Min utgångshypotes var att en minskad köttkonsumtion ger en minskad boskapsuppfödning. En boskapsuppfödning som idag tar i anspråk ca 70 procent av all jordbruksmark och 40 procent av den globala spannmålsproduktionen. Tanken var att en minskad boskapsuppfödning skulle bidra till en ökad tillgång på spannmål för människor och därmed en minskad svält. Men sambandet mellan svält och jordens resurser var inte så enkelt som jag hade förespeglat mig. Maktkoncentrationen som återfinns i matens distributionsled visade sig ha satt spelreglerna om tillgång och efterfrågan mer eller mindre ur spel. En ökad tillgång på mat genom en minskad köttkonsumtion och bättre resurshantering verkar därför inte påverka fattigdom och svält nämnvärt. Den nuvarande världshandeln visade sig också vara en bidragande orsak till fattigdom och svält då mat från nord, producerad med hjälp av statliga subventioner, konkurrerar ut lokalproducenter i syd. Den avgörande faktorn tycks vara människors tillgång på pengar. Inga pengar, ingen mat oavsett om maten finns i överflöd eller inte. Mina efterforskningar tyder på att de viktigaste faktorerna för att minska världssvälten är en förändring av den globala handeln för att därigenom öka de utsattas tillgång på kapital och självförsörjningsgrad samt en diskussion om vilket politiskt och ekonomiskt system som krävs för det.

Near infrared reflectance spectroscopy (NIRS) and geostatistical techniques were used to predict diet quality of sub-Saharan African (SSA) livestock, and to create cokriged estimated diet quality maps for cattle across a landscape. Rations of native vegetation were stall-fed to cattle (Bos indicus), sheep (Ovis aries), and goats (Capra hircus) to generate diet-fecal pair data. Trials were conducted in Ethiopia, Kenya, Uganda, Tanzania, and Ghana. Historical data from Ethiopia, Nigeria, and Niger were included. Diet samples were analyzed for crude protein (CP%), and digestible organic matter (DOM%), while feces were scanned for NIR spectra. NIRS equations were developed from data using modified partial least square (MPLS) regression. Coefficients of determination (R2) of CP for cattle, sheep, and goats were 0.92, 0.95, and 0.97, with corresponding standard errors of calibration (SEC) being 0.90, 0.79, and 0.80, respectively. Standard errors of cross validation (SECV) for CP were 1.12%, 1.08%, and 1.03% for cattle, sheep, and goats, respectively. R2 and SEC values for DOM were 0.88, 0.94, 0.94 and 2.82%, 1.68%, and 2.65%, for cattle, sheep, and goats, respectively. Corresponding SECV values for DOM were 3.26%, 2.07%, and 3.30%, respectively. The statistics reported were within the acceptable limits for NIRS calibrations. The results indicate that dietary CP and DOM of free-ranging SSA livestock can be predicted with the same precision as that of conventional wet chemistry methods. The cattle equation was used to predict cattle fecal samples collected, from February to August 2000, from selected households located within the northern Ghana savanna. The predicted CP% and DOM% were used with Normalized Differential Vegetation Index (NDVI) data, and cokriging technique to create diet quality maps for March and July 2000 for the northern Ghana savanna. Cross validation results indicated a moderate capability of cokriging to estimate predicted CP% for March (r2 = 0.687, SEp = 1.736) and July (r2 = 0.513, SEp = 1.558). Cokriged-estimated DOM value for July was above average (r2 = 0.584, SEp = 3.611), while March DOM% estimation was rather poor (r2 = 0.132, SEp = 3.891). The techniques of cokriging and creation of diet quality maps were moderately successful in this study.

