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Contemporary animal agriculture is increasingly criticized on ethical grounds. Consequently, current policy and legislative discussions have become highly controversial as decision makers attempt to reconcile concerns about the impacts of animal production on animal welfare, the environment, and on the efficacy of antibiotics required to ensure human health with demands for abundant, affordable, safe food. Clearly, the broad implications for US animal agriculture of what appears to be a burgeoning movement relative to ethical food production must be understood by animal agriculture stakeholders. The potential effects of such developments on animal agricultural practices, corporate marketing strategies, and public perceptions of the ethics of animal production must also be clarified. To that end, it is essential to acknowledge that people's beliefs about which food production practices are appropriate are tied to diverse, latent value systems. Thus, relying solely on scientific information as a means to resolve current debates about animal agriculture is unlikely to be effective. The problem is compounded when scientific information is used inappropriately or strategically to advance a political agenda. Examples of the interface between science and ethics in regards to addressing currently contentious aspects of food animal production (animal welfare, antimicrobial use, and impacts of animal production practices on the environment) are reviewed. The roles of scientists and science in public debates about animal agricultural practices are also examined. It is suggested that scientists have a duty to contribute to the development of sound policy by providing clear and objectively presented information, by clarifying misinterpretations of science, and by recognizing the differences between presenting data vs. promoting their own value judgments in regard to how and which data should be used to establish policy. Finally, the role of the media in shaping public opinions on key issues pertaining to animal agriculture is also discussed.

Soil water, runoff amount and quality, pasture production and environmental data were measured for a pastoral prime lamb enterprise in the Central Tablelands of New South Wales from 1998 to 2002. There were 4 pasture treatments: fertilised and sown chicory (CH), fertilised and sown introduced pastures (SP), fertilised naturalised pastures (FN) and unfertilised naturalised pastures (UN). Two grazing management regimes, tactically grazed (TG) and continuously grazed (CG) were imposed on the SP, FN and UN treatments. The CH treatment was rotationally grazed.  To compare pasture and grazing system water use, maximum soil water deficit values (SWDMax) were calculated from neutron moisture meter data. SWDMax was influenced by both environmental and management factors. Management factors that influenced SWDMax were herbage mass of perennials, degree of perenniality, and the perennial species present. Environmental factors accounted for >50% of the variation in SWDMax. Inclusion of management factors (perennial herbage mass of C3 and C4 species and percentage perennial herbage mass), accounted for an additional 16% of variation. While the influence of pasture management appears to be relatively small, importantly, management is the only avenue available to land managers for influencing SWDMax. The UNTG and all sown treatments, with greater perennial herbage mass or greater C4 herbage mass consistently produced the highest SWDMax.  Runoff amount and quality data are presented for ground cover percentages which generally exceeded 80% for the experimental period. Runoff as a proportion of rain received during the experiment was <3%. Environmental factors explained 47% of variation in runoff, while pasture herbage mass and ground cover percentage explained an additional 2% of variation. Water quality was monitored on 3 treatments (SPTG, FNTG and UNCG) for total nitrogen (N), total phosphorus (P) and total suspended solids (TST) over a 6-month period. The mean values for total N and P were below the acceptable contaminant concentration for agricultural irrigation water. An important outcome of this research is the concept of a practical Targeted Water Management Plan (TWMP) which devises a framework for optimum water usage and productivity at a landscape scale.

