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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Mechanisms of resistance to Rhipicephalus ticks in Nguni cattle reared in the semiarid areas of South Africa.

Marufu, Munyaradzi Christopher. January 2012 (has links)
Ticks and tick borne-diseases (TBD) are major challenges to cattle production among smallholder farmers in the semiarid areas of South Africa. Nguni cattle have been reported to be resistant to ticks and TBD, however, the mechanisms responsible for the trait are not fully understood. The broad objective of this study was to determine the mechanisms of resistance to ticks in Nguni cattle reared in the semiarid areas of South Africa. Tick infestation levels, body condition scores (BCS), packed cell volumes (PCV) and the molecular prevalence of A. marginale were determined in Nguni (n = 70) and local crossbred (n = 79) cattle reared in the semiarid areas of South Africa. Relationships among skin thickness, hair length, coat score and tick counts were assessed in seven to nine month old Nguni (n = 12) and Bonsmara (n = 12) heifers. As a follow up, cutaneous hypersensitivity responses to unfed larval extracts (ULE) of the ticks Rhipicephalus decoloratus and Rhipicephalus microplus were examined in heifers to determine host immunity to the ticks. Tick counts and inflammatory cell infiltrates in skin biopsies from feeding sites of adult R. microplus ticks in nine-month-old Nguni and Bonsmara heifers were also evaluated. The molecular prevalence of A. marginale was similar in the Nguni (47.7 %) and local crossbred (52.3 %) cattle. Nguni cattle suffered less severe losses from and were more vi resilient to A. marginale infection than local crossbreds. Nguni heifers had lower coat scores, hair length and tick counts than the Bonsmara heifers. The relationship between tick counts and coat score was positive and linear in the Nguni (y = 1.90x – 0.40) and quadratic in Bonsmara (y = -7.98x2 + 12.74x - 3.12) heifers. Bonsmara cattle showed a more intense immediate reaction and no delayed hypersensitivity reaction to ULE of Rhipicephalus ticks. Nguni heifers presented a less intense immediate reaction and a delayed hypersensitivity reaction at 72 h post inoculation with ULE of Rhipicephalus ticks. Reactions to R. decoloratus ULE produced a more intense skin response at all time intervals in both breeds than that of R. microplus. Parasitized sites in Nguni heifers had higher (P < 0.05) counts of basophils, mast and mononuclear cells than those in the Bonsmara heifers. Conversely, parasitized sites in Bonsmara heifers had higher (P < 0.05) neutrophil and eosinophil counts than those in the Nguni heifers. Tick count was negatively correlated (P < 0.05) with basophil and mast cell counts. There was a positive correlation between eosinophil counts and tick counts in both breeds, and between tick counts and mononuclear cell counts in the Bonsmara breed. It was concluded that smooth and short coats, delayed type hypersensitivity and cutaneous basophil and mast cell infiltrations are responsible for increased tick resistance in the indigenous Nguni cattle breed of South Africa. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.
82

Effects of physicochemical properties of fibrous feed on feeding behaviour and gut health of growing and finishing pigs.

Bakare, Archibold Garikayi. 30 October 2014 (has links)
The broad objective of the study was to determine feeding behaviour and gut health of pigs fed different fibres at varying inclusion levels. Maize cob, maize stover, sunflower hulls, veld grass, sawdust, lucerne and dried citrus pulp were used in growing and finishing pig diets to provide a wide range of physicochemical properties. Time spent eating, drinking, lying down, sitting/standing and other activities was observed using video cameras. Blood samples were collected at the end of the trial for both growing and finishing pigs for analysis of glycated haemoglobin, albumin, globulin, total protein, creatine kinase, urea and uric acid. Intestinal segments were collected at the end of trial for growing pigs to determine mucosal architecture of the intestines. Digestible energy (DE), bulk density (BD), acid detergent fibre (ADF) and water holding capacity (WHC) were the most important variables predicting time spent on different behavioural activities in growing pigs (P < 0.001). Water holding capacity, neutral detergent fibre (NDF) and ADF were the most important variables involved in predicting time spent on different behavioural activities in finishing pigs (P < 0.001). Physicochemical properties influenced time spent on different behavioural activities and they provided relationships with time spent on different behavioural activities in both growing and finishing pigs. Glycated haemoglobin, albumin, globulin, total protein and uric acid were factors that influenced time spent eating in growing pigs (P < 0.05). In finishing pigs, only serum total protein was selected as the best predictor variable influencing time spent eating (P < 0.05). The blood metabolites were correlated with time spent eating and drinking. They provided threshold values with time spent eating and drinking by pig. Hence, they can also be used as potential biomarkers that modulate neuronal pathways which reduce time spent eating and drinking. In this study, bulk density (BD) and NDF were the best predictor variables influencing villi height (VH) and apparent villi surface area (AVSA) in pigs (P < 0.05). Grouped pigs fed fibrous diet spent more time eating, lying down, standing, walking and fighting (P < 0.05). Skin lesions appeared the most on neck and shoulder region followed by chest, stomach and hind leg region, and finally head region (P < 0.05). Fibrous diet did not reduce aggressive behaviours, rather aggressive behaviours emanated out of frustration when queuing at the feeder. It was concluded that physicochemical properties of fibrous diets and nutritionally-related blood metabolites influence feeding behaviour. Mucosal architecture was also influenced by physicochemical properties of the fibrous diets. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.
83

