The effect of quantitative feed restriction on growth performance, carcass characteristics and selected meat quality parameters in broiler chickens
- Authors: Velele, Siphelo
- Date: 2017
- Subjects: Broilers (Chickens) Poultry -- Breeding Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8888 , vital:33907
- Description: The study investigated the effects of quantitative feed restriction on growth performance, carcass characteristics, internal organs, breast muscle pH and meat colour in broiler chickens. A total of 90, un-sexed, day-old broiler chicks were procured from an accredited supplier and were used for the current trial. For the first 14 days, all birds were brooded in one house and subjected to a uniform day-to-day management. Water was supplied throughout the trial, whereas, feed was only supplied ad libitum between days 1-14 and 29-35 days in feed restricted birds. Feed phases included starter (1-14 days), grower (15-28) and finisher (29-35), respectively. On day 15, birds were randomly allocated to three treatments; each treatment was replicated three times with 10 birds per replicate. The first treatment (T1) group, which acted as control group, was ad libitum feeding for the whole trial duration (1-35 days). For treatments 2 (T2) and 3(T3), 85 percent and 70 percent of the Cobb 500 broiler feed intake standards were applied for a period of 14 days (days 15-28), respectively. Average daily feed intake (ADFI) was determined daily and then average body weight (ABW) was determined weekly. Feed conversion ratio and average daily weight gain was thus computed for each experimental unit (replicate). On day 35, broiler birds were electrically stunned and slaughtered by a sharp knife and then hung for complete bleeding. Data collected included slaughter, carcass, breast, thigh, wing, drumstick, feet, head, spleen, heart, gizzard, intestines (small & large) and liver weights. Breast muscle was further used for the determination of colour (L*, b* and a*), initial (pHi) and ultimate breast pH (pHu) measurements. Although, quantitative feed restriction (T2 & T3) significantly affected growth performance in weeks 3 and 4, birds submitted to T2 performed similar (P>0.05) to control in the final stage, whilst birds in T3 was the poorest (P<0.05). Furthermore, birds subjected to T2 showed no differences of edible carcass portions to the control, however, T3 group showed lower (P<0.05) slaughter and wing weights. Breast ultimate pH values of birds under T2 were similar to control, but birds in T3 had significantly higher (P<0.05) values. Birds under T2 had less (P<0.05) reddish breast meat colour than control at 45 minutes. At 24 hours post-mortem, birds in T3 had lower (P<0.05) lightness values and birds submitted to T2 had higher (P<0.05) yellowness values. Liver weight was significantly lower in birds under T3 and higher (P<0.05) gizzard weights were found in birds subjected to T2. Birds under T2 performed similar to control and were able to compensate for the weight loss when high plane of feed was re-introduced. It can be concluded from the results that restricting 15 percent of feed from Cobb 500 standard feed intake had moderately affected broiler performance. Moreover, restricting 15percent of feed significantly reduced feed intake in broiler chicken.
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- Date Issued: 2017
The impact of rangeland degradation on vegetation cover and soil quality in semi-arid communal rangelands of the Eastern Cape province, South Africa
- Authors: Maziko, Yonela
- Date: 2017
- Subjects: Communal rangelands -- South Africa -- Eastern Cape Land degradation -- South Africa -- Eastern Cape Vegetation management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15056 , vital:40159
- Description: This study was conducted to investigate the influence of degradation on vegetation and soil quality in two semi-arid rangelands in the Eastern Cape Province of South Africa. The study was undertaken in Kwezana and Esigingqini communal areas that showed signs id degradation. The assessment incorporated the soil and grass layer in different degradation levels, namely nondegraded, slightly degraded, moderately and severely degraded. The non-degraded has a sufficient amount of vegetation cover and species composition. The slightly degraded site consists of a few visible bare patches. The moderately degraded areas showed signs of active sheet erosion such as pedestals and a higher percentage of bare areas and the severely degraded area is characterized by dongas and gullies, with vast areas that have no ground cover or top fertile soil layer. Using a step point method, herbaceous species composition was determined within three transects from three plots 100 m x 40 m in each degradation level. The aboveground phytomass production was determined by harvesting herbaceous species within four randomly placed 0.25 m2 quadrats in each transect. Bare ground was determined by counting and recording the distance between tufts within each quadrat. Litter cover was determined by visual observation and rated on a scale of 1 to 5. A number of physical and chemical soil properties were used to