In South Africa, communal land still plays a significant role in the lives of many rural communities. While these communal lands have ostensibly been included within municipal frameworks, decisions about their utilisation still remains a practical reality for many livestock keepers. This research examined current herding and grazing practices, grazing areas being used in summer and winter, and factors taken into consideration by livestock keepers and herders when choosing grazing areas in the communal sub-ward of Okhombe, in the northern Drakensberg, KwaZulu-Natal. The aim of this research was to investigate the socio-cultural reasons of livestock keepers behind decision making about grazing areas. The primary research question pursued in the study was: How do livestock keepers select areas for livestock grazing in the sub-ward? Three sub-questions were developed to guide the research: What grazing and herding strategies are currently being used? Which areas are used for grazing, and in which season(s)? What are the considerations for choosing areas for livestock grazing? Data were collected from fifty-one (51) cattle keeping households in the sub-ward. Data were collected in five steps. The first two steps involved household and in-depth interviews using interview guides. The latter three steps involved a transect walks, one case study and focus group discussions to test and verify the data. The findings showed a wide range of livestock kept in Enhlanokhombe sub-ward. The majority (61%) of cattle keeping households had cattle and goats, which are important for ceremonial purposes. The primary reasons for keeping livestock involved agricultural, food and cultural purposes. The herding strategies found in the sub-ward involved family/relative member, hired herders and no herder, with the majority using family/relative members as herders. Three areas were used for livestock grazing were Maqoqa, Skidi and Mdlankomo. The key finding showed an increase in supplementary feeding, a decrease in traditional remedy usage and safety from theft as a new factor taken into consideration when selecting grazing land. Other factors involved presence of cropping fields, availability of grass and water, distance from home and family traditions. From these findings, one can conclude that there are clearly tensions between culture and changes in the society, culture and changes in economy; and livestock keepers' heritage and modern lifestyle. These tensions make livestock keepers' decision making processes harder. The grazing and herding strategies, and the choices of communal grazing areas are influenced by these changes. As a result, livestock keepers are shifting from their heritage and culture to being economic and adapting to modern world. The heritage and the clarity of gender roles are breaking down. Grazing and herding are, therefore, no longer simple and familiar, but complex and unfamiliar to livestock keepers. These findings have serious implications for extension, advisory and development approaches used when addressing livestock management among traditional livestock keepers. They imply that what is needed is a multi-dimensional and inclusive view of the livestock keepers' practices. Rather than relying on the long-held assumptions about livestock keepers, serious attention must be given to the tensions in communal livestock keeping and the complexity of communal grazing strategies. These must be deliberately and consciously used to inform interventions designed to improve communal grazing management. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Arid and semi-arid regions have increasingly become the subject of much research and debate by scientists. By their very nature, these regions characteristically exhibit extremes which complicate the implementation of effective management strategies that ensure sustainable productivity and economic output. Namibia is one such region where low and highly variable rainfall conditions and fluctuating productivity pose a challenge to managers of commercial livestock enterprises, / who seek to optimise economic benefits while controlling the negative effect on herd production and income of unpredictable and unfavourable climatic events. Various management approaches are proposed as a means of exploiting periods of abundant productivity and so optimising income from herd production, while controlling for the effects of drought conditions. To analyse the effects of these various offtake strategies, a rainfall-driven plant-herbivore simulation model is used. The model comprises components simul~tihg vegetation and herbivore dynamics. The vegetation component incorporates soil moisture and nutrient allocation to plant parts. The herbivore dynamics sub-model comprises age and sex classes, population dynamics and animal energy requirements which govern accumulated fat reserves. The model is adapted to account for climatic and vegetation attributes specific to Namibia. An economic component including a seasonal monthly price structure is developed, and a dynamic feedback governing management decisions is incorporated. The much debated issue of whether to maintain a constant stocking rate or to track climatic variation by employing a variable stocking level is investigated, with the performance of management strategies incorporating these approaches ranked according to various factors, including annual returns, associated risk and annual stock mortality. The economic consequences of the timing of offtake are investigated, with the simulation of management strategies that implement destocking in the face of anticipated drought conditions. A dynamic projection of expected income allows the impact of forecasting potential economic gains on decision-making to be analysed. Results indicate that the performance of management strategies is not as dependent on climatic and seasonal price variability as was originally expected, with the application of a constant stocking level proving to be the most favourable strategy in terms of economic gain and variability of income. Tracking climatic variation by adapting stocking levels does not provide the improvement in economic returns from a livestock production system that was anticipated, although this approach is successful in effecting a significant reduction in annual stock mortality. Further results show the sensitivity of income to the long-term average stocking level characterising the management strategies investigated, as well as to the elasticity of the underlying price structure. The results of this study indicate that the implementation of management strategies designed to track climatic variation does not offer significant economic advantages over the application of a constant stocking approach. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Abstract available in the print copy. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Data collected between 1992/93 and 1996/97 from two long-term grazing trials were used to investigate the interaction between grazing animals and veld grass. In the first trial, the impacts of stocking rate and time of stocking in spring on both livestock performance and veld vigour (defined as the ability of a grass plant to regrow after defoliation) and condition were investigated. In the second trial comparisons were made, firstly between the impacts of sheep and cattle grazing, and secondly between various types and frequencies of rest, on veld vigour and condition. Treatments applied in the first trial comprised four stocking rates, namely 7, 10, 13 and 16 sheep ha¯¹ for the duration of the grazing season, and two times of stocking, namely as early as possible after spring burning and three weeks later. Sheep grazed each treatment continuously throughout the growing season. Treatments were applied to alternate blocks in a two-year cycle with each block resting for a year within a grazing cycle. Animal performance (mass gains over the season) was measured to quantify livestock performance. Herbage availability was measured on a species basis at intervals throughout each season using a dry-weight-rank procedure to determine grazing patterns. Residual effects of the grazing treatments on vigour were determined by measuring herbage regrowth on a species basis during the rest season which followed a season of grazing and comparing these measures to a previously ungrazed control treatment. Effects of the grazing treatment on proportional species composition were determined using a nearest plant point technique. Stocking rate had a non-linear effect on livestock performance, with livestock performance on the lightest stocking rate being less than on the two intermediate stocking rates. The mass gains on the heaviest stocking rate were generally the smallest. Delaying the time of stocking in spring resulted in smaller mass gains during the resultant shorter season. The sheep from both the early and late time of stocking groups had similar mean masses at the end of the season. The advantage of stocking early can thus be attributed more to saving the cost of alternative feed for the interim period than to additional mass gains due to stocking early. Quantification of livestock performance in terms of selected and available feed quality, quantity and species availability throughout each season was extremely complex due to multiple thresholds in the measured variables and no simple cause and effect relations could be established that would hold for spatial or temporal extrapolation. The negative impact of grazing on veld vigour was severe. Stocking rate and time of stocking had a secondary impact with the vigour loss positively related to increasing grazing pressure. The main factor influencing vigour loss was grazing, irrespective of time of stocking or stocking rate, as opposed to no grazing. The impact of grazing on vigour was severely negative in the palatable species, variable in the species of intermediate palatability and positive in the unpalatable species that were rarely, if ever, grazed. The stocking rate and time of stocking rate had an impact on the proportional species composition, with the more palatable species declining in proportion. There was an observable relation between impact of grazing on vigour and on species composition. Treatments applied in the second trial involved applying a full growing season rest in alternate years, half a growing season rest (late season) in alternate years and no rest to veld grazed by sheep or cattle at similar stocking rates. Residual effects of the treatments on veld vigour were determined by measuring species regrowth using a dry-weight-rank technique during the season following treatment application, and comparing it to controls ungrazed for one and two seasons respectively. Changes in proportional species composition were determined using a nearest plant point technique. The vigour of veld grazed by sheep declined rapidly relative to veld grazed by cattle. The vigour of palatable species was severely impacted, vigour of intermediate species was variably impacted and vigour of unpalatable species increased dramatically on veld grazed by sheep compared to the control treatments. Similar trends occurred in veld grazed by cattle, but to a lesser degree. Resting was beneficial for vigour recovery in both sheep and cattle treatments but it seems that the grazing treatment between rests has a greater influence on the veld vigour and condition than the rest itself. The veld grazed by sheep remained at a substantially lower productivity level than veld grazed by cattle. This was particularly evident in the change in productivity balance between palatable and unpalatable species in the sheep treatments, where palatable species vigour declined and unpalatable species vigour increased relative to veld grazing by cattle. Species composition of veld grazed by sheep deteriorated over the trial period in contrast to the veld grazed by cattle, which improved in species composition. Grazing management recommendations for sourveld should include a bias towards cattle, optimising stocking rate for improved performance and resting for enhancing vigour of the palatable grasses. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1999.

Considerable understanding of the functioning of semi-arid systems is still needed to enable range managers to formulate management policies, with a degree of confidence. Long term data sets that encompass a wide range of interactions between the various major components of a semi-arid system (vegetation, herbivory, animal performance, landscape and rainfall), are unfortunately rare but essential to provide sufficient depth of data to adequately test various hypotheses about rangeland dynamics. This study comprises an analysis of a ten year data set derived from two cattle stocking rate trials in the semi-arid savanna of KwaZulu/Natal. Statistical analysis revealed that the most pronounced and rapid compositional change was due to rainfall, but that stocking rates between 0.156 and 0.313 AU ha ¯¹ had an important effect as well. Sites on steeper slopes with heavy stocking rates, exhibited the greatest amount of compositional change between 1986 and 1996 (40 Euclidean points in heavy stocking rate treatments on slopes vs 21-24 Euclidean points in heavy stocking rate treatments on flatter land, or 11-24 Euclidean points in low stocking rate treatments). Heavy stocking rates in conjunction with low rainfall tended to cause decreases in densely tufted perennial grasses and increases in annuals and weakly tufted perennials. Multiple regression analysis revealed that seasonal peak grass production (measured as disc height) declined between 1986 and 1996 only at those sites on steeper slopes with heavy stocking rates. The camps that declined in productivity also underwent the greatest degree of compositional change. The decline in grass productivity in certain high stocking rate camps did not translate into a decline in cattle performance. Depending on rainfall, cattle gained on a seasonal basis between 112 and 241 kg at low stocking rates, 82 and 225 kg at medium stocking rates and 84 and 217 kg at high stocking rates Rainfall, compared with stocking rate, accounted for the greatest amount of variance in seasonal peak grass production and cattle performance. Cattle performance had a strong curvilinear response to rainfall, which also proved to be a better predictor of cattle performance than grass biomass. There were no clear trends in soil physical and chemical characteristics between low and high stocking rates that could provide convincing evidence that loss of soil nutrients was an important mechanism of range degradation. The total standing crop of plant nitrogen but not of phosphorus tended to decline at high stocking rates. Plant nutrient and van Soest analyses suggested that forage quality was higher at heavy stocking rates. The results of this study generally supported traditional concepts of rangeland dynamics with regard to rainfall and grazing effects on compositional change and seasonal grass production. The results were important in being able to show quantitatively that heavy stocking rates result in a decline in grass production and that this effect is dependent on an interaction between stocking rate and landscape position or slope, and that there is a link between a decline in seasonal grass production and compositional change. The results also highlighted areas for future research that would be useful for furthering our understanding of various aspects of rangeland dynamics and mechanisms of degradation. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 5 uppsatser.