Effects of hydric stress on the growth, blood chemistry and meat quality characteristics of indigenous chickens.

Chikumba, Nation. 10 October 2014 (has links)
The broad objective of the study was to determine the effects of restricted water intake on the growth, blood chemistry and meat quality characteristics of indigenous chickens in semi arid environments. A total of 15 flocks in communal villages and 12 flocks in resettlement schemes of Msinga District in South Africa were monitored for 30 months to determine the effects of production system and season on flock size, dynamics and constraints faced by indigenous chicken producers. As a follow up, 281 and 233 chicks hatched in November 2011 from 18 and 9 households in communal villages and resettlement schemes, respectively were monitored using a structured checklist to determine survival and causes of mortality from hatching up to 12 weeks of age. Kaplan-Meier survival distributions and the odds ratios for effects of potential risk factors were determined using survival analysis and logistic regression models, respectively. Flock composition and structure were significantly affected by production system and month. Farmers in resettlement schemes had approximately one cock and three hens more (P < 0.05) than those in communal villages. The number of growers and chicks were similar (P > 0.05) between the two production systems but chicks were the predominant age group (38 %) of each flock. The cock to hen ratio in households in communal villages was 1:3.5, while that in resettlement schemes was 1:3.7, suggesting that inbreeding might have been reducing flock productivity. Flock sizes in communal villages peaked in March (45.1 ± 3.02) during the post rainy season and declined steadily to a low of 34.7 ± 3.63 in September during the hot-dry season. The largest flock sizes in resettlement schemes were observed in January (52.4 ± 5.09) during the hot-wet season and the smallest in August (36.1 ± 5.98) during the cold- dry season. Households in communal villages had more chicks (P < 0.05) than cocks, hens and growers throughout the year except in June when the number of growers was equal to that of chicks. In resettlement schemes, the number of chicks was lower (P < 0.05) than the number of hens and growers, except in June and July when it was equal to that of growers. Total entries were not affected (P > 0.05) by production system. Hatched chicks were the major mode of entry, accounting for more than 97 % of entries into flocks. The contribution of purchases, gifts and exchanges was negligible. Mortality was the main cause of exits from flocks, accounting for 70 and 63 % of total exits among households in communal villages and resettlement schemes, respectively. The major causes of mortality were aerial predators, sub-optimalnutrition and inclement weather conditions, which were similar between production systems. The number of birds that exited flocks through slaughter for household consumption was higher (P < 0.05) among households in resettlement (34% of total exits) than communal villages (21 % of total exits). The proportion of chickens exiting flocks through sales was higher in communal (9 %) than resettlement (4.3 %) households. Chick survival from hatching to 12 weeks was higher (P < 0.05) in communal villages (55 ± 3.14 %) than in resettlement schemes (41 ± 4.19 %). Mean chick survival time did not differ (P > 0.05) between communal (56 ± 3.30 days) and resettlement (49 ± 3.23 days) flocks. Provision of water ad libitum and treatment of sick birds were important covariates in prolonging the survival time of chicks. The effects of restricted water intake on growth performance, blood chemistry, physicochemical properties, and sensory characteristics of meat from Naked Neck (NNK) and Ovambo (OVB) chickens were also assessed. In the experiment, 54 pullets of each strain with an average weight of 641± 10g per bird were randomly assigned to three water restriction levels for 60 days in a completely randomized design. The treatments were ad libitum, 70% of ad libitum and 40% of ad libitum water intake. Each treatment group was replicated three times. The pectoralis (breast) muscle was sampled for meat quality, fatty acid composition and sensory quality analyses. Ovambo chickens had superior body-weight at 16 weeks of age, average daily gains (ADG) and average daily water intake (ADWI) than NNK chickens. Body weight of birds at 16 weeks of age, ADG, average daily feed intake (ADFI), ADWI and water to feed ratio (WFR) declined progressively (P < 