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"Kandiwa, Erick"
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Production performance of sheep and goat breeds at a farm in a semi-arid region of Namibia
by
Bishi Alec Simukai
,
Madzingira Oscar
,
Kandiwa Erick
in
Arid regions
,
Arid zones
,
Birth weight
2020
This study retrospectively investigated the effect of breed and season on the lambing/kidding dynamics, growth performance, neonatal viability, and weaning dynamics of sheep (Damara, Dorper, and Swakara) and goats (Boer goat and Kalahari Red) at a farm in the Khomas Region of Namibia between 2004 and 2015. Litter size was dependent on breed (X2(12, N = 3388) = 796, p < 0.001), with twinning more frequent in Dorper sheep and Kalahari Red and Boer goats than in the Damara and Swakara sheep (p < 0.05), while triplets were more prevalent in the Dorper sheep and Kalahari Red goats (2.8% and 1.0%, respectively; p < 0.05). Distribution of birth weight categories was dependent on breed. There was a significant difference in the proportions of birth weight categories between breeds (X2(12, N = 3388) = 467, p < 0.001) whereby Dorper lambs were mostly born weighing below 3 kg (2.6%, p < 0.05); Boer goat kids, Kalahari Red kids, and Damara lambs were mostly born weighing 3 to < 4 kg (4.3%, 6.3% and 19.9%, respectively; p < 0.05); Swakara lambs were mostly born weighing 4 to < 5 kg (12.2%, p < 0.05), and Swakara lambs were mostly born weighing ≥ 5 kg (3.3% and 2.3%, respectively, p < 0.05). Weaning age categories were dependent on breed (X2(12, N = 3388) = 241, p < 0.001) whereby Dorper lambs were mostly weaned at below 3 months of age (2.8%, p < 0.05); Damara lambs were mostly weaned at 3 to < 5 months of age (12%, p < 0.05), and Boer goat kids were mostly weaned at ≥ 5 months of age (0.9%, p < 0.05). Neonatal viability was dependent on breed (X2(8, N = 3388) = 49.2, p < 0.001) whereby Dorper lambs were more susceptible to abortions and neonatal deaths (0.6% and 1.5%, respectively; p < 0.05) than the rest of the breeds. Breed and lambing season interacted to produce effects on the birth weight of offspring although lambing season alone did not have a significant effect on Boer goat and Kalahari Red kids’ birth weights.
Journal Article
Applicability of teeth examination as a tool for age estimation in a semi-arid cattle production environment in Namibia
2020
Regression analysis was used to evaluate teeth examination as a tool for estimating age in beef and dairy cattle at Neudamm farm, Namibia, in 2018. There was a significant difference in age (months) between the overall mean actual age (M=60, SD=4.57) and the mean estimated age (M=57, SD=4.52 months) in beef cattle; t(74) = 3.61, p<0.001. There was no significant difference between the overall mean estimated age and the mean actual age (M=42.5, SD=5.18) and (M=41.3, SD=5.21 months) in dairy cattle; t(30) = 1.45, p=0.16. There was a very strong positive relationship between the overall teeth examination-estimated age and actual age in beef cattle [r (74) = 0.98, p<0.001]. There was a very strong positive relationship between the overall teeth examination-estimated age and actual age in dairy cattle [r (30) = 0.99, p<0.001]. A very strong positive relationship was also evident between the teeth examination-estimated age and actual age in beef cattle aged 45 months and below [r (37) = 0.93, p<0.001]. There was a very strong positive relationship between the teeth examination-estimated and actual age in dairy cattle aged 45 months and below [r (20) = 0.97, p<0.001]. There was a very strong positive relationship between the teeth examination-estimated age and actual age in beef cattle aged over 45 months [r (35) = 0.93, p<0.001]. There was a very strong positive relationship between the teeth examination-estimated age and actual age in dairy cattle aged over 45 months [r (8) = 0.97, p<0.001]. It was therefore concluded that under the given conditions of the study and the range of ages and the breeds under study, age estimation through teeth examination is reliably applicable for aging cattle in general. Age estimation through teeth examination was found to be more accurate in dairy than in beef cattle.
