105 research outputs found
Genetic diversity and population structure of locally adapted South African chicken lines: Implications for conservation.
In this study microsatellite markers were applied to investigate the genetic diversity and population structure of the six local chicken lines kept in the “Fowls for Africa” program, for better clarification of parameters for breed differentiation and genetic conservation of this valuable resource. The lines included the Black Australorp, Potchefstroom Koekoek, New Hampshire, Ovambo, Lebova- Venda and a Naked Neck line. Unbiased estimates for heterozygosity ranged from 50% in the Potchefstroom Koekoek to as high as 65% in the Naked Neck chickens. FIS values varied from as low as 0.16 for the Black Australorp line to as high as 0.35 for the Ovambo chickens. The FST values indicated moderate to high genetic differentiation between the Naked Neck and New Hampshire (0.11); Ovambo and Naked Neck lines (0.12), and Naked Neck and Lebowa- Venda (0.14). A total of 13% of the total genetic variation observed was between the chicken lines and 87% within the lines, supporting moderate genetic differentiation. Population structure was assessed using STRUCTURE where the Black Australorp was genetically best defined. Although six clusters for the different populations could be distinguished, the other lines were not as clearly defined, with individual birds tending to share more than one cluster. Results support a broad classification of these lines and further investigation of unique alleles is recommended for conservation of the lines within the program
Carcass characteristics of South African native chicken lines
Carcass characteristics of the Koekoek, New Hampshire, Naked-Neck, Lebowa-Venda and Ovambo chicken lines were evaluated. The highest dressed-carcass mass was recorded for Ovambo chickens and the highest percentage breast muscle was recorded for Naked-Neck chickens. Percentage fat and fatty acid composition differed between lines (p < 0.05). Carcass mass and fat content of the native chicken lines were less than in a commercial broiler line. It was concluded that the Ovambo and New Hampshire chicken lines appear to have the most suitable carcass characteristics for low-input systems where poultry production is aimed at household food security.
(South African Journal of Animal Science: 2000, 30(1): 53-56
Genetic characterization of native southern African chicken populations: evaluation and selection of polymorphic microsatellite markers
This study presents the first results on the evaluation and selection of polymorphic microsatellite markers for the genetic characterization of native chicken populations in southern Africa. Blood samples for DNA extraction were obtained from five chicken lines from South Africa (Koekoek, New Hampshire, Naked-Neck, Lebowa-Venda and Ovambo), and from one population each from Mozambique and Botswana. Twenty-three markers were found to be polymorphic in most of the lines studied. The mean number of alleles observed for all markers was 6.1, and varied from 2.3 (Koekoek) to 4.3 (Mozambique population). The lowest heterozygosity was found in the Koekoek line (31.4%), and the highest in the populations from Mozambique (60.7%) and Botswana (61.2%). It was concluded that this particular set of microsatellite markers can be of use a measure of genetic variability in native chicken lines in southern Africa, and should be evaluated as diagnostic tools for breed identification.