0.05) with increasing severity of water restriction, while food conversion ratio (FCR) values increased (P < 0.05) as the severity of water restriction increased. Naked Neck chickens had better FCR at the 40 % of ad libitum water intake level than OVB chickens. The dressing percentage per bird was higher (P<0.05) in water-restricted birds than those on ad libitum water consumption, irrespective of strain. Heart weight was significantly lower in birds on 40% of ad libitum water intake than those on ad libitum and 70% of ad libitum water intake, respectively. Packed cell volume was higher (P < 0.05) in NNK than OVB chickens offered waterad libitum, but similar in birds offered 70 and 40 % of ad libitum. There were no differences in erythrocyte count (RBC) and mean corpuscular volume (MCV) values between strains, but MCV was higher in birds on 40 than 70 % of ad libitum water intake, irrespective of strain. Naked neck chickens had higher (P < 0.05) white blood cell count (WBC) values than OVB chickens at 40 % restriction level, but lower WBC than OVB at 70 % water restriction level. Uric acid, creatinine, triacylglycerides, total cholesterol, low density lipid cholesterol, total protein and globulin increased (P < 0.05) with each increment in water restriction, but the increase in creatinine and total cholesterol was more pronounced in OVB than NNK chickens. The opposite was observed for uric acid. Alanine transaminase, alkaline phosphatase and aspartate transaminase activities were not influenced by strain and water restriction. It was concluded that the two strains could withstand up to 40 % of ad libitum water restriction, but NNK chickens tolerated water stress better than OVB chickens. Water intake levels of 40% of ad libitum produced meat with significantly lower (P < 0.05) cooking loss, and higher (P < 0.05) redness (a*) values in NNK chickens compared with OVB chickens. Water intake level had no effect (P > 0.05) on lightness (L*) and yellowness (b*) values, shear force, moisture and protein contents in both strains. The fat content of NNK meat was 41 % lower (P < 0.05) than that of OVB meat at 70 % of ad libitum, but 31 % higher at 40 % of ad libitum water intake. The ash content was significantly elevated (P < 0.05) in birds on 70 % of ad libitum compared to those on ad libitum and 40 % of ad libitum water intake, which had similar (P > 0.05) ash contents. Birds on 40 % of ad libitum water intake had significantly higher (P < 0.05) proportions of octadecanoic acid (C18:0), cis, cis-9,12-octadecadienoic acid (C18:2 ῳ-6), cis-8,11,14,17-eicosatetraenoic acid (C20:4 ῳ-6), cis-7,10,13,16-docosatetraenoic acid (C22:4 ῳ-6), cis-4,7,10,13,16,19-docosahexaenoic acid (C22:6 ῳ-3), total polyunsaturated fatty acid (PUFA), total omega-3 PUFA and total omega-6 PUFA proportions, but lower (P < 0.05) cis-7-hexadecenoic (C16:1c7), cis-9-octadecenoic (C18:1c9), cis-11-octadecenoic acid (C18:1c11), cis-13-docosenoic acid (C22:1c13), total monounsaturated fatty acids than those on the 70% of ad libitum and ad libitum water intake, respectively. The proportion of trans-9-octadenoic acid (C18:1t9) was higher (P < 0.05) in NNK chickens on 40 % of ad libitum water intake than OVB chickens. It was concluded that water restriction at 40 % of ad libitum water intake resulted in favourable cooking loss values and meat redness (a*) values, omega-3 and 6 PUFA proportions and a high ῳ-6/ῳ-3 ratio. The high fat content of NNK chickens at 40 % of ad libitum water intake compared to OVB chickens suggests a superior adaptation to hydric stress. Naked Neck breast meat had higher initial impression of juiciness scores than that from OVB chickens, but only in birds on ad libitum and 70 % of ad libitum water intake. Sensory scores for first bite, connective tissue and tenderness decreased with increasing severity of water restriction (P < 0.05). Aroma, flavour and atypical flavour were not affected by strain or water restriction level (P > 0.05). There were significant strain differences for sustained impression of juiciness and tenderness, with the highest scores occurring in NNK chickens (P < 0.05). Aroma had a significant influence on the flavour of breast meat (P < 0.05). Fat content was significantly correlated with initial impression of juiciness, first bite and sustained impression of juiciness of breast meat. It was concluded that water restriction up to 40 % of ad libitum had a significant and adverse impact on juiciness and first bite scores of meat. / Ph.D. University of KwaZulu-Natal, Pietermaritzburg 2013.
84