Thesis--Universität Bielefeld, 1997. / Includes bibliographical references (p. [511]-530).

Made available in DSpace on 2014-06-11T19:23:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-25Bitstream added on 2014-06-13T19:29:31Z : No. of bitstreams: 1 silva_ja_me_sjrp.pdf: 532607 bytes, checksum: fa6463333af7dc34ef59d3dc24603f96 (MD5) / O presente trabalho teve como objetivo avaliar as características do javaporco (Sus scrofa javaporco) por meio dos parâmetros zootécnicos e tecnológicos. Os dados zootécnicos foram medidos pela avaliação do consumo de ração, do ganho de peso e da conversão alimentar desse animal. Quanto aos aspectos nutricionais, foram realizadas análises da composição centesimal básica (umidade, proteínas, lipídeos, cinzas e carboidratos) e análises quanto à presença/ausência de Salmonella sp.. Para tais estudos, os animais foram divididos em quatro lotes, cada um contendo três indivíduos, machos e castrados, abatidos na idade de 4 (Lote A), 6 (Lote B), 8 (Lote C) e 10 (Lote D) meses. Em relação ao ensaio de crescimento, os javaporcos apresentaram peso vivo no abate variando entre 14, 50 kg a 57,66 kg em 300 dias de avaliação. Os lotes B e C, foram os que apresentaram melhores valores de conversão alimentar correspondendo a 3,49 e 3,72, respectivamente. Os rendimentos das carcaças variaram entre 54,75 a 75,15%, com uma média de produção de carne em relação ao peso da carcaça de 33,13% para todos os animais. Quanto à composição química básica o percentual de umidade para os lotes A, B e C variou de 73,90 a 74,23%, já o lote D apresentou valor inferior a este, 70, 96%. Os valores de proteínas variaram de 17,35 a 18,33% em todos os lotes. O percentual lipídico apresentou valores médios de 3,31 a 4,34% e os mineiras oscilaram entre 1,17 a 1,84%. No estudo da estabilidade microbiológica, em relação à presença/ausência de Salmonellas sp. somente o lote A encontrou em não conformidade com a legislação, tendo 2 amostras contaminadas. Diante destas observações, a adoção de estudos quanto ao manejo mais adequado e uma alimentação balanceada e especifica para esses animais tornam-se necessárias para que os interessados tenham sucesso na criação deste animal... / The present research was focused in the evaluation of the characteristics of the javaporco (Sus scrofa javaporco) by means of zootechnical and technological parameters. The zootechnical data had been provided by the evaluation of the consumption of ration, the gain of body weight and the feed conversion of this animal. Regarding the nutritional aspects, analyses of basic proximate composition was carried out (humidity, proteins, lipids, leached ashes and carbohydrate) and analysis for the presence/absence of Salmonella sp was performed as an indicative of microbial contamination. For such studies, the animals were divided into four lots, each of them containing three male animals which were slaughter at the age of 4 months (Lot A), 6 months (Lot B), 8 months (Lot C) and 10 months (Lot D). Regarding the growth trial, the javaporcos presented a live weight, before slaughtering, between 14,50 kg to 57,66 kg in 300 days of evaluation. Lots B and C, were the ones that presented better values of feed conversion, 3,49 and 3,72, respectively. The carcasses yield varied between 54,75% to 75.15%, with an average productivity of meat in relation to the carcass weight of 33,13% for all animals evaluated. Regarding to the basic chemical composition of the meat, the percentage of humidity for lots A, B and C varied from 73.90% to 74.23% although Lot D presented a lower value of 70, 96%, however the protein values varied from 17.35% to 18.33% in all lots. The percentage lipid values were on average 3.31% to 4.34% and the minerals varied from 1.17% to 1.84%. In the study of microbiological stability in relation to the presence/absence of Salmonella sp. the lot A was the only that met in disagreement with the legislation, having two contaminated samples. Having said that an appropriate studies and a balanced and vii 20 specific diet for these animals become necessary for parties interested in order... (Complete abstract click electronic access below)