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The purpose of this research is to support the California Department of Food & Agriculture (CDFA) with education and outreach about recent changes regarding antimicrobial use in livestock, and to enhance their emergency communications network. This was done by characterizing a population of small-scale livestock owners underserved with regards to educational outreach about animal health issues, such as antimicrobial use rules. The project also seeks to enhance public understanding of the importance of responsible antimicrobial use in animal and human health. To accomplish this, the study used a survey administered in person at local farm supply stores and online to investigate the level of understanding of antimicrobial rules among livestock owners in San Luis Obispo county. The survey gathered information about the livestock owners’ practices, connection to livestock groups, and access to information pertaining to animal health among other things. The results of the survey showed that respondents were largely unaware of new rules pertaining to use of antimicrobials in livestock. Familiarity with California rules of this kind was used as an indicator of access to information about animal health and was found to correlate positively with knowledge about antimicrobial resistance and familiarity with federal rules concerning antimicrobial use in livestock. As predicted, respondents with a connection to 4-H and FFA had greater familiarity with both federal and state rules concerning antimicrobial use in livestock.

Drought is a water related natural hazard. It is difficult to characterize drought because of its diffused nature and spatiotemporal variability. However, understanding the variability of drought characteristics such as severity, frequency, duration, and spatial extent is critical in drought mitigation and planning. Impact of drought on agriculture, water supply, and energy sectors has been long-recognized. The current understanding of drought and its impact is limited due to its complex characteristics and ways in which it impacts various sectors. This study focuses on two important aspects of drought: variability of drought characteristics across different spatial scales, and impact of droughts on crop yield and groundwater. Two drought indices, one integrating severity and spatial coverage, and also taking into account the type of specific crops, were investigated for county level use. The developed indices were used in studying drought at the county level, and its impact on crop yields. These indices can be used for resource allocation at the county level for drought management. Drought is reported in the United States (U.S.) for different administrative units at different spatial scales. The variation of drought characteristics across different spatial scales and scale dependence was investigated, demonstrating the importance of considering spatial scales in drought management. A methodology is proposed to quantify the uncertainty in reported values of drought indices using geostatistical tools. The uncertainty was found to increase with increasing spatial scale size. Artificial Neural Network and regression methods were used to model the impact of drought on crop yield and groundwater resources. Relationships of crop yields and groundwater levels with drought indices were obtained. Overall, this study contributes towards understanding of the spatial variation of drought characteristics across different spatial scales, and the impact of drought on crop yields and groundwater levels. / North Dakota Water Recourses Research Institute (ND WRRI) Fellowship Program / North Dakota State University Graduate School Doctoral Dissertation Award

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Magister Artium - MA / The Cederberg is increasingly associated with wildlife and ecotourism. Long-established rural communities practising subsistence farming reside in the Cederberg, some on the very boundary of the Cederberg Wilderness Area. Land uses related to tourism and conservation are currently reframing the Cederberg as a leisure landscape; a development that is not always compatible with sustaining the livelihoods of local inhabitants. Humans often occupy spaces to create a ‘civilised’ place of belonging for themselves and their domestic animals, and may regard certain indigenous wildlife species (such as baboons and leopards) as intrusive vermin. Livestock-keeping communities in the Cederberg are affected in particular by leopard conservation efforts. Livestock (sheep and donkeys in particular) is important to these farmers but often in danger of becoming prey to wild predators. In the Cederberg, the endangered Cape Mountain Leopard moves freely between the protected and inhabited spaces and often comes into contact with livestock owned by local subsistence farmers. This dissertation is rooted in the emerging sub-discipline of ‘animal geographies’. It explores divergent views of the term ‘wilderness’ as well as the treatment of ‘wild’ animals within the areas occupied by local people. It focusses on the community involvement in conservation practices and human-wildlife conflict issues, exploring community responses to their changing context and especially current conservation practices of CapeNature and the Cape Leopard Trust (the provincial conservation authority and an NGO respectively). Interviews with local people about current and historical leopard encounters are drawn upon in the analysis. The study is concerned to understand how conservation is impacting on local communities, and their responses to these shifts. Results suggest that there is substantial gap in the relationship with the communities and conservation authorities, especially regarding leopard conservation and livestock preservation. The communities of Wupperthal continue to suffer significant losses due to leopard predation. As it is now illegal to trap or kill leopards, residents have few strategies to protect their livestock. While some communities have a better relationship with CapeNature regarding the tourism activities within their community and other conservation initiatives, their considerable frustration was evident. The study explores the complex land issues in the region, and suggests possibilities for improvement in the relationship between local subsistence farmers and conservation authorities.

