Vegetation monitoring, recording the recovery or change in plant cover over time, for several Karoo shrubs was undertaken to evaluate the Savory Grazing System on a farm in the Succulent Karoo. This evaluation was quantified by establishing if the proposed 120- day rest period between grazing events was sufficiently long enough for complete recovery of the vegetation. Complete recovery was described as sufficient regrowth after a grazing event so that continual cover loss would not result over time. Optimum resting periods would ensure that cover loss, due to grazing, could be recovered so that plant size and reproductive potential was not detrimentally affected. The ellipse intercept method was used to sample piospheres (or zones of attenuating animal impact) around water points in two vegetation types. From these results, 320 line transects for vegetation monitoring were located between 140 and 180m from the water points. One and a half year old piospheres of one farm were compared to seventeen year old piospheres on another farm with similar vegetation composition. The piospheres on the younger farm were expanding at an approximate linear rate of 80m per year, however, this rate slows considerably, as was found on the farm with older piospheres. Stability or equilibrium appears to be reached at approximately 320m from the water point in the older system. The line transects were used to record the change in cover of palatable and unpalatable Karoo shrubs on a monthly basis over an 18 month period. In all instances it was concluded that the proposed 120-day rest period was not sufficiently long enough for complete recovery of the vegetation. The highly palatable species, especially Osteospermum sinuatum and Tetragonia spp., were the most heavily utilized and detrimentally affected. Larger individuals of the palatable shrubs O. sinuatum and Tetragonia spp. were more severely grazed than smaller individuals as a result of smaller individuals utilising spiny nurse plants under which to establish. If the present rest period is continued the result could be overgrazing and local extinction of these important fodder species. The responses of two highly palatable species, O. sinuatum and Tetragonia spp., were monitored closely in relation to rainfall and grazing events. Grazed and ungrazed (protected) individuals were monitored over one year to substantiate the results obtained from the line transects. The rest period was again found to be too short for full recovery and was also found to be reducing the reproductive output of O. sinuatum and Tetragonia spp.. The recruitment of O. sinuatum and Tetragonia spp. was also measured by comparing seedling establishment in grazed, ungrazed (vegetation protected from sheep grazing) and cleared vegetation. In an attempt to rehabilitate these rangelands, Pteronia pallens, a dominant unpalatable shrub, was cleared and the resultant seedling recruitment of O. sinuatum and Tetragonia spp. monitored and compared to grazed and ungrazed vegetation. Juvenile recruitment of these species was found to be significantly lower in the grazed than in the ungrazed vegetation. Recruitment of Tetragonia spp. was found to be significantly higher in the cleared strip compared to the grazed and ungrazed vegetation. The results obtained in this study suggest that the present grazing regime is having a detrimental effect on the vegetation and that revised management procedures are needed to ensure the conservation of these rangelands. The rest periods between grazing events need to be lengthened as well as a reduction in stock numbers. Certain camps need to be skipped on a seasonal basis during the flowering season in order to increase the reproductive output of highly palatable species. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1983.