Effects of dietary fibre on pig excreta characteristics and odours from slurry.

Mpendulo, Conference Thando. 02 December 2013 (has links)
A study was conducted to test the effects that different high fibre sources and their varying inclusion levels had on the characteristics of the excreta (faeces, urine and the slurry), and on odour from the slurry of growing pigs. Faeces and urine characteristics were tested from 52 pigs fed rations containing grass hay (GH), lucerne hay (LH), maize cobs (MC), maize stover (MS) and sunflower husk (SH) diets at inclusion levels up to 400 g/kg as fed basis. Faecal output, faecal consistency and nitrogen were influenced by fibre type (P <0.01) and inclusion level (P <0.01). Nitrogen content in faeces and urine was also affected by dietary fibre inclusion. Increasing fibre inclusion levelled to a reduction in urinary nitrogen content, indicating nitrogen repartitioning from urine to faeces, thereby minimizing nitrogen volatilization. The slurry from pigs fed on LH, MC and SH at levels up to 160 g/kg was tested for chemical composition and odour offensiveness. The slurry was incubated for 16 days. The pH and nitrogen content varied among fibre types and incubation period (P <0.05). Isobutyrate and butyrate concentrations varied with fibre type and the incubation period tested (P <0.01). Using panellists, the SH containing rations resulted in low odour offensiveness score. Maize cob-containing diets resulted in the largest odour scores, with (mean rank of 2.2 and 4.3 for SH and MC, respectively). To reduce odour offensiveness from piggeries, sunflower husk was recommended as an alternative feed ingredient for growing pigs. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
85

Nutritive value of Acacia species and response of pigs fed on incremental levels of Acacia tortilis leaf meal-based diets.

Mbongeni, Khanyile. January 2013 (has links)
The broad objective of the current study was to determine the response of pigs fed on incremental levels of Acacia tortilis leaf meal-based diet. Eight trees of each of the following five dominant leguminous leaf meals; A. tortilis, A. robusta, A. nilotica, A. nigrescens and A. xanthophloea, were individually hand harvested from the same grazing camp at Makhathini Research Station, Jozini, South Africa. The leaf meals were harvested between April and May 2013 after the rainy season at advance stage of maturity. Following the nutritive evaluation of Acacia species, A. tortilis was selected for the feeding experiment. Thirty finishing male F1 hybrid (Landrace × Large White) pigs with an initial weight of 60.6 (s.d. = 0.94) kg were randomly allotted to six dietary treatments containing 0, 50, 100, 150, 200, 250 g/kg DM inclusion levels of A. tortilis leaf meal. Each treatment diet was offered ad libitum to five pigs in individual pens for 21 days. Average daily feed intake (ADFI), body weight, average daily gain (ADG) and gain: feed ratio was measured every week. Blood was collected at the end of the experimental period for the determination of nutritionally-related blood metabolites and activity of Aspartate aminotransferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALP). Following a feed withdrawal period of 12 hours, pigs with a mean body weight of 80 ± 15 kg were slaughtered, eviscerated for the collection of livers, kidneys, lungs and heart from each pig and weighed individually using a digital scale. Acacia tortilis and A. xanthophloea leaf meals had the highest CP and fat content (P < 0.01) among all the Acacia species. The NDF and ADF varied significantly across Acacia species (P < 0.05). Acacia robusta had significantly the highest levels of non-structural carbohydrates, whilst A. tortilis had the lowest. The concentration of proanthocynidins varied across the species. Acacia tortilis had significantly high levels (23 g/kg DM) of phosphorus compared to the other species. Acacia nilotica had the highest (P < 0.001) concentration of iron, but it had the lowest (P < 0.01) level of manganese. There was a quadratic decrease in both ADFI and ADG (P < 0.001) with as A. tortilis leaf meal increased. The gain: feed ratio was linearly reduced (P < 0.001) with incremental levels of A. tortilis leaf meal in the diets. Serum concentrations of Fe, AST and ALP increased quadratically (P < 0.01) as A. tortilis leaf meal increased. There was a linear increase in ALT activity with increased leaf meal inclusion. Hepatosomatic index (HSI: liver weight/ body weight x 100), scaled kidney weight and scaled heart weight increased linearly (P < 0.001) as A. tortilis leaf meal increased. There was, however, a quadratic increase in the relative weight of lungs (P < 0.001) as leaf meal increased. In conclusion, the piecewise regression (brocken-stick) NLIN procedure (SAS, 2008; SASA institute Inc.) showed that A. tortilis leaf meal can be included in finisher pig diet up to 150 g/kg DM of feed without negatively affecting growth performance, nutritionally-related blood metabolites, liver enzymes and internal organs of pigs. / M.Sc.Agric. University of KwaZulu-Natal, Pietermaritzburg 2013.
86