Gousiekte (“quick” disease) is a plant-induced cardiomyopathy of livestock in South Africa, that is characterized by the sudden death of animals within a period of 3-6 weeks after the initial ingestion of toxic plant material. Six species of three genera of the Rubiaceae family viz. Pachystigma pygmaeum, P. thamnus, and P. latifolium; Pavetta harborii and P. schuman-niana, and Fadogia homblei have been identified as the causative agents of the disease. The toxin responsible for the poisoning, named pavettamine, has been isolated and the structure and absolute configuration established as (2S,4R,8R,10S)-1,11-diamino-6-aza-undecane-2,4,8,10-tetraol, or the enantiomer, by mass spectrometry and NMR spectroscopy. Retrosynthetic analysis of the pavettamine molecule as outlined in the dissertation showed that the secondary amine function could be obtained from the amide functional group in an intermediate such as (2R,4S)-N-[(2′R,4′S)-2,4,5-trihydroxypentan-1′-yl]-2,4,5-trihydroxy-pentanamide A. Disconnection of the amide bond then generated two C5 building blocks viz. an amine B and a carboxylic acid C which through a set of functional group transformations led to a common C5 building block, a pentane-1,2,4,5-tetraol D. The terminal primary hydroxy groups required different protecting groups at all times in order to safe-guard the integrity of the two stereogenic centres. In addition identical protecting groups but different to those used for the primary hydroxy groups, were necessary for the secondary hydroxy groups. Further analysis of the C5 building block D showed that it could be obtained from (2S)-malic acid by functional group transformations, chiral sulfoxide methodology and an appropriate protective group strategy. A suitable protective group strategy was developed and an 11 step synthetic route for the C5 building block established. The successful conversion of this moiety through functional group transformations provided the C5 amine B and C5 carboxylic acid C which were linked to give the target compound, the amide D but with the hydroxy groups protected. The synthetic study presented in the dissertation provides an efficient methodology toward the synthesis of any of the 10 possible stereoisomers of pavettamine. / Dissertation (MSc)--University of Pretoria, 2009. / Chemistry / unrestricted

