CONSERVB: A numerical method to compute soil water content and temperature profiles under a bare surface

A comprehensive, yet fairly simple model of water disposition in a bare soil profile under the sequential impact of rain storms and other atmospheric influences, as they occur from hour to hour is presented. This model is intended mostly to support field studies of soil moisture dynamics by our current team, to serve as a background for the microwave measurements, and, eventually, to serve as a point of departure for soil moisture predictions for estimates based in part upon airborne measurements. The main distinction of the current model is that it accounts not only for the moisture flow in the soil-atmosphere system, but also for the energy flow and, hence, calculates system temperatures. Also, the model is of a dynamic nature, capable of supporting any required degree of resolution in time and space. Much critical testing of the sample is needed before the complexities of the hydrology of a vegetated surface can be related meaningfully to microwave observations

Investigation of remote sensing techniques of measuring soil moisture

Major activities described include development and evaluation of theoretical models that describe both active and passive microwave sensing of soil moisture, the evaluation of these models for their applicability, the execution of a controlled field experiment during which passive microwave measurements were acquired to validate these models, and evaluation of previously acquired aircraft microwave measurements. The development of a root zone soil water and soil temperature profile model and the calibration and evaluation of gamma ray attenuation probes for measuring soil moisture profiles are considered. The analysis of spatial variability of soil information as related to remote sensing is discussed as well as the implementation of an instrumented field site for acquisition of soil moisture and meteorologic information for use in validating the soil water profile and soil temperature profile models

Concentrate levels and \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e affect rumen fluid-associated bacteria numbers in dairy heifers

Total viable rumenbacteria counts through the use of colony-unit forming assays lack accuracy because they only include culturable bacteria capable of initiating cell division. Thus, bacterial counts can be underestimated. The use of fluorescent characteristics of cell membranes allows flow cytometry to enumerate and distinguish dead from live bacteria cells. The objective of this experiment was to investigate the viable and total ruminal bacteria counts when 3 levels of forage:concentrate in diets were fed at restricted levels with the addition of Saccharomycescerevisiae (YC). Three cannulated post-pubertal Holstein heifers (age 18 ± 1.0 months) were fed corn silage (CS)-based diets in a 3-period (35 d) Latin square design. Heifers were fed the diets for 21 d with no yeast addition, followed by 14 d where yeast culture (YC) was added (1 g/kg as-fed basis); (Yea-Sacc1026, Alltech, Inc., Nicholasville, KY). A low concentrate (LC) TMR (80% CS, 20% concentrate; 12.4% CP, 35% NDF), a medium concentrate (MC) TMR (60% CS, 40% concentrate; 12.3% CP. 28% NDF), and a high concentrate (HC) TMR (40% CS, 60% concentrate; 12.6% CP, 25% NDF), were fed once per day. Rumenfluid was sampled − 2, 0, 2, 4, 6, 8, 10, 12 h after feeding. Samples were immediately stained with fluorescent dyes using the BacLight kit (Molecular Probes Inc., Eugene, OR) and analyzed with a Coulter XL-MCL single laser flow cytometer. Mean rumen viable bacteria counts linearly increased among treatments (4.96, 4.78, 6.73 × 1011 ± 0.53 × 1011 cells/ml; P = 0.02) for LC, MC and HC respectively, and YC addition increased number of viable bacteria cells (P \u3c 0.01). Total and viable bacteria counts decreased for the first 2 h after feeding then increased 4 h post-feeding. Dietary concentratelevel and YC can alter rumenbacteria counts as measured by this method

Insights in nutrition programs for the developing ruminant

As the world population grows and resources for food animal production become more limited, animal efficiency must increase. The dairy industry has made progress in reducing age at first calving from 27 to 25 mo., but heifers remain unproductive for over half of their life while still consuming resources. As pre-ruminants, offering restricted amounts of milk to neonatal heifers (conventional system) increases concentrate consumption which drives rumen development. However, accelerated milk programs improve pre-weaning growth rate and the balance between these two systems is still under continuous investigation. Solid feed is important for papillary and musculature development in addition to establishment of a microbial population, which increase transition success when calves are weaned gradually. Furthermore, the optimal target weight for calving is 550 kg at 23 to 24.5 mo., which increases 305-d lactation yield. Increased milk production is desired, but a costly rearing period without producing milk only increases as age at first calving increases, which also increases total number of replacement heifers and total herd green-house emissions. Strategies to achieve desired body weight and age at first calving while reducing input include, using compensatory growth, restricting intake and precision feeding. Compensatory growth can increase average daily gain and feed efficiency; moreover, precision feeding increases feed efficiency even further by reducing nutrient metabolic costs in comparison to ad- libitum systems. Restricting intake provides increased rumen retention time for fiber, non-structural carbohydrates, protein, and other nutrients to be highly digested. Nutrient digestibility is important when comparing these feeding methods because dry matter intake has the greatest impact on efficiency, specifically when different amounts of forages are fed. Using different strategies during the weaning, pre-pubertal and post-pubertal period of dairy heifers can significantly improve performance, nutrient and resources utilization during this conditioning growing phase of dairy cattle.A medida que la población mundial crece y los alimentos se vuelven más limitados, la eficiencia animal debe aumentar. La industria láctea ha progresado en la reducción de la edad al primer parto de 27 a 25 meses, pero las vaquillas siguen siendo improductivas durante más de la mitad de su vida mientras consumen recursos. Como pre-rumiantes, ofrecer cantidades restringidas de leche a las vaquillas neonatales (sistema convencional) aumenta el consumo de concentrado, lo que impulsa el desarrollo del rumen. Sin embargo, los programas acelerados de leche mejoran la tasa de crecimiento previo al destete y el equilibrio entre estos dos sistemas aún está bajo investigación continua. La alimentación sólida es importante para el desarrollo papilar y la musculatura, además del establecimiento de una población microbiana, que aumenta el éxito de la transición cuando los terneros se destetan gradualmente. El peso objetivo para el parto es 550 kg de 23 a 24.5 meses, lo que aumenta el rendimiento de lactancia de 305 días. Si no se reduce el periodo de cría, aumenta el número de vaquillas de reemplazo y las emisiones totales de gases invernadero. Las estrategias para lograr el peso corporal y la edad deseados al primer parto al tiempo que se reducen los insumos incluyen el uso de crecimiento compensatorio, la restricción de la ingesta y la alimentación de precisión. El crecimiento compensatorio puede aumentar la ganancia diaria promedio y la eficiencia alimenticia; Además, la alimentación de precisión aumenta aún más la eficiencia alimenticia al reducir los costos metabólicos de los nutrientes en comparación con los sistemas ad-libitum. La ingesta restringida proporciona un mayor tiempo de retención del rumen para que la fibra, los carbohidratos no estructurales, las proteínas y otros nutrientes sean altamente digeridos