Breed susceptibility to enterotoxigenic and enteroaggragative Escherichia coli strains in South African pigs.

Chaora, Nyaradzo Stella. January 2013 (has links)
Escherichia coli diarrhoea is the most important source of mortality in piglets. The most frequently isolated strain in enterotoxigenic E. coli diarrhoea is F4ab/ac. Recent studies in South Africa reported non-fimbrial strains such as PAA and EAST-1 to be prevalent. The objective of the study was to determine whether there are breed differences among pigs with respect to E. coli adhesion phenotypes and correlate them to polymorphisms at selected candidate genes in the South African population. A total of 225 pigs aged 3-12 weeks of the imported (Large White, Landrace and Duroc), local and crossbreds, were sampled from the Eastern Cape and Limpopo provinces of South Africa and genotyped for PCR-RFLP polymorphisms at four candidate genes associated with E. coli F4ab/ac resistance/susceptibility. These genes were Mucin 4 (MUC4), Mucin 13, (MUC13), Mucin 20 (MUC20) and Transferrin Receptor (TFRC). The TFRC and MUC13 genes were less polymorphic, the C allele was close to fixation and the homozygous CC genotype was the most frequent in all three pig populations. There was a significant difference (P <0.05) in allelic and genotypic distribution amongst breeds for the TFRC locus. The g.8227G>C polymorphism in MUC4 segregated in all three breeds and the marker was moderately polymorphic. There was a significant difference (P <0.05) in genotypic distribution amongst breeds for MUC4.The g.191C>T polymorphism in MUC20 segregated in the local and crossbred pigs and was close to fixation in the imported pigs. There was a significant difference (P <0.05) in allelic and genotypic distribution amongst breeds for MUC20, which was moderately polymorphic. There was a reduction in heterozygosity in both the TFRC and MUC13 loci, although MUC4 and MUC20 genes had higher heterozygosity levels. The MUC4 gene had a negative FIS value, indicating outbreeding at this locus. The MUC20, MUC13 and TFRC genes had a positive FIS value, indicating inbreeding at these loci. Overall, the studied population was outbred. Imported pigs in TFRC and MUC20 deviated from Hardy-Weinberg equilibrium (HWE). All breeds were in HWE at the MUC4 and MUC13 genes. There was no linkage disequilibrium observed amongst the analysed loci. iv A total of 109 piglets of three breeds (Large White, indigenous and crossbred) aged 3-5 weeks, were investigated for the susceptibility to E. coli F4, PAA strains and EAST-1 toxin. Adhesion tests were conducted on pig intestinal cells, which were viewed under a phase contrast microscope. Three phenotypes were identified as, adhesive, weakly adhesive and non-adhesive. There was a significant association (P <0.05) between breed and level of adherence of the F4 and PAA strains. Highest frequencies of adhesion phenotypes were observed in the indigenous pigs for both F4 and PAA E. coli strains. Large White pigs had the lowest frequency of non-adhesion in F4 and PAA E. coli strains. The F4 strain had a higher (P <0.05) level of adherence compared to PAA and EAST-1 in Large White pigs. Age of pigs had a significant effect on the level of E. coli adherence in indigenous and crossbred pigs (P <0.05). Adhesion of F4 and EAST-1 was higher in weaned indigenous and crossbred pigs, respectively, than in suckling piglets. There was no significant difference between F4 adhesion and the genotypes at all four candidate genes genotypes. The study showed that both imported and local pig populations carry receptors and are susceptible to F4, PAA and EAST-1 E. coli infections. Indigenous pigs were less susceptible than Large White to E. coli infection. Although polymorphic and segregating in the populations, the MUC4 g.8227G>C and MUC20 g.191C>T mutations were not associated with the adhesion phenotypes and cannot be used in the selection of susceptible animals. / M.Sc.Agric. University of KwaZulu-Natal, Pietermaritzburg 2013.
87