quantify the effects of degradation on soil quality. To determine soil chemical properties, three soil samples were collected at a depth of 20 cm, in each plot and analyzed for pH, soil macro (N, C, K, P, Ca, Mg) and micro (Zn, Fe, Mn and Cu) nutrients. Soil compaction was determined using a soil pocket penetrometer. Readings were taken at 5 mm from 30 points placed at 1 m intervals and distributed in a randomly established straight line in each plot. Soil loss was determined using a rainfall simulator. Splash cups were filled with soil and placed under the rainfall simulator for 8 minutes per rainstorm at 360 mm-1 intensity. Results showed that at Esigingqini a total of 20 herbaceous species were identified, 17 of which were grasses. About 60percent of the identified grasses were Increaser II species, 15percent were Increaser II and 25percent Decreasers. In terms of palatability, 50percent of the grass species had poor palatability and the remaining had either average or high palatability. At Kwezana, 18 herbaceous species were identified of which 28percent were Decreasers and 61percent were Increaser II species. Half of the species had low palatability and only 28percent had high palatability. In both communal areas, litter cover was highest (P < 0.05) in the non-degraded areas followed by the slightly degraded sites and this was to be expected. Similarly, in both communal areas, there was a shift in species composition of decreasers and perennial grasses being replaced by annual species of poor quality and low palatability as the degradation levels increased. Results on soil chemical properties showed that the non-degraded areas had higher (P < 0.05) pH levels (8.5) than the severely degraded soils (5). A similar trend following a degradation gradient was observed for some soil nutrients such as N, P or Mg. Both the macro and micro nutrient concentrations were relatively higher (P < 0.05) in summer than in winter in both communal areas. Results on physical properties showed that soil loss and compaction were relatively lower (P <0.05) in the slightly degraded and non-degraded sites and increased with severity of degradation. In both communal areas, the severely degraded areas lost soil up to 1.1 t ha-1 due to degradation and the non-degraded areas had a soil loss of less than 0.8 t ha-1. The rate of soil loss between the severely and non-degraded areas is significantly different. The differences may be attributed to the differences in the vegetation cover which influences the rate of erosion on the various degradation gradients. These results suggest that both the grass layer and soil quality is negatively affected by degradation. Therefore, there is a need for land use practices that promote the sustainable use of rangeland resources. Such practices may include rotational grazing, reseeding, veld resting and fire. Measures to control the consequences of degradation and rehabilitate these deteriorated rangelands must be a priority.
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- Date Issued: 2017
The impact of the farmer field school approach on small-scale vegetable farmers' knowledge, agency and production in Alice, Eastern Cape
- Authors: Apleni, Asanda
- Date: 2017
- Subjects: Agricultural extension work -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8187 , vital:31873
- Description: This study investigates the impact of the Farmer Field School approach on the knowledge, agency and production of small-scale farmers. Farmer Field Schools were devised in the 1980s by the Food and Agriculture Organization as a form of adult education in agriculture. It is a group-based approach in which a facilitator meets with farmers on a regular basis and sets in motion a process by which farmers ‘learn how to learn’, both from themselves and from one another. However, it remains an open question whether the Farmer Field School approach could be a solution to South Africa’s abiding problem of weak agricultural extension. Early in 2015, the University of Fort Hare and the Nkonkobe Farmers’ Association initiated a number of study groups in the Alice area, based largely on Farmer Field School principles. The main objective of the study was to assess the impact of the Farmer Field School approach on small-scale farmers’ knowledge, agency and production, focusing on home gardeners. The study was conducted in the Raymond Mhlaba Local Municipality in Alice of the Eastern Cape Province of South Africa. The research consisted of a survey of all the study group participants involved with home gardens, including some who joined the groups in 2015 but left in 2016. Both cross-sectional and longitudinal designs were used. Findings from this study have shown how participation in the study groups modelled on the FFS approach can improve the knowledge and skills of home gardeners, while also enabling them to produce significantly larger quantities of vegetables, and even a marketable surplus, albeit from a small base. In order to make more people to join, more incentives should be made available. Such incentives should be made available only to “kick start” the FFS study groups and take heed in prevention of dependence.