Patch grazing may be an important factor providing the focus from which wide-scale veld degradation has occurred in the humid grasslands of KwaZulu-Natal. A number of discrete studies were therefore initiated to examine the patch grazing patterns and selected factors which may influence patch grazing at two sites in the humid grasslands of KwaZulu-Natal. The sites were located at Ukulinga Research Farm, situated in the Southern Tall Grassveld, and Kokstad Research Station in the Highland Sourveld. An investigation into the frequency and intensity of gazing patches and non-patches at Ukulinga Research Farm indicated that patch grazing was most evident and most extensive during summer and autumn. As forage in the patches became limiting during winter animals were forced to forage in areas not frequently grazed during the season. The patch grazing pattern was further modified by the time of grazing commencement after a burn in early spring. Early grazing significantly reduced the extent of patch grazing. With early stocking animals were forced to graze less selectively while with increased delay in the commencement of grazing, animals became increasingly patch-selective. Early grazing in conjunction with an autumn rest and heavy grazing during winter could significantly reduce patch grazing. Urine and dung significantly influenced the patch grazing pattern. The sward surrounding a urine deposit was preferentially grazed by both cattle and sheep for a period of at least six months after deposition. Cattle rejected the sward surrounding cattle and sheep dung immediately after deposition and for a period of up to six months. Sheep also rejected cattle and sheep dung patches immediately after deposition. As dung deposits aged, sheep tended to increase their grazing around both cattle and sheep dung pats, and after six months dung did not seem to influence sheep grazing. Urine may be an important factor influencing patch initiation and consequent patch development. A study to examine the characteristics of patches and non-patches in the Highland Sourveld revealed that patches were characterised by lower soil moisture, soil depth and hydraulic conductivity, but by a higher soil nutrient status. Patches and non-patches could also be distinguished in terms of species composition and basal cover. Patches were characterised by Increaser II species, especially Microchloa caffra and, non-patches by Increaser I species such as Trachypogon spicatus, Alioteropsis semialata and Eulalia villosa. Three seasons of patch grazing at Kokstad Research Station negatively influenced the vigour of Themeda triandra in patches relative to the non-patches. The vigour of T. triandra in patches was consistently low throughout a full season's rest. The vigour of T. triandra in non-patches was initially significantly higher than the vigour in the patches and remained so for c. 24 weeks. Vigour measurements at the start of the following season showed that photosynthate accumulation had taken place and a full seasons rest proved to be sufficient in restoring the vigour of T. triandra in patches to the same level as that in non-patches. A full seasons rest did, however, not prevent animals from regrazing the same previously grazed patches the following season. Growth in patches also started c. six weeks later than in nonpatches and above-ground herbage production in patches was significantly lower than nonpatches for at least 20 weeks after a bum. At the end of a full season's rest above-ground herbage production in patches was still slightly lower than that in non-patches possibly due to a difference in species composition between patches and non-patches. Some implications of patch grazing are discussed together with an evaluation of some management recommendations for the humid grasslands with the aim of reducing the potential for patch degradation. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.

This study was designed to provide the means for implementing formal scientific vegetation management 1n the succulent valley bushveld of the eastern Cape, South Africa. Nowhere in the world has a detailed, effective and practical veld management system being developed entirely from research, and even the most successful management systems rely heavily on the intuition of people. A process, formally called 'adaptive management', combines this intuition with scientific testing and the overall objective of this study was to provide a framework for formalized adaptive management in succulent valley bushveld. On analyzing the process of adaptive management, the following knowledge 'tools' were identified: (i) a management system for immediate implementation; (ii) a technique for vegetation assessment; (iii) a technique for monitoring vegetation change; (iv) a technique for monitoring forage use and recovery; (v) a list of key forage species; (vi) a model to set initial stocking rates; (vii) a method of recording essential information; and (viii) a database of ecological principles. Providing these 'tools' became the goals of this study. These topics covered almost all facets of rangeland science, and the approach was to address these in a 'top down' manner, rather than sub-optimize by specializing on anyone component. Most of the 'tools' were achieved to a greater or lesser extent and are presented as a series of publications. However, a central tool, that for monitoring vegetation change, remains outstanding despite comprehensive testing of a range of traditional botanical methods. Indeed, critical review revealed that this 'missing tool' is a problem which is common in all vegetation communities in South Africa - despite the impression created by vegetation researchers that adequate techniques are indeed available. This is serious because land managers are not able to evaluate the impact of their efforts and the government is unable to monitor the effectiveness of their research and extension services, costing millions of public monies annually. The implication also, is that vegetation cannot be managed scientifically (management implies monitoring). Either formal adaptive management is not practicable, or researchers are operating from an inappropriate paradigm; specifically that of providing techniques for their research projects and claiming that these (or derivatives of these) are adequate for farm or regional scale monitoring. More generally, research has often become an end in it's self, with research quality being judged by criteria which are of little significance to the real world and which damage efficiency. Perhaps, the real value of vegetation research lies in the experiential learning which the researcher gains not the inevitably parochial results. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1993.