Journal Article
Quantitative Characterization of the Hemorrhagic, Necrotic, Coagulation-Altering Properties and Edema-Forming Effects of Zebra Snake (Naja nigricincta nigricincta) Venom
by
Fabiano, Ezequiel
,
Kandiwa, Erick
,
Mushonga, Borden
in
Analysis
,
Animal behavior
,
Anticoagulants
2018
This study was designed to investigate the cytotoxicity and haemotoxicity of the Western barred (zebra) spitting cobra (Naja nigricincta nigricincta) venom to help explain atypical and inconsistent reports on syndromes by Namibian physicians treating victims of human ophidian accidents. Freeze-dried venom milked from adult zebra snakes was dissolved in phosphate buffered saline (PBS) for use in this study. Haemorrhagic and necrotic activity of venom were studied in New Zealand albino rabbits. Oedema-forming activity was investigated in 10-day-old Cobb500 broiler chicks. Procoagulant and thrombolytic activity was investigated in adult Kalahari red goat blood in vitro. The rabbit skin minimum hemorrhagic dose (MHD) for N. n. nigricincta was 9.8μg. The minimum necrotizing dose (MND) for N. n. nigricincta venom was 12.2μg. The N. n. nigricincta venom showed linear dose-dependent procoagulant activity on goat blood (p<0.05). Likewise, N. n. nigricincta venom showed linear dose-dependent thrombolytic activity on goat blood (p<0.05, n = 6). Subplantar injection of N. n. nigricincta venom (25μg, 50μg, 75μg, and 100μg) into chick paw resulted in peak oedema of 35.5%, 38.5%, 42.9%, and 47.5%, respectively, two hours after injection. Paw oedema subsided within five hours to a mean volume ranging from 5% (25μg venom) to 17.6% (100μg venom). In conclusion, though N. n. nigricincta belongs to the genus Elapidae, the current study has shown its venom to possess potent hemorrhagic, necrotic (cytotoxic), and paradoxically, both procoagulant and thrombolytic activity. The authors propose further work to fractionate, isolate, and elucidate the structure of the various N. n. nigricincta venom toxins as a prelude to the development of an antivenom.
Journal Article
A retrospective sero-epidemiological survey of bovine brucellosis on commercial and communal farming systems in Namibia from 2004 to 2018
by
Henriette, van Heerden
,
Madzingira Oscar
,
Fasina Folorunso Oludayo
in
Beef
,
Brucellosis
,
Cattle
2020
Cattle production is the major livestock production activity and the mainstay of Namibia’s economy. Sustained beef exports are contingent on a sound sanitary environment where diseases such as brucellosis are under control. In this retrospective study, 49,718 bovine brucellosis testing results from 2004 to 2018 were analyzed to determine the proportion of sero-positive cattle and herds, and the spatial distribution of positive reactors from commercial and communal areas. In total, 244 positive reactors were identified based on the Rose Bengal Test (RBT) and the Complement Fixation Test (CFT) in series, giving an overall proportion of infected animals of 0.49% (244/49,718; 95% CI, 0.43–0.56%) and an overall proportion of infected herds of 9.26% (78/842; 95% CI, 7.49–11.41%). There was a higher proportion of sero-positive communal herds (33.09%) and cattle (10.27%) than commercial herds (4.67%) and cattle (0.24%; p < 0.05). Annually, the proportion of positive reactors was 0–1.37% in the commercial area and 0–52.38% in the communal areas, with a clear decline in positive reactors in the communal areas. Within the commercial sector, the proportion of positive reactor dairy, beef, and export cattle was 0.19% (51/27,067; 95% CI, 0.14–0.25%), 0.30% (48/16,098; 95% CI, 0.22–0.40%), and 0.33% (16/4811; 95% CI, 0.20–0.54%), respectively. Abortions were found to be the major reason for Brucella testing in the communal areas. About 12.65% (96/759) of abortion-linked sera tested positive in the communal areas, but none were positive in beef or dairy cattle. Widespread vaccination of cattle and robust planned surveillance is recommended to reduce the incidence of the disease, its associated production losses and public health risk.
Journal Article
Nutritional assessment of three baled rice straw varieties intended for use as ruminant feed in Namibia
by
Mwenda, Evelyn Nanjeke
,
Hepute, Venaune
,
Mupangwa, John F.
in
acid detergent fiber
,
acid insoluble lignin
,
agriculture
2021
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.
