The Grazing Livestock of San Jose Llanga: Multiple-Species Resource Use and Management and Productivity of Sheep

The main objective of the joint IBTA/SR-CRSP project in Bolivia was to assess the overall role of small ruminants in the ecological and economic sustainability of an agropastoral system. Prominent was a mandate for us to investigate: (1) Whether small ruminants were important contributors to environmental degradation; and (2) whether there were feasible improvements in management that could mitigate negative impacts of small ruminants on natural resources and increase efficiency of animal production (see Chapter 1: Project objectives and research approach). These issues are important in light of recent controversy concerning environmental degradation of the world’s rangelands. On one hand people and livestock are blamed (Sinclair and Fryxell 1985; Cloudsley-Thompson 1988) while on another hand climate, or change in climate, is cited as a key factor (Rasmusson 1987; Ellis and Swift 1988). If livestock are not to blame then efforts to de-stock traditional pastoral systems could be in error (Behnke and Scoones 1991)

Título en español.

Voluntary intake and apparent digestibility of an artificially dried tropical grass, Cynodon nlemfuensis variety nlemfuensis. was evaluated utilizing Holstein bull calves. Two regrowth ages of grass hays, 30 and 45 days, were fed to two groups of four calves each: 16 and 24 weeks old. The grass hays were analyzed for dry matter and crude protein and for fiber fractions according to Goering and Van Soest. There were no significant differences between means for voluntary intake (g/kg body weight (BW)/day) of the chemical constituents for the four calf-hay groups. However, the trend was for higher intake by the 24-week old calves fed the 30-day hay than by the other three groups. Among the 16- week old calves, there was a higher voluntary intake by those consuming the 45-day hay despite the slightly higher nutritive value of the 30-day hay. When the data were pooled across calf ages, voluntary intake of 30-day hays was greater than for the 45-day ones, although only differences in crude protein intake were significant (P < .05). Pooled across hay ages, voluntary intake by the 24-week old calves was significantly greater (P < .05) than by the 16-week old calves for dry matter and neutral-detergent fiber only, indicating that hay intake was related to reticulo-ruminal capacity. Differences in apparent digestibility were significant (P < .05) only for crude protein with the 24-week old calves fed the 30-day hay, having a greater coefficient of digestibility than the 16- and 24-week old calves fed the 45-day hay. Crude protein digestibility of the 30-day hays (pooled across calf ages) was significantly greater (P < .05) than that of the 45-day hays. Although not significant for all constituents, the values were higher for the 30-day hay than for the 45-day hay (pooled across calf ages) and for the 24- week old calves than for the 16-week old calves (pooled across hay ages).El consumo voluntario y la digestibilidad aparente de henos de yerba Estrella (Cynodon nlemfuensis variedad nlemfuensis) se evaluaron alimentando becerros de la raza Holstein. Ocho becerros entre 16 y 24 semanas de edad se alimenta ron con henos de yerbas de 30 y 45 días de edad. Se efectuaron determinaciones químico-analíticas de materia seca y de proteína bruta por el método de la AOAC y de las fracciones fibrosas por el método de Goering y Van Soest en las muestras de henos y de heces. No se obtuvieron diferencias significativas entre promedios de consumo voluntario de las fracciones químicas en los 4 grupos. Sin embargo, la tendencia fue para un mayor consumo por el grupo de becerros de 24 semanas de edad consumiendo henos de 30 días (grupo 24-30) que para los otros 3 grupos. Entre los becerros de 16 semanas de edad hubo un consumo voluntario mayor para el heno de 45 días, aunque el valor nutritivo del heno de 30 días fue superior. Independientemente de la edad de los becerros, el consumo voluntario de los constituyentes químicos del heno de 30 días fue mayor que el del heno de 45 días, aunque sólo el de proteína bruta fue significativo (P < .05). Independientemente de la edad de los henos, el consumo voluntario de los becerros de 24 semanas fue significativamente (P < .05) mayor que el de los becerros de 16 semanas para materia seca y fibra neutrodetergente solamente. Esto indica que el consumo de heno esta relacionado con la capacidad retículo-ruminal. Las diferencias en digestibilidad aparente en el grupo 24-30 fueron significativas (P < .05) sólo para proteína bruta, presentando un coeficiente de digestibilidad mayor que en los grupos 16-45 y 24-45. La digestibilidad de la proteína bruta del heno de 30 días fue significativamente (P < .05) mayor que la del de 45 días. Aunque no fueron significativos para todas las fracciones, la digestibilidad fue mayor en el heno de 30 días que en el de 45 días y en los becerros de 24 semanas que en los de 16 semanas

Título en español.