Bush encroachment is a major problem for the savannas supporting livestock in the Eastern Cape. Farmers employ chemical poisoning and mechanical clearing of woody vegetation to improve grass production. This thesis addressed the following questions. 1. Does soil fertility and hence, herbaceous production and/or quality increase beneath or between former bushclumps following woody clearing or poisoning? 2. Are chemical or mechanical control methods effective for all woody species? 3. Does bush density and height decline with increasing competition from the herbaceous layer? 4. Can fire and goats retard or revert woody re-establishment, thereby keeping these savannas open? A trial for assessing different methods of controlling bush was conducted near Kei Road. Initial treatments included chemical poisoning, mechanical clearing and a control, each replicated eight times in 0.36 hectare plots. Follow-up treatments were control, fire, goats, and the combination of fire and goats each replicated twice per primary treatment. Two additional mechanically cleared plots were oversown with Chloris gayana seeds. Herbaceous production, species composition, foliage quality and soil fertility, and mortality, recruitment, height increase and density of woody individuals were monitored for five seasons. Mechanical clearing of the woody vegetation increased soil fertility, except total nitrogen, and that explained the dramatic response in grass production that endured for the first four seasons since clearing. The periphery and ex-bushclump zones were characterised by increased colonization of Panicum maximum while there were no changes in frequencies of other key herbaceous species in all vegetation zones. Acacia karroo and woody "weeds" (Solanum incanum, Berkheya bipinnatifida) established from seed while all other woody species recruited mainly from coppicing. Seedling recruitment and resprouting resulted in high densities of woody stems and individuals by the second season after clearing when compared with the pre-clearing levels. Oversowing cleared areas with pasture grasses did not only increase grass production but also reduced the density of coppicing woody plants and "weeds". Chemical treatments mirrored the controls in terms of grass production, except during a very wet season, and species composition. Although encroaching woody species (e.g. Scutia myrtina, Maytenus heterophylla and Trimeria trinervus) were susceptible to poisoning, woody plant density was not reduced. Multi-stemmed woody individuals were resistant to poisoning. Fire and goats kept most coppicing woody plants short, less than half a metre, after three seasons of browsing and also improved grass production in the dense bushclumps suggesting that these clumps were being opened up. However, high browsing pressure forced goats to graze more hence this effect was masked. This study indicates that chemical and mechanical control of bush are economically unsustainable for beef and mutton production, at least in the medium term. Fire and goats are appropriate as a follow-up strategy for retarding woody regrowth, keeping bushclumps open, improving grass production and economic viability of mechanical clearing. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.

Thesis (M.S. - Renewable Natural Resources)--University of Arizona. / Includes bibliographical references.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 300-330). Also available via the Internet.

