ELASTOGRAPHY OF THE NORMAL CANINE LIVER,SPLEEN AND KIDNEYS

Elastography is a simple, expedient and noninvasive technique that may be used to assess the elasticity or stiffness of a tissue, in conjunction with traditional B‐mode ultrasonography. Quantitative assessment of tissue stiffness can be made which involves measurement of the shear wave velocity within the tissue of interest. The goal of this study was to assess the feasibility of elastography for clinical use in the abdomen of conscious small animals and to investigate factors that affect shear wave velocity measurement. Elastography was performed on the liver, spleen, and kidneys of 15 dogs at predefined depths within the parenchyma. Breed, age, gender, neuter status, and weight were documented for each animal. Depth at which measurements were taken had a significant negative relationship with the shear wave velocity value obtained. Individual dog effects, such as weight and gender, also appeared to have a significant effect on the shear wave velocity measurement for specific organs; weight had a significant positive effect on the shear wave velocity for each of the organs examined, whereas the effect of gender was inconsistent between organs (having a positive effect for the liver and a negative effect for the spleen). It is hoped that these results may act as a baseline to guide further work into the field of elastography in companion animals.     

Nutrient changes in potting mix and <Emphasis Type="Italic">Eucalyptus nitens</Emphasis> leaf tissue under macadamia biochar amendments

The effect of macadamia nut shell biochar on nitrogen, potassium, phosphorus, magnesium, calcium and sodium concentrations in potting mix used to grow Eucalyptus nitens seedlings was investigated in a glasshouse experiment. The treatments combined two fertiliser rates (50 and 100% rate of the commercial mix commonly used in forestry nurseries) with eight biochar rates (0, 2, 5, 10, 20, 50, 80 and 100 t ha^?1) arranged in a randomised complete block with three replicates of four sample plants. Nutrients were quantified in the potting mix and seedling leaves at four destructive harvests 135, 177, 219 and 269 days after planting. Biochar significantly increased nitrate-N, Colwell P, Colwell K and exchangeable Na and reduced ammonium-N, Mg and Ca concentrations in the potting mix. Seedling leaf concentrations of P, K and Na were increased by biochar application, while N remained dependent on fertiliser rate only. Mg and Ca leaf concentrations decreased in response to increasing biochar rates. Elevated nitrate-N and decreased ammonium-N concentrations suggest that biochar might have increased nitrification in the potting mix. We presumed that biochar mediated processes that reduced uptake of P and K when high doses of biochar were combined with full fertilisation. Changes in potting mix K, Na, Mg and Ca were consistent with selective adsorption of ions to biochar surfaces.     

Galloping exercise induces regional changes in bone density within the third and radial carpal bones of Thoroughbred horses

This study was performed to test the hypothesis that a localised bone hypertrophy could occur within the subchondral cancellous architecture of the third and radial carpal bones. Using 2 levels of controlled and defined exercise, it was observed that a high intensity treadmill exercise protocol resulted in functional adaptation of the carpal bones. The increase in trabecular thickening and density was seen to be localised to those regions underlying common sites of cartilage degradation, the interface of the thickened trabeculae with the normal architecture in the third carpal bone was coincident with a common site of clinical fractures. The bone changes were determined both qualitatively on examination of slab radiographs and quantified by dual energy x-ray absorptiometry. The findings from this study are relevant to mechanical factors involved in the pathophysiology of joint degeneration. The potential clinical implications of this study are in relation to changes in the type and duration of exercise regimens used in training of equine athletes. The rapid response of bone to mechanical stimulation has implications in the longer term for localised cartilage degradation. Imaging techniques could be developed to monitor these early bone changes in the specific areas identified in this study and thus allow appropriate changes in training intensity to minimise subsequent damage to the articular surface.     

Modeling Spatial Variability of Soil Chemical Parameters for Site-Specific Farming Using Stochastic Methods

Spatial variability of soil properties affects nutrient transport in the field. The purpose of this study was to examine the extent of spatial variability in the soil chemical parameters, and to develop stochastic models to represent these variations. The parameters selected include concentration levels of Ca, Mg, Mn, NO3-N, P, K and Zn, and OM and pH of soil. Data were collected from 55 grids of 20 × 20 m size from a field within the Coastal Plains of Virginia. Analyses were performed based on the deterministic and stochastic components of the chemical parameters. All the parameters had different degrees of variability in the spatial domain. NO3-N, P, K and Zn exhibited greater degrees of variability compared to other parameters. Among the nine parameters, NO3-N and Zn had the greatest spatial variation with coefficient of variation (CV) of 40 and 49%, respectively, while pH had the lowest variation with a CV of only 4%. The spatial variations of each parameter were not random, but were mutually correlated with their values at the adjoining grids. The analysis showed that the deterministic component of these parameters could be represented by a Fourier series containing sine and cosine functions, while different types of models were required to describe their stochastic component. A second-order autoregressive model, AR(2), for Ca, Mg, Mn and OM; a first-order autoregressive model, AR(1), for pH; and a mixed autoregressive-moving average, ARMA(2,1), for NO3-N, P, K and Zn parameters were found suitable. These models were capable of describing the spatial structure of chemical parameters, and hence can be used to determine their values at any unsampled locations to develop site-specific nutrient management plans for the study site.     