The Elementary E.G.G. Program Impact on Agricultural Literacy and Interest

Danielle Marks (8800760) 05 May 2020 (has links)
<p>This thesis examines the Elementary Educate Gain Grow (E.G.G.) program and its impact on student agricultural literacy and interest in relation to the program’s pilot classroom implementation. The overall shortage of graduates pursuing careers in the poultry industry was the motivation behind the program development. The gap between industry demand and the potential entering poultry workforce may be linked to low awareness and interest relating to poultry science. This is particularly true in the egg industry. As consumer and legislature demands continue to affect egg production practices and demand for eggs continues to grow, it is especially crucial for consumers to become more aware of industry practices. One way to increase awareness may be to include educational resources within the K-12 system that are designed to increase awareness and interest in the industry. By integrating poultry science into required academic standards, students are given a real-world context to apply STEM skills. This has the potential to improve the learning experience and stimulate student interest and awareness. Such resources have the potential to promote future student engagement in poultry science opportunities. Therefore, the Elementary E.G.G. program was developed as an integrated STEM and poultry science curriculum with five online modules, a supplemental interactive notebook, an embedded simulation game, and a final team project as a resource for upper elementary teachers and students. All content and materials were developed between fall 2018 and summer 2019 and were made available to 480 Indiana 4<sup>th</sup> and 5<sup>th</sup> graders (13 teachers, 19 classrooms) across 8 different school districts in the fall of 2019. The program was designed for a ten consecutive day STEM unit starting with online modules (days 1 to 5) and followed by a team project (days 6 to 10). There were three overall research questions to assess the impact of the Elementary E.G.G. program: 1) what was student agricultural literacy before, during, and after program implementation; 2) did the program have an effect on student situational interest; and 3) what was the teacher perceived value and effectiveness of the program as an education resource. </p> <p>Chapter One provides a literature review outlining past research that provided background for the development of the Elementary E.G.G. program. </p> <p> Chapter Two describes the experimental methods and results of the piloted Elementary E.G.G. program and how it impacted student agricultural literacy through evaluating three content assessments and student notebook responses. Additionally, we discuss teacher feedback, collected at the completion of the program. Quantitative data was collected to assess student poultry knowledge prior (pre-program), during (post-modules), and after implementation (post-program) using 14 multiple choices questions focused on module content. The questions were administered online using Qualtrics (Qualtrics, Provo, UT). Only student data that was completed correctly across all assessments and notebook responses from student’s in corresponding classrooms to the other assessments were used for analysis. Student notebook responses from 10 corresponding classrooms (52.63% response rate), were deemed usable for analysis since these classrooms had students who correctly completed all assessments and qualitative data from notebook responses could only be matched to classrooms not individual students. Student content scores (n=111; 23.13% response rate) were analyzed using an ANOVA post hoc Tukey’s test with SPSS Version 26. Content knowledge scores increased from 7.99 (SD=1.85) during the pre-program assessment to 9.76 (SD=2.44) post-modules (<i>p</i> < 0.0001). Student notebook responses provided qualitative data of their agricultural literacy development throughout the modules. Student responses from the useable 10 classrooms (n=172; 35.83% response rate) were inductively coded to reveal patterns that supported increased student agricultural literacy related to each module’s predetermined learning objectives. The increase in content scores along with student identification of learning objectives support the program’s ability to increase student agricultural literacy. Teacher feedback (n=9; 69.2% response rate) indicated that teachers agreed that each of the components (modules, notebook and team project) supported the program objectives and the majority reported that the program encouraged student participation and interest. We concluded that the E.G.G. program increased student content knowledge of the poultry industry and was a viewed as an implementable curriculum by teachers. </p> <p> Chapter Three shares the program’s procedures and results in relation to student situational interest during the program’s implementation. A pre-program questionnaire assessed student individual interest scores while post-module and post-program assessments evaluated student situational interest (n=111; 23.1% response rate). Increased individual interest scores (3.57± 0.10) may indicate a higher likelihood of having situational interest stimulated (scale: 1 to 5 with 1 having no interest and 5 having the highest level of individual interest). Results support that the online modules and the team project stimulated student situational interest because total situational interest scores, in addition to each individual subscale (i.e. attention, challenge, exploration, enjoyment, and novelty), were above a two on a four point Likert scale (scale: 1 to 4 with 1 having no situational interest during the activity and 4 having situational interest fully induced). <a>Previous validation of this assessment interprets subscale or total scores above a two to represent that students are experiencing situational interest during the activity in question. </a>Attention, challenge, novelty, and overall situational interest scores were significantly higher during the team project compared to the online modules (<i>p </i>< 0.01) while exploration and enjoyment subscales were similar. Student interest themes, coded from their notebook responses, showed interest in the modules’ learning objective topics with students demonstrating repeated interest in egg and hen anatomy and animal welfare. Overall, student situational interest was stimulated by the Elementary E.G.G. program, with overall interest highest during the team project compared with the online modules. Furthermore, students self-reported having interest in topics aligned with the modules’ learning objectives and inductive coding of responses found reappearing themes of interest relating to hen anatomy and animal welfare. </p> In conclusion, the results from the pilot Elementary E.G.G. program support that an integrated STEM and poultry science elementary curriculum has the potential to increase student agricultural literacy and can successfully impact student situational interest by engaging in purposefully developed activities. Further research is needed to adopt a framework across other poultry science sectors at a national level and improve accessibility of materials to a wider target audience. Additionally, improvements in program compliance may aid in increasing response rates of such research and are needed to increase transferability of findings.
88