Sustainable animal production on pasture planted on rehabilitated mine land will only be possible if the optimal stocking rate for animal and pasture production is determined. A grazing trial was conducted on tall fescue, established on rehabilitated mine land and irrigated with mine waste water. The aims of this study were to quantify: a) animal performance and nutritive value at different levels of nitrogen (N) fertilization during pasture establishment, and b) intake, animal performance (defined as average daily gain; ADG) and nutritive value when different stocking rates were applied. This study was done during two seasons: season one in winter (6 June -16 July 2008) and season two in spring (28 Aug – 6 Nov 2008). In terms of post mining land use this study supplied valuable information on potential livestock production. The higher level of N fertilization applied during the winter of 2007 at pasture establishment resulted in a significantly (P < 0.05) higher crude protein (CP) concentration a year later compared to the lower levels of N fertilization. During the winter grazing season the pasture contained an average of 83.4 g CP kg-1 dry matter (DM), 601.9 g NDF kg-1 DM, 6.2 g Ca kg-1 DM and 1.7 g P kg-1 DM, the average in vitro organic matter digestibility (IVOMD) was 642.2 g kg-1 OM and the average leaf: stem ratio was 88:12. The ADG of crossbred weaner calves grazing the low N fertilization (LN), low stocking rate (LS) paddock (229.1 g day-1) was significantly (P < 0.05) lower than the ADG of weaner calves grazing the LN, high stocking rate (HS) and the high N (HN), LS respectively. The ADG of the animals in the HN, LS paddock was 482.7 g day-1 and in the LN, HS paddock was 310.6 g day-1. The low ADG for the LS treatment was due to the low CP concentration of this paddock, with values as low as 55.1 g CP kg-1 DM recorded during the winter grazing period. Low pasture nutritive value during winter can potentially limit animal production.spring grazing season the pasture contained an average of 101.0 g CP kg-1 DM, 639.1 g NDF kg-1 DM, 8.9 g Ca kg-1 DM and 2.1 g P kg-1 DM. The average leaf: stem ratio was 85:15, IVOMD was 717.5 g kg-1 OM and effective DM degradability (in situ) was 56.1 %. The average OM digestibility estimated with the alkane method varied between 720.8 to 768.3 g kg-1 depending on the alkane used and weather a correction was made for the faecal recovery of the alkane used. On average the forage available in the paddock with the LS had a significantly (P < 0.05) higher CP concentration, leaf: stem ratio and IVOMD, with a significantly (P < 0.05) lower NDF concentration than the HS paddock. This is probably due to the fact that in the HS paddock forage with a high nutritive value was removed at a higher rate. Irrespective of the calculation used, digestibility calculated by the alkane method did not differ significantly (P > 0.05) between paddocks at any time period. The average intake in the paddock with medium grazing stocking rate (MS) was significantly (P < 0.05) higher than the average for the other paddocks. The paddock with the MS was managed to supply a pasture DM allowance of 2.5 % body weight (BW). The DM intake over the spring season was 2.2 % BW. The MS treatment supplied sufficient plant material without resulting in large accumulation of plant material. The ADG for the spring season was 110.5 g day-1 and averages for each paddock did not differ significantly (P > 0.05) from each other. During the / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Animal and Wildlife Sciences / unrestricted

Poisonous plants are one of the most important causes of economic losses in the livestock industry throughout the world, especially in those areas where rangeland and pasture grazing are practiced. In the livestock industry in South Africa, total annual costs of plant and fungal poisoning (mycotoxicosis) are conservatively estimated to be R104 506 077, 8% of which is due to D. cymosum poisoning. There is no antidote for D. cymosum poisoning of livestock and wide scale eradication by conventional control methods are labour intensive, expensive and often impractical. In South Africa, the communal or emerging farming sectors are the most affected. This is mainly due to the high costs associated with control measures such as fencing, supplementary feeding and veterinary expenses, and / or lack of grazing management with livestock numbers exceeding the biological carrying capacity of the rangeland due to lack of grazing lands. Proper rangeland management is the surest and most economical means of reducing plant poisoning of livestock. Focused research on the ecology of these poisonous plants in rangeland communities to improve rangeland management would assist in the development of these strategies. This study investigated D. cymosum infested savanna communities, focusing on understanding how negative (inter- and intraspecific competition) interactions influence community structure, dynamics and productivity and how plants in D. cymosum communities avoid these negative interactions by investigating their seasonal phenological patterns. Dichapetalum cymosum coexists with trees, such as Burkea africana, Ochna pulchra and Terminalia serecia, as well as shrubs species, such as Pygmaeothamnus zeyheri and Perinari capensis, in well drained, nutrient poor soils. Some plant ecologists contend that in an environment where water is limited, competition is inevitable amongst plants occupying the same above-ground stratum and the same soil horizon. Others contend that plants avoid competition with each other by sharing resources spatially and temporarily. Field experiments were conducted to investigate how the above species interact and coexist with each other in two South African savanna communities. Fourteen (100 m x 100 m) D. cymosum infested sites were identified in each community. Disperal analysis using nearest neighbour distance was used to investigate competition among species, and above ground flowering phenology along niche axes to determine temporal and spatial sharing of resources. The dispersal analysis revealed aggregated populations among species when intraspecific and combined (all individuals independent of species) analyses were conducted. However, in all instances, aggregation among species was not significant. No interspecific competition was observed among species when correlation analysis was performed between nearest neighbour distance and combined canopy cover of the nearest neighbour pair. Intraspecific competition was, however, observed for tree species T. sericea (n = 128; r = 0.3952; P < 0.0001) and B. africana (n = 166; r = 0.49926; P <0.0001) and a shrub species, D. cymosum (n = 391; r = 0.39788; P <0.0001). Segregation was found between O. pulchra and both B. africana (S = 0.999, χ² = 102.7588, P <0.0001) and T. sericea (S = 0.999, χ² = 57.8571, P <0.0001). Shrub species were also segregated, all with interspecific nearest neighbour pairs occurring less often than expected. The vegetative phenology of all experimental plant species followed the rainfall gradient. Differences in reproductive phenologies were observed between O. pulchra and both B. africana and T. sericea. Dichapetalum cymosum also differed from P. capensis and P. zeyheri in their reproductive phenologies. The differences in the reproductive strategies of at least one of the species in each growth form account for the observed spatial distribution amongst species in these communities. The observed growth patterns shown by the vegetative phenologies, however, suggest that lengthy retention of nutrients is a strategy to avoid competition for nutrient uptake with other species in these communities. Segregation between species and positive correlation iii between nearest neighbour distance and combined canopy cover of the nearest neighbour pairs suggest that intraspecific competition and interspecific facilitation determine D. cymosum woody plant community structure. This study had limited application to rangeland management. However, it can be concluded that grazing of D. cymosum communities should take place during mid-summer, when enough grazing material is available to allow animals to vary their diet. The introduction of animals in poor condition or naïve animals into these lands should be avoided in winter and spring as they will graze non-selectively resulting in D. cymosum poisoning. To utilize these areas as grazing lands, supplements need to be provided to assist in the detoxifications of toxins once ingested. / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Plant Production and Soil Science / unrestricted