Journal Article
Seroprevalence of African horse sickness in selected donkey populations in Namibia
by
Kandiwa, Erick
,
Molini, Umberto
,
Mushonga, Borden
in
african horse sickness
,
donkeys
,
enzyme-linked immunosorbent assay
2020
Background and Aim: African horse sickness (AHS) is a non-contagious viral disease of horses and other equids caused by an arbovirus belonging to the Reoviridae family and genus Orbivirus. AHS is an endemic disease that is responsible for the death of a high number of horses every year in Namibia. At present, there is no information on the prevalence and distribution of AHS virus (AHSV) serotypes in the different regions of Namibia. Therefore, this survey aimed to fill this knowledge gap by investigating the AHSV seroprevalence in Namibian donkeys. Materials and Methods: A total of 260 blood samples (20 samples for each region) were randomly collected from donkeys aged between 3 and 5 years. Sera were screened for AHSV-specific immunoglobulin G antibodies using a commercial competitive enzyme-linked immunosorbent assay kit and samples positive to AHSV antibodies were further tested by serum neutralization (SN) assay to evaluate the AHSV serotype-specific immune response. Results: Seroprevalence of antibodies against AHSV in Namibian donkeys was 63.5%. The AHSV prevalence was significantly higher in the northern region (64%) than in the southern region (36%). A significantly (p<0.05) higher number of donkeys had antibodies against AHSV-6 (37.8%) and AHSV-9 (37.8%). The AHSV-2, AHSV-6, and AHSV-9 prevalence were higher (p<0.05) in the northern regions compared to the southern regions. None of the donkeys in this study, however, tested positive for AHSV-8. Conclusion: Results of the current study indicate that all AHSV serotypes have either circulated previously or are circulating in Namibia except for AHSV-8. In particular, AHSV-1, -2, -3, -4, -5, -6, and -9 serotypes have circulated or are circulating in the northern region of Namibia, while AHSV-1, -4, -5, -6, -7, and -9 have infected donkeys in the south. AHSV-9 and AHSV-6 were the most prevalent serotypes detected in donkeys in this study. SN results showed that several donkeys from Kavango East, Kavango West, and Ohangwena regions had been exposed to multiple serotypes, indicating the possibility of cocirculation of several strains in Namibia.
Journal Article
A 3-year prospective study of the incidence of gastric ulcers in pigs slaughtered at Base Abattoir in Rwanda
by
Kandiwa, Erick
,
Habarugira, Gervais
,
Mushonga, Borden
in
Abattoirs
,
Antiulcer agents
,
Base Abattoir
2017
Determination of the incidence of gastric ulcers in pigs slaughtered at Base Abattoir in Rwanda.
Stomachs from all 5040 pigs that were slaughtered at Base Abattoir in Rwanda from August 2012 to August 2015 were examined for the presence and location of gastric ulcers. The results of the inspections were recorded and analyzed. Statistical analysis for Chi-square values was performed using the Software Package for Social Sciences version 16.0. The Z test for comparison of proportions was used and p<0.05 was considered significant.
Overall as well as per district, significantly more male pigs than female pigs were slaughtered (p<0.05). The incidence of gastric ulcers in slaughter pigs was 12.86%. The incidence of gastric ulcers in males (13.36%) was not significantly different (p>0.05) from that in female pigs (12.84%) in all three districts. A significantly greater proportion of these ulcers (69.03%) was located in the esophageal region than in the glandular region of the stomach (30.97%) in slaughtered males (p<0.05). A significantly greater proportion of these ulcers (79.59%) was located in the esophageal region than in the glandular region of the stomach (20.41%) in slaughtered females (p<0.05). The overall incidence of esophageal ulcers (9.44%) in the slaughtered pigs was significantly (p<0.05) higher than that of glandular region ulcers (3.41%). Pigs with carcass weight over 60 kg showed a significantly (p<0.05) higher (44.44%) incidence of ulcers than those between 40 and 60 kg (33.33%) and those below 40 kg (22.22%).
It was concluded that the incidence of gastric ulceration in slaughter pigs at Base Abattoir was not associated with source (district) or sex of pigs but was associated with the carcass weight.