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- Date Issued: 2017
The influence of extraction techniques on the chemical composition of essential oils from Pelargonium cv.rose in the Eastern Cape
- Authors: Ngcangatha-Maqhude, Bulelwa
- Date: 2017
- Subjects: Essences and essential oils Pelargoniums Rose geranium oil
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8111 , vital:31524
- Description: Rose geranium is a world known essential oil plant priced for its high grade essential oil mostly utilized in the perfumery industry. However, South Africa has just joined the geranium oil production industry and still battling with the variations in oil yield and composition. Volatile components from Rose geranium were respectively extracted by three methods including hydro-distillation, steam distillation and solvent free microwave. The composition was characterized by GC-FID and GC-MS .No significant differences were found in the oil constituents, colour of the oil was the same in hydro-distillation and steam distillation (light green) but in solvent free microwave extraction the oil was clear because in the receiving flask there was hexane and the quantity of the oil was not the same. The difference was the time taken to extract the oil: Hydro-distillation took 3 hours, steam distillation took 1 hour, 30 minutes and solvent free microwave took only 30 minutes. The main constituents of the essential oil of rose geranium (steam distillation) are Dohne: Citronellol (20.61percent), geraniol (14.79percent), linalool (1.98percent), citronellyl formate (14.25percent), geranyl formate (10.25percent) and guaiadiene 6, 9 (7.22percent). Kieskammahoek: Citronellol (20.36percent), geraniol (9.81percent), linalool (1.54percent), citronellyl formate (16.09percent), geranyl formate F (8.96percent) and guaiadiene 6, 9 (8. 22percent).University of FortHare: Citronellol (21.55percent), geraniol (9.41percent), linalool (1.40percent), citronellyl formate (16.37percent), geranyl formate (8.10percent) and guaiadiene 6, 9 7.92percent). For hydro-distillation, Dohne: Citronellol (24.68percent), geraniol (11.68percent), linalool (11.74percent), citronellyl formate (14.97percent), geranyl formate (5.95percent) and guaiadiene 6, 9 (4.63percent). Kieskammahoek: Citronellol (25.25percent), geraniol (13.44percent), linalool (3.35percent), citronellyl formate (15.62percent), geranyl formate (5.40percent) and guaiadiene 6, 9(4.96percent).University of FortHare: Citronellol (24.73percent), geraniol (8.35percent), linalool (9.76percent), citronellyl formate (16.54percent), geranyl formate (4.42percent) and guaiadiene 6, 9(9.76percent). The solvent free microwave extraction , Dohne: Citronellol (20.87), geraniol (17.85percent), linalool (1.21percent), citronellyl formate (13.44percent), geranyl formate (10.26percent) and guaiadiene 6, 9 (4.59percent).Kieskammahoek: Citronellol (20.13percent), geraniol (5.40percent), linalool (0.28percent), citronellyl formate (14.22percent), geranyl formate (6.04percent) and guaiadiene 6, 9(8.63percent).University of FortHare: Citronellol (21.15percent), geraniol (22.36percent), linalool (1.37percent), citronellyl formate (12.13percent), geranyl formate (8.91percent) and guaiadiene 6, 9 (5.82percent).The percentage of oil composition in hydro-distillation and Solvent Free Microwave Extraction was higher than steam distillation.
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- Date Issued: 2017
The investigation of the role and the efficacy of learning technologies towards community skill development
- Authors: Masikisiki, Baphumelele
- Date: 2017
- Subjects: Web-based instruction Computer-assisted instruction
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5972 , vital:29460
- Description: Research has revealed that during systems design and development of e-learning technologies there is a tendency of neglecting the needs of end users and focus on the design process and the technology factors, and this has traditionally been the reason for poor usability of otherwise well conceptualized systems, as a result a number of IT-based learning tools ended up not being usable and not being utilized effectively. This study aims to investigate the impact of e-learning technologies, how people perceive the usage of e-learning technologies towards community skill development. An evaluation of four different e-learning technologies was conducted to investigate the role and efficacy of e-learning technologies within the surrounding communities. Data was analyzed as nominal data using IBM Statistical Package for Social Sciences (SPSS) software 24. Descriptive analysis, frequency, reliability and correctional analysis and also measures of central tendency were computed. Reliability was evaluated for assessing the internal consistency of the items using Cronbach’s alpha. To analyze the relationship between variables matrices of Pearson’s correlation was used. Pearson’s correlation can only be accepted when the significant effect (P>.05), this indicates that there is a positive or a negative relationship between two variables, if these conditions are not met then the proposed correlation or hypothesis can be rejected. Results indicate a poor perception and poor acceptance of e-learning technologies due to a number of factors, these factors include lack of computer-self efficacy which leads to computer anxiety, affordability of internet connectivity which leads to inaccessible of e-learning technologies. The findings also indicated that LAMS was found to be less useable and less useful by a number of students. However, students who enjoy working in groups found LAMS to be useable because it was supporting their preferred learning style, whereas individualistic students preferred Moodle and Dokeos because it was supporting their personal preferences and assessment styles. Having understood all the characteristics of learning tools, relevant learning technologies that are suitable for students can then be recommended.