An zwei sächsischen Rinderanlagen in Waldnähe wurde zwei Jahre lang der Einfluss der Ammoniakemission auf die räumliche und zeitliche Dynamik der Stickstoffbelastung im Umfeld der Betriebe durch Messung von Immission, Deposition und Transmissionsbedingungen untersucht. Zur Anwendung kam eine neue Methode, die auf Basis kontinuierlicher Messungen von Ammoniakimmissionen und meteorologischen Parametern die Rückrechnung auf anlagenbezogene Emissionen ermöglicht. Dabei wurden zwei Messverfahren bewertet: DOAS-Trasse und Passivsammler. Alle Messpunkte im Umfeld der Betriebe zeigten einen deutlich erhöhten Ammoniumanteil am anorganischen Stickstoffeintrag. An den Referenzpunkten im Freiland wurden ca. 15 kg/(ha a) höhere Stickstoffdepositionen als an den Dauerbeobachtungsflächen des ländlichen Hintergrunds ermittelt. Die Stickstoffgesamtdeposition lag an allen Messpunkten deutlich über den für Nadelwald definierten empirischen Critical Loads. Dennoch sind die Wälder bisher nicht geschädigt.

Philosophiae Doctor - PhD / The lack of bioclimatically suitable forage species for livestock production in the water-limited agro-ecological areas of South Africa has resulted in significant feed shortages within these areas during the ongoing drought experienced within the country. This, in turn, has resulted in significant livestock mortalities leading to financial difficulties for the farmers and farming communities within these areas. Thus, many of the water-limited agro-ecological areas in South Africa have been declared disaster areas. These cyclic long-term droughts, as well as more common short-term droughts are expected to increase in frequency, duration and intensity under the predicted future bioclimatic conditions. Although there has been significant investment into the development of improved, better-adapted forage crops for these bioclimatically marginal agro-ecosystems, these efforts, to date, have largely been unsuccessful. Therefore, in this study, we propose to identify and evaluate species that are native to the water-limited South African agro-ecosystems and that can potentially be implemented in alternative fodder flow programs within these water-limited agro-ecological areas. / 2022