The effects of stocking rate and level of supplementation with concentrate on cows grazing intensively managed tropical pastures were measured with four treatments: grazing alone at 2.5 head per ha per year (T1); grazing plus concentrate at the rate of 1 kg per 2 kg of milk irrespective of daily yield (T2); grazing plus concentrates at the rate of 1 kg per 2 kg above 10 kg daily (T3); and grazing at 5 head per ha plus concentrates at the same level as cows in T2 (T4). All three supplemented groups (T2, T3 and T4) produced significantly greater yields of milk and fat. Average milk yields (kg, M.E. basis) were 3450, 5568, 4709 and 5462 for cows on T1, T2, T3 and T4, respectively. Cows on the higher level of supplement (T2 and T4) gained significantly more weight over the lactation period than cows on T1 and T3. The effect of the supplement appears to be greatest during the early part of lactation when physiological limitations on the consumption of pasture prevent sufficient nutrient intake to supply demand. Cows on T2 produced only 105 kg more milk than cows on T4, while the expected difference, based on increased pasture availability, was over 455 kg. The reduced difference in level of production is postulated as an effect of excessive pasture growth on both intake and diet selection. While milk production was highest for cows receiving the high levels of supplement (T2 and T4), expected return per lactation in income over the cost of supplements, lime and fertilizer were greatest for T3 (medium supplement). Expected returns on a per ha basis were greatest for T4 with 5 cows per ha. Results indicate that where land costs are high, most efficient use of pasture and concentrate resources may be reached by grazing at the rate of 5 head per ha and supplementing with concentrate at 1 kg per 2 kg of milk.Los efectos de la carga animal del pasto y el nivel de suplementación con alimento concentrado de cuatro tratamientos se midieron utilizando vacas que consumieron pastos tropicales cultivados intensivamente: pasto exclusivo a razón de 2.5 vacas por ha y año (T1); pasto más alimento concentrado a razón de 1 kg por 2 kg de leche, independientemente de la producción (T2); pasto más alimento concentrado a razón de 1 kg por 2 kg de leche producida sobre los primeros 10 kg (T3); y pasto a razón de 5 vacas por ha más alimento concentrado al mismo nivel que el de las vacas en T2 (T4). Los tres grupos suplementarios (T2, T3 y T4) produjeron cantidades mayores de leche y grasa que el grupo con pasto exclusivo (T1). Las producciones medias de leche (kg, a base del equivalente de madurez) fueron 3450, 5568, 4709 y 5462 para las vacas en los tratamientos T1, T2, T3 y T4, respectivamente. Las vacas en los niveles altos de suplementación (T2 y T4) ganaron significativamente mas peso durante el periodo de lactancia que las vacas en T1 y T3 . El efecto de la suplementación parece ser mayor durante la primera parte de la lactancia cuando las limitaciones fisiológicas en el consumo del pasto evitan el consumo de nutrimentos que suplan la exigencia del animal. Aunque la producción de leche fue mayor en vacas que recibieron los niveles altos de suplementación (T2 y T4), el beneficio esperado por lactancia en ingresos sobre el costo de los suplementos, cal y abono fueron mayores para T3 (suplemento mediano). El beneficio esperado por ha fue mayor para el tratamiento T4 con 5 vacas por ha, los resultados indican que, donde el costo del terreno es alto, el uso más eficiente de los pastos y alimentos concentrados se pueden alcanzar, al pastar a razón de 5 vacas por ha, suplementando la alimentación con pienso concentrado a razón de 1 kg por cada 2 kg de leche producida

Conclusions and Recommendations

Here we review brief summaries by chapter and then derive some integrated conclusions across chapters. Recommendations are presented with respect to further research, outreach and policy consideration. Because several years have passed between the end of our field work and publication of this synthesis volume, we end with an epilogue that highlights changes and key events that happened at San José Llanga (SJL) and with collaborating institutions in Bolivia between 1996-9

Magnetic susceptibility and VLF-R investigations for determining geothermal blowout contaminated area: a case study from Alaşehir (Manisa/Turkey)

Western Turkey is one of the most spectacular regions of widespread, active continental extension in the world. The most prominent structures of this region are E-W trending Gediz and Buyuk Menderes Grabens. Geothermal activity around city of Manisa in Gediz Graben has been investigated by many researchers and many geothermal boreholes were drilled in order to produce electricity. In the middle of May 2012, a geothermal blowout occurred 150 m away from the deep drilling (depth 1,100 m), in Alkan village of AlaAYehir resort in city of Manisa. After that, four big blowouts took place at the same area and thermal water had been diverted to Alkan stream for almost 4 months. The boron (B) and Fe levels of thermal water are 87 and 11.2 ppm where the background B and Fe values of topsoil vary between 0.2-1.5 ppm and 3.08-5.63 ppm, respectively. The objective of this study was to utilize joint magnetic susceptibility and VLF-R investigations to determine possibly contaminated area with B, related to high Fe level on the topsoil and thermal water in the subterranean layers. It is observed that magnetic susceptibility values vary between 500 and 790 cgs (x10(-6)) in the vicinity of blowouts and 150-340 cgs (x10(-6)) at a distance of 50 m around, where the background average value is 20 cgs (x10(-6)), by using the data collected at 346 stations. Besides, the VLF-R studies were carried out along 18 profiles at three different frequencies. Laterally constrained two-layer inversion was applied to each station; in addition to the inversion of all profiles for each frequency, all lines were stacked, 2-D resistivity maps were obtained, and the contaminated area was determined approximately as 35,000 m(2). The results show not only satisfactory agreement between magnetic susceptibility and VLF-R data, but also provide fast and valued interpretation of geochemical and geophysical properties of the geothermal contaminated area