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- Date Issued: 2017
The potential of Elephantorrhiza elephantina as an anthelmintic of goats in the Eastern Cape province, South Africa
- Authors: Mazhangara, Irene Rumbidza
- Date: 2017
- Subjects: Bioactive compounds -- South Africa -- Eastern Cape Medicinal plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15068 , vital:40160
- Description: The main objective of the study was to investigate the potential of Elephantorrhiza elephantina in the control of gastro-intestinal worms in goats in the Eastern Cape Province, South Africa. The ethanolic, methanolic and aqueous phytochemical composition of E. elephantina root bark extracts were determined. The phytochemical analysis revealed a high concentration of alkaloids, condensed tannins, flavonoids, phenols and saponins in E. elephantina root extracts. Quantitative phytochemical analysis of alkaloids in water extract was 932.44 ± 1.23 mg. Condensed tannins, phenols and saponins in ethanol extract were 450.52 ± 4.56 mg CE/g, 476.11 ± 0.03 mg GAE/g and 832.85 ± 1.45 mg respectively. Flavonoids was 803.93 ± 0.02 mg QE/g in methanol extract as the highest recordings. In vitro screening of ethanol, methanol and water extracts of E. elephantina for potential anthelminthic activity against adult Paramphistomum cervi worm motility showed time and dose-dependent significant effects after 12 hours of treatment. Ethanolic extracts showed a highly significant (P < 0.05) inhibition of motility (86.67 and 96.67 percent) at concentrations 7.5 and 15 mg/ml, respectively. Methanolic and aqueous extracts exhibited a significant (P < 0.05) motility inhibition (96.67 and 66.67 percent, respectively) at concentration of 15 mg/ml 16 hours post-exposure. In vitro assessment of structural changes to adult gastro-intestinal worms following exposure to E. elephantina extracts was done using scanning electron microscopy (SEM). The SEM observations revealed structural changes in the worms after contact with E. elephantina extracts in comparison with the control worms kept in Phosphate-buffered saline (PBS). The major alterations were around the cuticle, posterior and anterior areas. These changes included longitudinal and transversal folds and thicker cuticula ridges, material aggregates around the posterior and anterior areas. The study showed that ethanol, methanol and water extracts of E. elephantina root contained significant amounts of alkaloids, condensed tannins, flavanoids, phenols and saponins. Validation studies showed that extracts of E. elephantina possess anthelminthic activities. The structural changes found in the worms exposed to extracts of E. elephantina root extracts affected their motility and nutrition, resulting in mortality.