A intensidade de pastejo modifica as características estruturais do pasto, afetando assim a produção de forragem e animal. O sucesso na utilização de cada espécie passa pela compreensão dos mecanismos morfofisiológicos e de sua interação com o ambiente e o manejo. O objetivo do presente trabalho foi o estudo da dinâmica de produção de pastos de papuã submetida a diferentes intensidades de pastejo, obtidas através de quatro alturas do dossel forrageiro (10, 20, 30 e 40 cm). As unidades experimentais foram distribuídas em um delineamento em blocos completamente casualizados, com três repetições. Para controlar a altura do pasto, foram utilizados caprinos meio sangue Boer, com 15 meses de idade e peso médio de 38 ± 5,3 kg PV, em regime de lotação contínua e taxa de lotação variável. A cada 21 dias, foram avaliadas características agronômicas: relação folha/colmo, massa e produção de forragem, carga animal e o valor nutritivo da dieta dos animais. A morfogênese, bem como a dinâmica de crescimento, consumo e senescência do pasto, foi obtida pela avaliação de 30 perfilhos marcados em cada unidade experimental. Tal avaliação foi feita a cada dois dias em dois períodos: no início e no fim do experimento. Cada período contou com cinco avaliações. A maior taxa de acúmulo diário foi obtida em 33,7 cm (137 kg MS/ha/dia) e a produção total de forragem foi maior em 34,2 cm (12.538 kg MS/ha). A carga animal diminuiu com o aumento da altura do pasto. A densidade populacional de perfilhos diminuiu linearmente com o aumento da altura do pasto. O filocrono aumentou linearmente com o aumento da altura do pasto, bem como o tamanho das folhas e a longevidade das mesmas. A frequência de desfolha foi maior nas folhas em crescimento do que nas expandidas. A eficiência de utilização diminui com o incremento da altura do pasto de modo mais pronunciado no final do ciclo de desenvolvimento. Em pastos mantidos em maior altura os animais podem maximizar o consumo de forragem, podendo selecionar maior quantidade de folhas. A massa e a oferta de forragem aumentaram com a altura, proporcionando incremento no desempenho dos animais (57 g PV/dia) e, consequentemente, maior ganho por área (262 kg PV/ha), na menor intensidade de pastejo. / Grazing intensity affects sward canopy traits affecting forage and animal production. The successful use of each species depends on understanding of morphophysiological mechanisms of grasses and their interaction with the environment and management. This study aimed to study the alexandergrass pasture dynamics of production subjected to different grazing intensities obtained from four sward canopy heights (10, 20, 30 and 40 cm). The experiment units were laid out as random blocks design with three replications. Were used crossbred boer goats, fifteen months-old and weighting 38± 5,3 kg under continuous stocking and variable stocking rate. Every 21 days were evaluated: leaf/stem ratio, herbage mass, forage production, stocking rate and diet nutritive value. Morphogenesis as well as growth dynamics, dry matter consumption and senescence was obtained by evaluating 30 marked tillers in each experimental unit every two days in two periods: at the beginning and end of the experiment period. Each period had five assessments. The highest dry matter accumulation rate was obtained with 33.7 cm (137 kg DM/ha/day) and total forage yield was higher at 34.2 cm (12,538 kg DM/ha). Stocking rate decreased as the pasture sward canopy height increased. Tiller population density decreased linearly as the sward canopy height increased. Phyllochron increased linearly as the sward canopy height increased, as well as size and longevity leaves. Defoliation frequency was higher in growing leaves than on the expanded leaves. Grazing efficiency was decreased as sward canopy height, especially at the end of growing season. Pastures manged at high canopy heigh allow animals maximize herbage intake, selection leaves instead of stems. Herbage mass and herbage allowance increased as sward canopy height was increased, providing an increase in average daily gain of animals (57 g BW/day) and therefore higher gain per unit area (262 kg LW/ha) at the lowest grazing intensity.

<p> Frequent droughts are common and extreme precipitation is a normal weather pattern for the Navajo country and has been for almost 6000 years. The Navajo do not abandon the often that drought stricken areas demonstrating their ability adapt to extreme weather conditions. For almost 300 years, the Navajo, while in a state of constant warfare with many different surrounding peoples, continued to develop and grow as a tribe, while living off of livestock, farming and hunting. Currently open for public review and comment is a new proposed Navajo Rangeland Improvement Act of 2014. It is the people, the tribal citizen&rsquo;s needs that need administration.</p><p>