The main limitations for prime lamb production in the Central Tablelands of New South Wales are low availability of forage early in the growing season (late autumn?early winter) and low nutritive value in the summer. This paper describes the performance of a first-cross lamb breeding enterprise on 4 pasture types and 2 management systems over 4 years for the Central Tablelands region. The pastures studied comprised a traditional unfertilised naturalised pasture, a similar pasture fertilised with superphosphate, a sod-sown fertilised introduced perennial grass pasture and a sod-sown summer growing perennial, chicory (Cichorium intybus L.) pasture. Grazing management involved either continuous grazing or tactical grazing that combined a lower annual stocking rate with an optional summer rest to maintain perennial grass content above 50%. An additional area of chicory pasture was set aside for finishing lambs. Over the experiment stocking rates were increased each year as the pasture became established, with increases ranging from 1.5 ewes/ha for tactically grazed unfertilised natural pasture to 3.6 ewes/ha, for chicory and clover pasture.  The feed quality v. quantity problem of summer and autumn was reaffirmed for each pasture type except chicory and the lamb enterprise appeared to be sufficiently adaptable to be promising. Ewes lambed in September and produced satisfactory lamb growth rates (about 280 g/day for twins) on the various pastures until weaning in late December. Thereafter, lamb growth rates declined as the pastures senesced, except chicory, reaffirming the feed quality v. quantity problem in summer and autumn of naturalised and sown grass pastures for producing lamb to heavyweight market specifications.  Weaning liveweights (in the range of 32?40 kg) from grass-based pastures were high enough for only about 45% of the lambs to be sold as domestic trade lambs with the remainder as unfinished lambs. In contrast, the chicory and clover finishing pasture produced lamb growth rates of 125 g/day and quality large, lean lambs suitable for the export market. Vegetable matter in the late January shorn wool was insignificant and there was no significant effect of pasture on fleece weight, fibre diameter or staple strength. Position of break in staples of wool from chicory pastures differed from that of the other pasture types and warrants further study on time of shearing. It was concluded that a first cross lamb producing enterprise of suitable genetics was effective in producing trade and store lambs before pasture senescence, but the inclusion of a specialised pasture of summer growing chicory would create greater opportunities. In the unreliable summer rainfall region of the Central Tablelands, the area of chicory pasture needed to maintain lamb growth rates of >125 g/day, estimated from these results, is around 10 lamb/ha of chicory.

This paper reports results from a large-scale field experiment conducted on a naturalised pasture at Carcoar, New South Wales, during the period 1997?2002. Here we describe the effect of pasture type and management on pasture productivity and composition, and discuss implications for long-term productivity. Four different pasture types (unfertilised naturalised, UN; fertilised naturalised, FN; fertilised introduced species, SP; and fertilised chicory, CH) were each subjected to 2 management strategies (continuously grazed, CG; and tactically grazed, TG). Stocking rate was set at a conservative level initially and then adjusted periodically based on ewe performance and minimum values of herbage mass (HM) in winter. TG involved a summer deferment when required and a lower stocking rate than on the CG treatment. CH was managed under a 4-paddock rotation. SP and CH also had 2.5 t/ha lime surface applied before introduced species being sod-sown.  Available herbage mass tended to peak during spring and summer and was lowest in late autumn?early winter. Under CG, application of superphosphate to the naturalised pasture increased herbage mass by up to 60%, but most of the response came from annual grasses (mainly vulpia and soft brome), and subterranean clover during spring. Fertiliser initially increased the herbage mass of perennial grasses relative to the unfertilised continuously grazed control, but this component decreased over time. TG increased the perennial grass content. Annual grass herbage mass was greater where fertilised and continuously grazed, but over time declined where unfertilised and/or tactically managed. Legumes were a minor component of these pastures, but were higher where fertilised and lower where tactically grazed. Net pasture growth rate (NGR) varied with seasonal conditions, and was higher where fertiliser was applied.   The data suggest that replanting perennial grasses is an effective process for increasing perenniality in this environment providing that it is economic. Further, the implementation of TG over summer has proved to be a useful approach for maintaining or increasing perennial content in existing pastures. However, there is a need to integrate TG with the timing of superphosphate application to maximise the effect on the perennial component and minimise dominance by annual species.

Temperate perennial grass-based pastures dominate the high rainfall zone of south-eastern Australia and support a major livestock production industry. This area has experienced a recent change in overall pasture condition, however, typified by a reduction in the abundance of perennial grasses and an increasingly prominent winter-annual grass weed component. Improving the condition and productivity of these pastures can be achieved by improved management but this requires better knowledge of the interactions between management options and pasture species composition and of the interaction between pasture vegetation and the complex effects of a heterogeneous landscape. This paper reports the results of an intensive survey of a 60-ha paddock that was designed to identify the species present, determine their patterns of distribution and examine the relationships between pasture vegetation and the environment. The survey of species present in late summer was supplemented by the identification of seedlings that later emerged from extracted soil cores and by soil physical and chemical analyses. Data were analysed using ordination and interpreted with GIS software so that topographic features could be considered.  The most frequently identified taxa were Hypochaeris radicata, Austrodanthonia spp. and Bothriochloa spp. (in late summer) and Vulpia spp., Bromus molliformis and Trifolium subterraneum (winter-annual species). Austrodanthonia spp. were commonly found on the drier ridges and more acid soils with lower phosphate levels. These were also the areas dominated in spring by Vulpia spp. and were generally lower in plant species richness overall. The most species-rich areas occurred downslope where soil fertility was higher and less moisture stress was presumably experienced. The measured environmental factors explained a substantial proportion of the variation in the vegetation dataset, which underlined the importance of considering landscape effects in the management of typical tablelands pastures.