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- Date Issued: 2017
The prospects of commercialising small-scale chicken production in Buffalo City metropolitan municipality, Eastern Cape province, South Africa
- Authors: Seti, Thembalethu Macdonald
- Date: 2017
- Subjects: Farms, Small -- South Africa -- Eastern Cape Poultry -- Breeding -- South Africa -- Eastern Cape Chicken industry -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15244 , vital:40257
- Description: The aim of this study is to explore the prospects of commercialising small-scale chicken production in Buffalo City Metropolitan Municipality, Eastern Cape. In the attempt of exploring these prospects, the researcher sought to understand socio-economic characteristics of small-scale chicken farmers, describe the small-scale chicken enterprise, and determine farmer’s level of commercialisation and factors influencing the farmer’s commercialisation level. Stratified random sampling was used to select 99 participants in the study area. The sampled participants constituted small-scale chicken farmers that were supported by government projects and farmers that were not part of any government support. Descriptive statistics, Household Commercialization Index (HCI) and Multinomial Regression model were used to analyse data and bring meaning to it. The results of the study signify that most of the farmers (66percent) are subsistence oriented, meaning most of their produce is consumed within the household and about 40percent are semi-commercial and only 7percent are at full commercialization meaning they only produce for the market. The result also showed that access to extension services (p<0.03), gender (p<0.03) household size (permanent family members) (p<0.01), transport cost (p<0.04), farming experience (p<0.02, grades and standards (p<0.01), production machines (p<0.05), and distance to the market (p<0.05) were the major determinants influencing output commercialization in the study area. The major constraints to production identified and prioritized by farmers were lack of feed, disease outbreaks, high mortality rate and theft. Based on the study results, to bring about the prospects of commercialising small-scale chicken, government should consistently supply extension officers, government investment in poultry machines and transport is also recommended. In terms of further research, the study suggests that research on profitability of small-scale chicken production would yield immense insights for policy development.
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- Date Issued: 2017
The relationship between selected body composition components and self-efficacy among 12-14 year old rural adolescents in the Eastern Cape Province of South Africa
- Authors: Nkopo, Mandisi, S
- Date: 2017
- Subjects: Child development -- South Africa -- Eastern Cape Children -- Growth Body composition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4536 , vital:28403
- Description: Body composition changes drastically in both males and females during the adolescent years. The changes may have a negative effect on their physical health as well as psychological well-being, with respect to attributes such as self-efficacy. Being either overweight or obese during adolescence has social, economic and psychological consequences, which include low self-efficacy. However, very few international studies and not a single South African study could be found which measured the relationship of anthropometric body composition components, general self-efficacy levels and actual measured body size among adolescents, particularly among rural adolescents. Consequently, the aim of this study was to investigate the relationship between anthropometric body composition components and self efficacy, by conducting a comparison of self-efficacy levels among normal, overweight and obese 12 to 14-year-old rural adolescents in the Eastern Cape Province of South Africa. The sample consisted of boys (n=49) and girls (n=43) between the ages of 12 and 14 years. The body composition components were body weight, stature, body mass index, sum of 3 skinfolds, percentage body fat and hip-to-waist ratio. The sample was also classified into normal, overweight and obese groups, according to body mass index. A self-administered Self-Efficacy Questionnaire for Children (SEQ-C) which was developed by Muris (2001) was used to measure general self-efficacy. Data were analyzed by means of descriptive statistics, the Pearson correlation matrix and Cohen's effect size for significance (Cohen, 1992) and a Mann-Whitney U Test was used to determine statistical differences. Significance was set at p<0.05. Only 17 percent of the participants in the research sample were found to be overweight or obese. Only emotional self-efficacy showed significant (p=0.02) differences between the participants who were classified as having normal weights and the group which comprised the overweight and the obese groups. Overweight and obese boys and girls still had very high levels of self-efficacy, although their body mass index scores were high. Boys scored higher in social self-efficacy and girls in academic self-efficacy. Only girls presented significantly high correlations between body mass index and emotional self-efficacy (r=0.33, p=0.02), total self-efficacy and hip-to-waist ratio (r=0.44, p=0.00), social self-efficacy and hip-towaist ratio (r=0.39, p=0.01) and emotional self-efficacy and hip-to-waist ratio (r=0.33, p=0.02), while boys presented them only with respect to body weight (r=0.31, p=0.02) and stature (r=0.39, p=0.00). The results suggest that a positive relationship exists between body composition, in terms of hip-to-waist ratio, weight and stature, and self-efficacy among South African rural adolescents. However, girls presented significantly strong and positive correlations between hip-to-waist ratio and self-efficacy, whereas boys presented significant, strong and positive correlations between body weight, stature and self-efficacy. Only emotional self-efficacy showed significant differences between normal weight and overweight or obese South African rural adolescents. It seems likely that cultural beliefs may exert an influence on the psychosocial perceptions of adolescents in relation to body size, consequently affecting self efficacy levels.