(South African Journal of Animal Science, 2000, 30(1): 1-6
Comparison of on-farm progeny performances from local and imported boar semen used in the South African pig industry
The widespread use of artificial insemination in the pig industry has provided breeders with access to genetic material from superior boars from around the world. Selection of parent stock is based on estimated breeding values (EBVs), which are regularly computed in all countries performing genetic evaluations. The purpose of this study was to evaluate the value of foreign sires in the South African (SA) pig industry by comparing the on-farm performances of progeny for average daily gain (ADG), feed conversion ratio (FCR) and back fat thickness (BF) from progeny sired by USA and Canadian born sires to the performance of progeny from local sires and to progeny with paternal USA grandsires (F1-US sires). The breeds analysed comprised of Duroc, Landrace and Large White pigs. Males outperformed females for all traits measured (P <0.0001). Large differences (P <0.0001) were observed between on-farm performances which had similar climatic regions for all traits except Duroc BF (P <0.05). Farm differences were consequently attributed to management rather than environmental influences. The effect of country was significant (P <0.05) in all the models tested with the USA-sired progeny having the best overall performance. However, as measured by a stepwise R2, country remained the smallest contributor to variation across all models (except BF in Landrace), with farm, sex and year-season contributing larger portions to the variation observed in the on-farm performances of progeny. These results indicate that most of the variation observed could be attributed to differences in farm as explained by management, rather than superiority of the imported boar semen.Keywords: Average daily gain, back fat thickness, feed conversion ratio, on-farm performanc
Genetic and phenotypic characterization of native fowl populations in South Africa
Native fowl populations in South Africa were characterized genetically and phenotypically. Four South African native populations, two dual-purpose breeds, and two populations from Mozambique and Botswana were included for genetic analysis. For phenotypic characterization, two commercial lines were also included as a benchmark. Twenty-three micro satellite markers were selected and tested to obtain genetic data for estimation of genetic variability and distance. Growth (weight gain) and egg production were included for phenotypic characterization. A relatively high (53% ¬64%) genetic variation was found among the populations, which suggests conservation as a genetic resource for future use. The lowest genetic variation (53%) was found for the Koekoek and Australorp populations, which are the two populations that were subjected to formal selection, while the highest variation was observed in the Naked Neck population (64%). The New Hampshire has often been included in upgrading programs and this is evident from the close relationship with both the Lebowa- Venda and Naked Neck fowls. Phenotypic trials indicated significant differences among the populations included for growth, carcass and egg production traits. The Koekoek and New Hampshire populations had the best performance for egg production and growth (weight gain) in the study. Genetic and phenotypic differences indicate that the populations can be distinguished as different breeds or groups of fowl. The results of this study may contribute to selection for improved performance for household food production, as well as conservation of the populations as a genetic resource.Thesis (PhD)--University of Pretoria, 2001.Animal and Wildlife Sciencesunrestricte
Strategies for the genetic improvement of South African Angora goats
Selection of Angora goats over the past decades has focused on traits related to fitness, body
weight and fiber production. Research for genetic improvement of the Angora has been based on
quantitative selection and more recently molecular technology has been applied. Although
considerable progress has been made at increasing fine mohair production, the inability of Angora
goats to survive sub-optimum conditions has become a concern. Selection emphasis on fibre
production resulted in unthrifty animals and the South African (SA) Angora industry is still hampered
by the loss of young goats. DNA marker information assists conventional selection by increasing
selection accuracy, improving the rate of genetic improvement and leading to a better understanding
of the physiological background of traits. The genetic diversity of the SA Angora goat breed was
estimated and an improved linkage map was recently developed. The extensive production systems in
South Africa pose a challenge for pedigree integrity, and a microsatellite panel was constructed for
parentage verification. Selection for quantitative trait loci (QTL) will lead to increased genetic
progress and offers the opportunity to improve understanding of and exploit phenotypic variation.
Putative QTL associated with fleece and growth traits have been identified in the South African
Angora goat population. The current goat SNP chip does not include any fibre-producing goat breed,
and this chip is currently being verified in the SA Angora goat population, in conjunction with the
sequencing of certain keratin genes.http://www.elsevier.com/locate/smallrumreshb201
Pharmacy fall prevention services for the community-dwelling elderly:Patient engagement and expectations
