
type: item
description: Abstract This study assessed the effects of chemical treatments on soil chemical properties at Neudamm farm. A total of 6 composite soil samples were randomly collected from all three 250 m2 belt transects in each of the three chemically treated and control sites at a depth of 15 cm using a soil auger. The soil was analysed for pH, organic matter, organic carbon and soil minerals. A GLM procedure of SAS was used for analyses. The soil pH was significantly (P < 0.05) higher in the chemically treated site of 2015 (6.06), followed by the control (5.61) and the chemically treated site of 2017 (5.5). The OC and OM percentages were greater (P < 0.05) in the chemically treated site of 2015 than in all three sites. The chemically treated site of 2016 had the highest soil Ca (551 ppm), K (197.3 ppm), Mg (76 ppm), P (23.3) contents, followed by the site of 2015, than the control site. The study concluded that chemically treated sites had improved soil fertility through controlled bush density. The study recommends that arboricides should be applied as aftercare and for long term monitoring be carried out routinely to acquire systematic trends of the soil chemical properties.
subject: Articles
  topic: section
subject: Array
  topic: keywords
creator: Absalom Kahumba
creator: Diina N. Shigwedha
creator: Rosemary N. Shikangalah
rights: Copyright (c) 2022 Absalom Kahumba, Diina N. Shigwedha, Rosemary N. Shikangalah https://creativecommons.org/licenses/by-nc-nd/4.0
date: 2022-09-09
publication date: 2022-09-09
starting page: 1
ending page: 10