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- Date Issued: 2017
The study of blockchain towards its application to South African Social Security Agency (SASSA)
- Authors: Mthethwa, Sthembile
- Date: 2017
- Subjects: South African Social Security Agency Electronic funds transfers -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12610 , vital:39292
- Description: In recent years, there has been a rapid improvement in the way currencies are perceived, which has led to a rise in digital currencies commonly known as cryptocurrencies (because they are secured by the use of cryptography). Bitcoin was the _rst successful cryptocurrency which allowed users to transact directly with each other without the involvement of the third party (the bank). Bitcoin introduced a new technology known as the blockchain which is considered to be the ext-generation technology". Blockchain is a chronological database used to store all the transactions that have occurred since the inception of Bitcoin. A study of the Blockchain involving its application to the South African Social Security Agency (SASSA) is presented. This study assesses how the Blockchain functions. The Blockchain has been viewed as the next-generation technology. This study also assesses the application of the Blockchain to other systems other than cryptocurrencies or digital currencies. Recent studies in the literature have proposed applications of the Blockchain to other system (e.g. electronic voting, smart contracts, and intellectual property rights). Although these proposals have been put forward, none has been made speci_cally for SASSA. This study also presents the problems that the Blockchain has (e.g. scalability, security).Recent literature has tried to solve the problem of scalability, by introducing new protocols like mini-blockchain. In addition, this study presents the challenges that SASSA is currently having and it provides details about the attacks that could succeed in the system. The study presents the analysis of the blockchain for its application to SASSA; the analysis includes scalability, performance and security. Based on the analysis, it is shown that the blockchain is not compatible to be applied to SASSA. However, this study proposes a solution to some of the challenges SASSA is currently facing.
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- Date Issued: 2017
The use of behaviour, saliva cortisol and faecal glucocorticoid levels as stress indicators in beef cows
- Authors: Dzviti, Melody
- Date: 2017
- Subjects: Veterinary physiology Beef cattle -- Behavior Glucocorticoids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8165 , vital:31634
- Description: The study evaluated the use of saliva as a minimally invasive technique for cortisol level determination. This was done by assessing the relationship between serum and saliva cortisol based on short sampling intervals. In addition, the study also determined the effect of successive handling on faecal glucocorticoid metabolites (FGM), rectal temperature (RT), avoidance distance (AD), chute and crush scores as well as urination, defaecation and vocalization in multiparous cows. For trial one six non-pregnant, clinically healthy Nguni cows were used. They were administered with standardised doses of adrenocorticotropic hormone on treatment days and saline was used as a placebo on alternative days. Simultaneously, blood and saliva samples were collected to quantify cortisol levels. No relationship (r = 0.0131, P>0.05) was observed between serum and saliva cortisol. However, results showed that there was adrenal stimulation in saliva coupled by significant (P<0.05) effects of sampling intervals. For the second study 21 non-pregnant and clinically healthy Nguni cows of one herd were used for the trial. They were divided into parity groups and their weights were used as a covariate in data analysis. For five consecutive weeks, fresh faecal samples were extracted and rectal temperatures measured. In addition, fear of approaching humans was assessed by AD scores and behaviour scores in the crush chute, as well as vocalisation, urination and defaecation were observed. The effect of successive handling significantly (P<0.05) affected the physiological parameters, namely FGM and RT. Contrariwise, Chi-square tests revealed that parities had a significant (χ2 < 0.05) influence on AD and crush scores as well as on the occurrence of excretory behaviour. It was concluded that saliva cortisol can be used as a stress indicator in beef cows. However, plasma cortisol can be significantly volatile thereby becoming less sensitive to changes across time. This can cause a lack of relationship between plasma and saliva cortisol. On the other hand, repetitive handling of beef cows has an influence on faecal stress levels. In addition, beef cows of differing parities behave differently to handling stress.