Prophylactic strategies in the control of African horse sickness.

Simpkin, Tarryn Lyn. January 2008 (has links)
African horse sickness (AHS) is a non-contagious viral disease transmitted by an arthropod vector and is endemic to sub-Saharan Africa. The disease affects all equine species, but is more severe in horses and other equid species not native to Africa. Vaccination is the only demonstrated means of its prevention. The horse-owning public provides much anecdotal evidence of prophylactic strategies, such as repellents, stabling, alternate hosts, traps, paraffin, blankets, smoke or fans. The present study investigated the relationship of these strategies to the incidence of AHS, and evaluated alternate hosts, wind speed and repellents on the activity of males and females of the different Culicoides species.. Cypermethrin and citronella-containing repellents repelled the most female midges. Sheep and cattle offer an alternate blood meal to gravid and nulliparous female midges. Fans are very effective in keeping midges away from horses. Methods are summarised for the horse owner to implement in addition to vaccination to prevent AHS. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
89

A study of the Culcoides (Diptera: ceratopogonidae) vectors of African horse sickness to enhance current practical control measures and research methods.

17 January 2011 (has links)
African horse sickness virus causes a non-contagious, infectious disease of equids. It is epizootic to sub-Saharan Africa and parts of the Middle East. The epizootics caused by the virus have caused widespread devastation amongst equids worldwide. Fortunately no epizootic has lasted more than 5 years outside of sub- Saharan Africa. It is vectored by species of Culicoides midges (Diptera: Ceratopogonidae) and most importantly by the two Avarita species of C. imicola Keiffer and C. bolitinos Meiswinkel. The literature pertaining to the study and research of the virus, the disease and the vectors is reviewed. Models allowing prediction of future possible outbreaks as well as details of control strategies and findings of researchers are presented and discussed. The virus needs a long term reservoir host in which to overwinter and various theories are discussed. Control measures in South Africa are suggested so that outbreaks of the disease can be reduced. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermarizburg, 2008.
90

Effect of alternatives to antibiotic growth promoters on broiler performance.

Mosoeunyane, Nthoto V. January 2006 (has links)
No abstract available. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

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