Journal Article
African Swine Fever Outbreak at a Farm in Central Namibia
by
Jago, Mark
,
Kandiwa, Erick
,
Molini, Umberto
in
African swine fever
,
Case Report
,
Case reports
2019
An outbreak of African swine fever (ASF) occurred at a farm in central Namibia in March 2018. Fourteen pigs died out of a herd of 59 animals over a period of 16 days between the first and sixteenth of March 2018. The clinical signs observed included sternal recumbency, fever, weakness, pain and reluctance to move, hyperemia of the skin and anorexia, followed by death. Necropsy findings included large amounts of unclotted blood in the pleural and peritoneal cavities, diffuse carcass congestion, splenomegaly, consolidation of both lungs, hemorrhagic and frothy airways and trachea, hepatomegaly and congestion, congestion of the gastric mucosa, enlarged and congested kidneys, ecchymotic epicardial, and endocardial hemorrhages, and very enlarged and congested urinary bladder. All the remaining pigs were euthanized, burned, and buried under state veterinary supervision. The authors concluded that the outbreak resulted from indirect transmission of the ASF virus due to lapses in biosecurity measures.
Journal Article
Prevalence and risk factors for brucellosis seropositivity in cattle in Nyagatare District, Eastern Province, Rwanda
2018
A survey involving 120 small-scale dairy farmers was carried out to assess risk factors associated with brucellosis in cattle from selected sectors of Nyagatare District, Rwanda. A sample of cattle from nine selected sectors of Nyagatare was tested for brucellosis using the Rose Bengal Test. Of the respondents, 57.5% were unaware of brucellosis as a disease, 85.8% did not screen new additions to the herd for brucellosis and 82.5% did not remove brucellosis seropositive animals from the herd. The prevalence of brucellosis in herds with cows with no history of abortion was 38.5% and 17.0% in those with a history of abortion. None of the respondents disinfected abortion sites or vaccinated against brucellosis. The prevalence of brucellosis in cows with a history of retained placenta was 36% and 2% in those with no history of retained placenta. Of the respondents, 62.5% reportedly fed foetal membranes to dogs. About 65.8% of the respondents with brucellosis-positive animals reported a calving interval longer than 1 year. Katabagemu (28.6%) had the highest prevalence of brucellosis seropositivity while Karama had none. Brucellosis in cows (21.4%) was significantly higher than that in heifers (12.8%) (p 0.05). The occurrence of brucellosis in herds with 40–70 cattle (26.9%) was significantly greater than the 14.9% of herds with 10–39 cattle (p 0.05). Seropositivity to brucellosis was significantly different (p < 0.05) between the fourth parity (32.5%) and first parity (14.3%) cows. The findings in this study confirmed the existence of brucellosis as a problem in Nyagatare and the authors recommend that farmer education on the epidemiology, risk factors and mitigation of the disease be undertaken as a matter of urgency.
Journal Article
Conception rates and calving intervals of different beef breeds at a farm in the semi-arid region of Namibia
2019
A retrospective study from 2004 to 2017 investigated the effect of bull age, cow age and breed on conception rates, and calving intervals of beef cattle at Neudamm farm, Khomas region, Namibia. Bulls ranging from 4 to 14 years of age were used to breed cows up to 17 years of age. A total of 1804 pregnancies were diagnosed in Afrikaner (81.8%), Nguni (14.1%), and Simmental (4.1%) cows. The overall conception rate of beef cattle during the study period was 71.7 ± 9.5%. The overall conception rate of the Nguni cows (78.3%) was significantly higher than that of the Afrikaner (70.9%) and the Simmental cows (64.9%) (p < 0.05). The age of sires had no effect on overall conception rate in all three breeds (p > 0.05). Afrikaner dams more than 10 years old had the least rate of conception (60.4%, p < 0.05) within that breed category. Nguni dams between four to 10 years had the greatest conception rate (86.5%, p < 0.05). Age of dams had no effect on conception rates in Simmental cattle (p > 0.05). The overall mean length of all calving intervals in the Nguni cows (366 ± 35 days) was significantly shorter than those of the Afrikaner cows (487 ± 62 days) and the Simmental cows (484 ± 110 days) (p < 0.05). The 2013 breeding season produced the highest overall conception rates (~ 85%), and the 2007 breeding season produced the lowest overall conception rate (~ 51%). From a fertility point of view, the Nguni breed seemed best suited for the semi-arid conditions which are prevalent in most of Namibia.
Journal Article