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- Date Issued: 2017
Thermodynamic and electrical performance monitoring of a domestic split-type air conditioner and development of a simulation based R22 permanent replacement
- Authors: Bantan, Mafor Glory
- Date: 2017
- Subjects: Air conditioning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4857 , vital:28537
- Description: The difficulty that exists in accurately monitoring the performance of air conditioners has made performance prediction an arduous task. Nevertheless, the performance still needs to be monitored and predicted as it helps solve a lot of problems resulting from this technology like effect of the technology on the grid, energy consumption, water utilisation and GHGs emission. With the introduction of regression modelling as a means of system monitoring and prediction some years ago, the accuracy was still a call for concern. It is worth realising that increasing the number of predictors will enhance this method’s accuracy. As such, this document intends to increase the accuracy of this method’s monitoring and predicting ability by increasing the number of predictors to cut across system thermal, environmental and human behavioural variation. These predictors experimentally gotten are used to build an environ-behavioural model that monitors the coefficient of performance and energy consumption of a domestic split-type air conditioner with higher accuracy. Refrigerants have undergone evolution in the past decades in a bid to come up with a refrigerant that has zero ODP, lower – than – R22 GWP and much better than R22 thermodynamic performance. No pure refrigerant has been found to possess these qualities as such mixtures or blends are the best shot at the moment. R410A could stand the test of time to be the long term R22 replacement but for the fact that besides R410A’s higher GWP than that of R22, the former’s system performance is lower than that of the latter’s due to the lower thermodynamic performance of the former. This means the search continues. In this document, a combination of carefully chosen refrigerant components are carefully blended to come up with a simulation based R22 long term replacement, which will be referred to in this document as BTEP.
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- Date Issued: 2017
Tillage and crop rotation effects on selected soil properties and wheat yield in a short term field experiment in the Eastern Cape province, South Africa
- Authors: Mtyobile, Mxolisi
- Date: 2017
- Subjects: Crop rotation -- South Africa -- Eastern Cape Cropping systems -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/13414 , vital:39659
- Description: Severe land degradation associated with current conventional production systems have resulted in low production amongst the small scale farmers in the Eastern Cape. Inappropriate management practices cause depletion of organic matter and other essential nutrients leading to a decline in crop productivity. There is growing evidence that conservation agriculture (CA) practices involving no-tillage (NT) coupled with crop rotation and surface residue retention increases soil organic carbon (SOC) and other essential nutrients and therefore has potential to alleviate soil quality deterioration. A study was carried out to investigate the effects of tillage and crop rotation with crop residue retention on selected soil properties and on wheat yield in the Alice Jozini ecotope of the Eastern Cape. Specific objectives were to determine (i) the effect of crop rotation and tillage on soil SOC, NH4, NO3, total N, P, K, Ca, Mg, Zn, soil pH and EC distribution at 0-5 cm, 5 cm -10 cm, 10 cm-20 cm (ii) the effect of crop rotation and tillage on soil bulk density, porosity and on soil water content (iii) the effect of crop rotation and tillage on wheat biomass and grain yield. Treatments were arranged as a split-split plot in a randomized complete block design with three replicates. Tillage treatments included no-tillage (NT) and conventional tillage (CT) and were applied on the main plots while crop rotation treatments were applied as subplots. Crop residue retention treatments were applied as sub-sub plots. The rotational treatments were maize-fallow-maize (MFM), maize-fallow-soybean (MFS), maize-wheat-maize (MWM) and maize-wheat-soybean (MWS). However, the current study focused on tillage and crop rotation treatments under residue retention to give 8 treatments. Data from the field trials showed that NT with residue retention had significantly (p < 0.05) higher SOC, Total N, P, K, Ca and EC relative to CT. The MWS rotation under no-tillage (NT) with residue retention followed by MFS resulted in the progressive improvement in soil nutrient status. The correlations of SOC with various soil nutrients under study showed that the nature of the relationships between SOC and nutrient availability was consistent. Results on soil physical parameters showed that tillage had no significant effect (p > 0.05) on soil bulk density (ρb) and porosity whereas a significant effect on soil water content under NT was observed. Crop rotation had no significant effects (p > 0.05) on soil bulk density, porosity and soil moisture across the tillage treatments. The MWS rotation registered an increase in soil porosity in comparison with the MWM and MFM. Tillage x crop rotation interaction effects were significant (p < 0.05) on the measured porosity and soil water content. Soil bulk density showed negative correlation with soil porosity and soil water content (SWC) whereas porosity had a positive correlation with SWC. On yield parameters, results revealed that no significant (P>0.05) interaction of main effects with respect to wheat biomass and grain yield. Tillage had a significant (P<0.05) effect on wheat biomass only in season 2. Tillage and crop rotation effects were not significant (P>0.05) with regards to grain yield throughout the experimental period. Higher grain wheat biomass and grain yield were found in MWS rotation under NT with surface residue retention although not statistically significant. Correlation analysis revealed that wheat yield was positively correlated to SOC, P, and Total N. Therefore, combination of NT with MWS rotation with residue retention has the potential to significantly improve soil chemical properties and wheat grain yield whereas MWM followed by MWS crop rotation under NT showed an increase in soil porosity and soil water content.
