Browsing by Author "Nyoni, Nellia Felicity"

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    A 13-year retrospective study of the beef and dairy cattle losses at Neudamm farm in the Khomas region of Namibia
    (2017) Kandiwa, Erick; Madzingira, Oscar; Mushonga, Borden; Samkange, Alaster; Bishi, Alec S.; Nyoni, Nellia Felicity
    This study was carried out to get an appraisal of the losses occasioned by apparently high levels of stock mortality at Neudamm farm, University of Namibia. Losses of beef cattle (Afrikaner, Simmental and Sanga/Nguni) and dairy cattle (Friesian) were studied from July 2003 to December 2015. A total of 106 animals worth US$55 263.12 and representing 3.5% (SD=0.8%) of the animals at risk were lost during this period. In the years 2004, 2006, 2007, 2010, 2012, 2013 and 2014 the cattle losses were more than 1.5% whereas in 2005, 2008, 2011 and 2015 the losses were 1.0-1.5%. The lowest losses (<1.0%) occurred in 2003 and 2009. Since 2005, overall cattle losses rapidly increased until 2010 followed by a gradual decrease till 2015. Though there was no significant difference in the overall losses between male {3.4% (SD=0.7%)} and female animals {3.8% (SD=0.9%)} during the study period (P>0.05), the female losses were significantly higher than the male losses (P<0.05) in all the years except 2011 during which there was no significant difference between male and female losses (P>0.05). There were significantly more mature animals lost from 2003 to 2009 and from 2013 to 2014 (P<0.05). There was no significant difference in the mature and immature losses in 2012 (P>0.05). The losses in immature cattle were higher than those of mature cattle in 2010, 2011 and 2015 (P<0.05). The proportions of animals lost due to predation, unknown causes, dystocia, infections, trauma, old age, plant intoxication and traumatic reticulo-peritonitis were 29.2%, 29.2%, 14.2%, 11.3%, 9.4%, 4.7%, 0.9% and 0.9%, respectively. For the duration under study, the proportional losses in January, February, April, November and December were significantly higher than those of the rest of the months (P<0.05). Neudamm farm lost 3.5% of their beef and dairy stock, worth US$55 263.12, over a 13 year period as a result of infectious and non-infectious causes. The dynamics of the losses were such that the losses were higher in some years than others, more young than older animals were lost and, though not statistically significant, more females were lost than males.
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    Identification of genetic variation in the Keratin-associated protein and KRT33A genes of the Swakara sheep of Namibia
    (University of Namibia, 2020) Nyoni, Nellia Felicity
    Keratins are structural intermediate filamentous proteins that constitute about 90% of the total wool fiber in sheep. The protein gene family is divided into two groups which are the Keratin Intermediate-Filament proteins (KRTs) and the Keratin-Associated proteins (KAPs). The KRTs form the skeletal structure of the wool fiber (micro-fibrils) and are embedded in a matrix of KAPs through disulphide cross-linkages. Genetic variation in the keratin genes may be associated with pelt quality traits. Pelt quality is determined by the unique hair formation, which is determined by these protein genes. High demand of exceptional pelts by the fashion industry, has probed this study in determining genetic variation in Keratin genes (KAP1.1, KAP1.3, KAP3.2) and KRT33A). The study also examined allele frequency distribution of the keratin genes in Swakara sheep in Namibia. Blood samples were collected from 168 Swakara sheep randomly selected from four farms; Neudamm, Gellap-Ost, Kalahari and Tsumis. Genomic Deoxyribonucleic acid (DNA) was isolated using the Inqaba biotech-kit protocol. Extracted genomic DNA was confirmed using a Nano drop and amplified using the Polymerase Chain Reaction (PCR). Genetic variation was assessed using PCR-Agarose gel electrophoresis in the KAP1.1 gene. As for the KAP1.3, KAP3.2 and KRT33A, genetic variation was assessed using Polymerase Chain Reaction-Single Strand Conformational Polymorphism (PCR-SSCP). Sequenced keratin genes under investigation and those retrieved from NCBI were grouped together and used to construct phylogenetic trees on Molecular Evolutionary Genetics Analysis (MEGA) version 6.0. At the KAP1.1 locus, the study revealed three alleles; A, B and C with genotype frequencies of 0.13, 0.57 and 0.30, respectively. Mostly the B allele frequency was highly distributed in comparison to the A and C alleles. At the KAP1.1 locus, the study reports statistical significant difference in allele frequency distribution amongst the four farms (P=0.004). The KAP3.2 locus had one allele identified across all four farms and denoted as A. The KAP1.3 locus was statistically significant at P=0.160 with genotype frequencies of 0.5 (AA), 0.35 (AB) and 0.15 (CC). The KRT33A locus was not statistically significant (P=0.402), and had 0.25 (A) and 0.75 (B) allele frequency. The four genes under study showed no significant deviation from Hardy Weinberg Equilibrium. The findings of this study which reports genetic variation in the KAP1.1, KAP1.3 and KRT33A has the potential to help with the identification of genetic markers linked to superior pelts. The use of genetic markers in the selection of Swakara sheep breeding program would potentially increase the accuracy of selection, and compliment visual appraisal technique that is currently being used in the Swakara sheep industry.