Made available in DSpace on 2014-08-13T14:50:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-17Bitstream added on 2014-08-13T17:59:52Z : No. of bitstreams: 1 000770992_20150217.pdf: 243087 bytes, checksum: a90b3c03b76c6a08535e6f943d4b7d69 (MD5) Bitstreams deleted on 2015-02-18T15:02:18Z: 000770992_20150217.pdf,Bitstream added on 2015-02-18T15:02:49Z : No. of bitstreams: 1 000770992.pdf: 878622 bytes, checksum: 57403b297a66f823289c75003ed6eaa1 (MD5) / O sistema silvipastoril caracteriza-se por aumentar a produção de leite, com maior número de vacas por hectare, devido ao maior aporte de proteína na dieta. No sistema silvipastoril as vacas possuem a disposição para alimentação, além do pasto, pequenas árvores e arbustos. O objetivo do presente estudo foi investigar os principais indicadores de qualidade do leite e agentes causais de mastite em vacas criadas em sistema silvipastoril. Foram avaliadas a composição (teor de gordura, proteína, lactose, extrato seco, extrato seco desengordurado e nitrogênio ureico), contagem de células somáticas (CCS), contagem bacteriana total (CBT), ocorrência de mastite clínica e subclínica, isolamento microbiológico, perfil de sensibilidade bacteriana “in vitro” e detecção de resíduos de antimicrobianos/inibidores da multiplicação de micro-organismos, no leite de vacas, e do tanque de expansão e latões em propriedades do Vale do Cauca, Colômbia. Os teores médios dos principais constituintes do leite foram: 3,24% de gordura, 3,27% de proteína, 4,40% de lactose, 10,62% de extrato seco, 8,57% de extrato seco desengordurado e 15,82 mg/dL de nitrogênio ureico, enquanto do tanque de expansão e latões foi: 3,51% de gordura, 3,20% de proteína, 4,34% de lactose, 11,72% de extrato seco, 8,47% extrato seco desengordurado e 14,57 mg/dL de nitrogênio ureico. A celularidade média dos quartos mamários e do tanque de expansão e latões foram 141.252,75 CS/mL e 363.078,05 CS/mL, respectivamente. A CBT média dos quartos mamários e do tanque de expansão foram 4.466,84 UFC/mL e 24.547,01 UFC/mL respectivamente. Os principais micro-organismos isolados dos quartos mamários foram Staphylococcus spp. (17%), Corynebacterium bovis (5%), Staphylococcus aureus (4%), Streptococcus spp. (3%), Streptococcus dysgalactiae (2%) e Staphylococcus hyicus (1%), enquanto do tanque de expansão e latões foram identificados Streptococcus spp. (29%), ... / The silvopastoral system is characterized by increasing the production of milk with a greater number of cows per hectare due to the higher amount of protein in the diet. In silvopastoral system cows are fed in addition to pasture, with small trees and shrubs. The aim of present study was determinate the main indicators of milk quality and mastitis causal agents in cows bred on silvopastoral system. We evaluated the composition (fat, protein, lactose, solids, dry extract, nonfat dry and urea nitrogen), somatic cell count (SCC), total bacterial count (TBC), occurrence of clinical and subclinical mastitis, microbiological isolation, in vitro bacterial sensitivity profile and detection of antimicrobial/multiplication inhibitors residues in milk produced by cows raised in silvopastoral systems, as well as the bulk tank and churns in farms of Cauca Valley, Colombia. The concentration of the major constituents of milk were 3.24% fat, 3.27% protein, 4.40% lactose, 10.62% dry extract, 8.57% nonfat dry and 15.82 mg/dL urea nitrogen, while the bulk tank and churns was: 3.51% fat, 3.20% protein, 4.34% lactose, 11.72% dry extract, 8.47% nonfat dry and 14.57 mg/dL urea nitrogen. The cell count of the cows and the bulk tank were 141,252.75 CS/mL and 363,078.05 CS/mL, respectively. The TBC mean in cows and the bulk tank were 4,466.84 CFU/mL and 24.547.01 CFU/mL respectively. The main microorganisms isolated from the udder cows were Staphylococcus spp. (17%), Corynebacterium bovis (5%), Staphylococcus aureus (4%), Streptococcus spp. (3%), Streptococcus dysgalactiae (2%) and Staphylococcus hyicus (1%), while the bulk tank and churns were identified more often Streptococcus spp. (29%), Enterobacter cloacae (14%), Hafnia alveii (14%) and Streptococcus α-haemolytic (14%). Antimicrobial residues in cow milk and bulk or churn were detected in 30% and 86% respectively. The silvopastoral system is a good alternative to cow nutrition, however is important the ...