Medication use is an important risk factor for falls. Community pharmacists should therefore organise fall prevention care; however, little is known about patients' expectations of such services. This qualitative study aims to explore the expectations of community-dwelling older patients regarding fall prevention services provided by community pharmacies. Telephone intakes, followed by three focus groups, were conducted with 17 patients, who were aged ≥75 years, used at least one fall risk-increasing drug (FRID) and were registered at a community pharmacy in Amsterdam, the Netherlands. Some time of the focus groups was spent on playing a game involving knowledge questions and activities to stimulate discussion of topics related to falling. Data were collected between January 2020 and April 2020, and all focus groups were audiotaped and transcribed verbatim. The precaution adoption process model (PAPM) was applied during data analysis. Patients who had already experienced a fall more often mentioned that they took precautions to prevent falling. In general, patients were unaware that their medication use could increase their fall risk. Therefore, they did not expect pharmacists to play a role in fall prevention. However, many patients were interested in deprescribing. Patients also wanted to be informed about which medication could increase fall risk. In conclusion, although patients initially did not see a role for pharmacists in fall prevention, their perception changed when they were informed about the potential fall risk-increasing effects of some medications. Patients expected pharmacists to focus on drug-related interventions to reduce fall risk, such as deprescribing
Community pharmacists' perceptions on providing fall prevention services:A mixed-methods study
Background Pharmacists may contribute to fall prevention particularly by identifying and deprescribing fall risk-increasing drugs (FRIDs) in patients with high fall risk. Objective To assess community pharmacists’ perceptions on providing fall prevention services, and to identify their barriers and facilitators in offering these fall prevention services including deprescribing of FRIDs. Setting A mixed-methods study was conducted with Dutch pharmacists. Method Quantitative (ranking statements on a Likert scale, survey) and qualitative data (semi-structured interviews) were collected. Out of 466 pharmacists who were invited to participate, 313 Dutch pharmacists ranked statements, about providing fall prevention, that were presented during a lecture, and 205 completed a survey. To explore pharmacists’ perceptions in-depth, 16 were interviewed. Quantitative data were analysed using descriptive statistics. All interviews were audiotaped and transcribed verbatim. The capability opportunity motivation-behaviour model was applied to interpret and analyse the findings of qualitative data. Main outcome measure Community pharmacists’ views on providing fall prevention. Results Pharmacists stated that they were motivated to provide fall prevention. They believed they were capable of providing fall prevention by FRID deprescribing. They perceived limited opportunities to contribute. Major barriers included insufficient multidisciplinary collaboration, patient unwillingness to deprescribe FRIDs, and lack of time. Facilitators included goal-setting behaviour, financial compensation, and skilled communication. Conclusion Despite the complex decision-making process in medication-related fall prevention, community pharmacists are motivated and feel capable of providing fall prevention. Opportunities for pharmacists to provide fall prevention services should be enhanced, for example by implementing multidisciplinary agreements. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11096-021-01277-4
Parentage verification of South African Angora goats, using microsatellite markers
South African Angora goats are farmed under extensive production systems in relatively large herds. As a result, breeders make use of group and flock-mating systems that limit accurate parentage recording and selection efficiency. In this study the aim was to refine a panel of microsatellite markers suitable for parentage verification in South African Angora goats. The markers were first evaluated based on the number of alleles, allele frequency, PIC, HE, HO and individual exclusion probability, and secondly as part of a panel. Eighteen markers were tested in 192 South African Angora goats representing different family structures with known and unknown parent information. The final set of microsatellite markers, with the strongest exclusion and the least number of microsatellite markers, consisted of 14 microsatellite markers namely BM1258, BM1329, BM1818, BM7160, CSRD247, HSC, INRA63, INRABERN192, MCM527, OarFCB48, SRCRSP5, SRCRSP8, SRCRSP9 and SRCRSP24. This panel had a combined first-parent exclusion probability of 99.7% and it was possible to perform parental identification in a test family.http://www.sasas.co.zanf201
A perspective on the impact of reproductive technologies on food production in Africa
Africa for the largest part is still regarded as part of the developing world and has a history of political
instability, natural disasters, floods and droughts that all had an effect on the development of livestock
production systems and the potential application of biotechnologies. It is expected that the human
population in sub Saharan Africa will experience a growth of 1.2 % per year over the next 30 years. There
is therefore pressure to increase sustainable productivity of livestock. Reproductive technologies such as
Artificial Insemination in Africa were driven primarily by the need to control or prevent venereal diseases
like Trichomoniases and Campylobacter fetus venerealis in cattle. Reproductive biotechnology had a
limited impact in Africa due to several factors including a lack of infrastructure and animal recording
systems, clear breeding objectives and continuously changing production systems and markets. Africa has
a large variety of genetic resources adapted to the diverse environment and production systems and
biotechnology should be applied within this context for an increase in food production.http://www.springer.comseries/55842015-06-30hb201
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