The impact of dystocia on dairy calf health,welfare, performance and survival

Up to one-third of dairy calves are born after dystocia and this is a major cause of calf mortality. This study investigated the neonatal physiology, survival, health and subsequent growth of dairy calves following dystocia and is the first longitudinal study to analyse multiple effects and to look beyond the perinatal period.A total of 455 live born Holstein calves (N: No assistance, n = 360; FN: Farmer assistance but normally presented calf, n = 82; FM: Farmer assistance of malpresented calf, n = 13) were followed from birth to first service (heifers) or until leaving the farm (bulls). Compared to N calves, FN and FM animals had higher salivary cortisol concentrations at day 1 (P < 0.001) and FN calves had lower passive immune transfer (P = 0.03). Dystocia had no biologically significant impact on rectal temperature throughout the first 4 days (P > 0.05). During the first 60 days, FM calves had a higher proportion of days with non-routine health treatments (P < 0.05) and, by the time of weaning, mortality in FN and FM heifers was higher than in N calves (2.8×; P < 0.01). However, in surviving calves, growth to first service was not affected by dystocia category (P > 0.05).Calves which survive dystocia experience lower passive immunity transfer, higher mortality and higher indicators of physiological stress. Such calves have poorer welfare in the neonatal period and possibly beyond. Strategies need to be implemented to improve the subsequent health and welfare of such calves and to lower the incidence of dystocia.     

Expansion profiles of wheat doughs fermented by seven commercial baker's yeasts

Commercial baker's yeast consists of Saccharomyces cerevisae, however the strain can vary in each baker's yeast, which might influence the dough fermentation time. The scope of this research was to investigate the dough expansion of wheat doughs fermented by seven commercial baker's yeasts at different yeast concentrations (2.88·10¹¹, 5.76·10¹¹ and 8.64·10¹¹ colony forming units/kg flour) and fermentation temperatures (5 °C, 15 °C, 25 °C and 35 °C). Dough expansion was investigated by monitoring the dough height and it was found to be described well by a first order kinetic model. Doughs fermented with four of the seven yeasts generally had higher kinetic rate constants and hence shorter fermentation times compared to fermentation with the other three yeasts. The shortest fermentation times were found for doughs fermented at 25 °C and the highest yeast concentration, a trend found for all the yeasts tested. The differences in the kinetic rate constants indicate a differentiation in yeast strain among the commercial baker's yeasts emphasising the great importance of the choice of baker's yeast for the dough fermentation time.     

THE EFFECT OF WEEDS, AND THEIR CONTROL BY MCPA SPRAYING, ON THE ESTABLISHMENT OF PERENNIAL RYEGRASS AND COCKSFOOT IN THE KENYA HIGHLANDS

The vigour of perennial ryegrass and cocksfoot after spraying with the sodium salt of MCPA during establishment was estimated from their yields in small-plot cutting experiments on weedy land. Where the weed yields of control plots was of the order of a ton of air-dry matter an acre (mostly Spergula arvensis L.), spraying at up to 1·2 1b. acid equivalent an acre caused twofold to threefold increases in grass yields. The optimum time to spray perennial ryegrass was at the three- to four-leaf stage or 26 days after sowing; for cocksfoot, which appeared more susceptible to the herbicide, spraying at the tillering stage, or about 40 days after sowing, was best. Increasing the seed rates of ryegrass produced transitory increases in yields while decreasing weed yields. Increasing phosphate or nitrogen caused decreases in weed yields. Although the former gave a large increase in weed yield in the first cut this was offset by a large decrease in the second cut. There was an indication that the level of nitrogenous manuring affected the toxicity of the herbicide to the grasses.     

The Nature and Distribution of Metals in Soils of the Sydney Estuary Catchment, Australia

Total topsoil 50th percentile Cu, Pb and Zn concentrations (n?=?491) in the Sydney estuary catchment were 23 ??g?g^?1, 60 ??g?g^?1 and 108 ??g?g^?1, respectively. Nine percent, 6% and 25% of samples were above soil quality guidelines, respectively and mean enrichment was 14, 35 and 29 times above background, respectively. Soils in the south-eastern region of the catchment exhibited highest metal concentrations. The close relationship between soil metal and road network distributions and outcomes of vehicular emissions modelling, strongly suggested vehicular traffic was the primary source of metals to catchment soils. Catchment soil and road dust probably make an important contribution to contamination of the adjacent estuary. The concentration of soil metals followed the land use trend: industrial?>?urban?>?undeveloped areas. A high proportion (mean 45%, 62% and 42%, for Cu, Pb and Zn, respectively) of metals in the soils may be bioavailable.     

A Bayesian hierarchical analysis to compare classical and atypical scrapie surveillance data; Wales 2002-2006

We describe the application of Bayesian hierarchical models (BHM) to the analysis of risk of sheep scrapie using data from multiple surveillance sources. More specifically, we analysed data from the test results of three surveillance sources on classical and atypical scrapie in Wales for the period 2002-2006. For each form of scrapie, a BHM was fitted to assess the occurrence of spatial patterns of risk shared by the multiple surveillance sources and the association between covariates and disease. We defined a shared-component model whereby the two types of data sources: exhaustive lists (e.g. reports of clinical cases) and sample-based data sources (e.g. abattoir survey) shared a common spatial pattern of risks at parish level. This shared component was adjusted by a risk-gradient parameter that moderated the individual contribution of the datasets. For both forms of scrapie, the risk-gradient was not significantly different indicating that the sensitivity of the two types of dataset was similar for the two diseases. The spatial patterns of the combinations of data sources appeared similar within disease. However, our results suggest that classical and atypical scrapie differ in their spatial patterns and disease determinants. The joint approach permitted inference from all the available evidence and resulted in robust and less biased estimates of risk, particularly for atypical scrapie where the number of observations was very limited.