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- Date Issued: 2017
Yield responses, mineral levels of forages and soil in old arable land planted to four legume pasture species in Lushington communal area, South Africa
- Authors: Gulwa, Unathi
- Date: 2017
- Subjects: Forage plants -- South Africa -- Eastern Cape Minerals in animal nutrition Communal rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2799 , vital:28091
- Description: This study was conducted in the old arable land located in Lushington communal area in the Eastern Cape province of South Africa. The objectives of the study were to assess the effect of legume introduction on biomass yield, forage and soil mineral levels of the arable lands planted to four leguminous pastures in four seasons. Planting was done in March and October 2008 in Lushington. All legumes were subjected to grow under rain fed conditions. Trifolium vesiculosum (arrowleaf clover), Lespedeza cuneata (sericea lespedeza), Trifolium repens (white clover) and Lotus corniculatus (birdsfoot trefoil) are the four forage legume species that were sampled for the purposes of this study. The four legume species persisted out of the fourteen species that were initially tested for adaptability and persistence in the environmental conditions of Lushington communal area. The legumes, grasses and soils from these legume plots were sampled to determine the effect of legume introduction on the forage yield, mineral contents of the companion grasses and soils over four seasons. Plant and soil samples were collected once in spring (November) 2013, summer (February), autumn (March) and winter (May) 2014 for biomass production, macro and micronutrients determination. Results indicated that legume inclusion and season affected (P < 0.05) the total dry matter (TDM) yield production. Plots with Lespedeza cuneata had the highest TDM (1843 kg/ha) and control plots had the least dry matter production (1091 kg/ha). Summer season provided the highest (P < 0.05) TDM compared to the other seasons. Both legume and grass quality was also affected (P < 0.05) by legume inclusion in different seasons. Accordingly, grasses harvested from Trifolium repens plot showed higher CP level (10.90 percent) than those harvested from other plots whereas the lowest grass CP content (6.90 percent) was measured in the control treatment. L. cuneate had the highest (P < 0.05) CP level (11.00 percent) and T. repens had the least CP (6.63 percent) level. Grasses harvested in autumn had the highest (P < 0.05) CP level (12.50 percent) and those harvested in winter had the least CP level (4.60 percent). Similarly, all legume pastures harvested in spring had superior (P < 0.05) CP (10.80 percent) levels and those harvested in winter had the least CP (3.50 percent) level. Legume inclusion had an effect (P < 0.05) on both grass and legume macro nutrient contents. Trifolium repens plot had the highest grass K (1.07 percent), Ca (1.50 percent) and Mg (1.83 percent), whereas there were lower K (0.12 percent), Ca (1.25 percent) and Mg (1.08 percent) contents in grasses harvested from the control and T. vesiculosum plots, respectively. In legumes, macro nutrient concentrations: K (0.68 percent), Ca (1.75 percent) were superior in the T. vesiculosum plot in comparison to other plots. Season also affected (P < 0.05) both grass and legume macro nutrient content. There was higher K (0.90 percent), Ca (1.30 percent) and Mg (0.94 percent) content in grasses harvested in autumn whereas there were lower levels in winter harvests. In legumes, superior K (0.74 percent) and Mg (1.87 percent) content were attained during spring while the least were measured in winter (0.07 percent) and autumn (0.75 percent), respectively. Likewise, both legume inclusion and season had an significant effect (P < 0.05) on the forages micronutrient levels. During spring, there was superior soil P content (36.28 mg/kg) while during autumn; there was less P (22.58 mg/kg) content. The highest SOC level (1.49 percent) was measured in the T. repens plot whereas the lowest SOC (1.15 percent) was attained in the control plot. The results of this study showed that grass legume mixtures produced forages with high nutrient content and herbage yield. Legume planting in the old arable lands has a potential to improve soil quality parameters such as soil P and SOC content.
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- Date Issued: 2017