Summary. Most currently used techniques for analysing the stability of near surface structures, such as rock slopes, are based on the application of the effective Coulomb shear strength parameters cohesion c′, and the angle of friction φ′ on some known or anticipated shear surface subjected to an effective normal stress σ′n. The most widely used of these techniques are the variants of the method of slices and related upper bound techniques. If the Hoek-Brown criterion is to be used to model the strength of near surface fractured rocks, it is necessary to determine equivalent Coulomb shear strength parameters for the specified level of effective normal stress. Calculation of the equivalent Coulomb parameters for the Hoek-Brown criterion for cases when a ≠ 0.5 is not a straightforward matter. A simple procedure for calculating instantaneous values of c′i and φ′i has been developed based on spreadsheet calculations and the application of a numerical optimisation routine. This procedure can also be applied to calculating the Hoek-Brown envelope plotted in shear stress/normal stress space. A simple closed form solution for c′i and tan φ′i has also been developed for the special case when a = 1. A three-dimensional version of the Hoek-Brown criterion has been developed by combining it with the Drucker-Prager criterion. This new yield criterion has been implemented by numerical solution of the governing equations. A simplification of this three-dimensional yield criterion has been developed by introducing an intermediate principal stress weighting factor. Comparison with published results demonstrates that this simplified criterion has the capacity to model the results of true triaxial tests for a range of different rock types over a wide range of stress levels. The new three-dimensional yield criterion has the advantage that its input parameters can be determined from routine uniaxial compression tests and mineralogical examination.

Summary The paper outlines a new method for estimating the distribution form, and mean size, of discontinuities from scanline data. By assuming that the discontinuities are circular discs it has been possible to apply existing solutions for the distributions of censored semi-trace lengths sampled by a scanline at an exposed rock face. These solutions have been implemented by numerical quadrature in a standard Excel spreadsheet, with solution optimisation achieved with Solver. Problems caused by a singularity in the integration were overcome by applying an integration offset parameter. A trigonometrical substitution for removing this singularity is also outlined. The numerical quadrature strategy was validated by comparison with the analytical solution for the uniform distribution, and by comparison with the results of an extensive geometrical simulation of the stereological process. A new distribution, here named the Wicksell distribution, has been identified. This distribution is characterised by the fact that the distribution of disc diameters and the distribution of complete traces on a cutting plane are identical. Two examples, based on real scanline data, are presented to illustrate the practical application of the new methods.

We examined diminutive colonic polyps to identify relationships between thermal electrocoagulation or resection trauma cytologic artifacts, type of thermal electrocoagulation, polyp size, and the interobserver variation among 3 pathologists. The 3 pathologists independently evaluated 119 colonic polyps 5 mm or less in maximum dimension for diagnosis and degree of thermal electrocoagulation or resection trauma cytologic artifacts. The maximum dimension of the polyps and type of thermal electrocoagulation were recorded. The average percentage of polyps in which a definitive diagnosis could not be made because of cytologic artifacts was 16.5% (range, 11.8%-19.3%). Decreasing polyp size was associated linearly with the inability to make a definitive diagnosis owing to cytologic artifacts. Polyps smaller than 2 mm significantly more often could not be definitively diagnosed by at least 1 pathologist owing to cytologic artifacts, including some polyps that were excised without thermal electrocautery. Interobserver variation increased with decreasing polyp dimension. Two millimeters seems to represent a cut point, below which the likelihood that a definitive diagnosis can be made can be increased if thermal electrocoagulation is used. This small size seems to make them especially susceptible to cytologically injurious forces.

TO THE EDITOR: —I have read with interest Dr. Mautz' letter on insomnia in The Journal of December 14. In my own case (I am of a nervous temperament) business affairs have often produced a sleepless night. I have tried counting, deep breathing, etc., (and have avoided drugs) without success. I have also tried getting up and walking around for a while, only to resume my busy thoughts on returning to the pillow. Suddenly an inspiration: Get out of bed; become interested in some humorous story, such as one of Mark Twain's; get to laughing; go to bed with a good giggle on; Morpheus takes a grip on the throat of business, and there you are—asleep.