Towards a Virtual Fencing System: Training Domestic Sheep Using Audio Stimuli.

Fencing in livestock management is essential for location and movement control yet with conventional methods to require close labour supervision, leading to increased costs and reduced flexibility. Consequently, virtual fencing systems (VF) have recently gained noticeable attention as an effective method for the maintenance and control of restricted areas for animals. Existing systems to control animal movement use audio followed by controversial electric shocks which are prohibited in various countries. Accordingly, the present work has investigated the sole application of audio signals in training and managing animal behaviour. Audio cues in the range of 125-17 kHz were used to prohibit the entrance of seven Hebridean ewes from a restricted area with a feed bowl. Two trials were performed over the period of a year which were video recorded. Sound signals were activated when the animal approached a feed bowl and a restricted area with no feed bowl present. Results from both trials demonstrated that white noise and sounds in the frequency ranges of 125-440 Hz to 10-17 kHz successfully discouraged animals from entering a specific area with an overall success rate of 89.88% (white noise: 92.28%, 10-14 kHz: 89.13%, 15-17 kHz: 88.48%, 125-440 Hz: 88.44%). The study demonstrated that unaided audio stimuli were effective at managing virtual fencing for sheep.

Source-pathway-receptor investigation of the fate of trace elements derived from shotgun pellets discharged in terrestrial ecosystems managed for game shooting.

Spent shotgun pellets may contaminate terrestrial ecosystems. We examined the fate of elements originating from shotgun pellets in pasture and woodland ecosystems. Two source-receptor pathways: i) soil-soil pore water-plant and ii) whole earthworm/worm gut contents--washed and unwashed small mammal hair were investigated. Concentrations of Pb and associated contaminants were higher in soils from shot areas than controls. Arsenic and lead concentrations were positively correlated in soils, soil pore water and associated biota. Element concentrations in biota were below statutory levels in all locations. Bioavailability of lead to small mammals, based on concentrations in washed body hair was low. Lead movement from soil water to higher trophic levels was minor compared to lead adsorbed onto body surfaces. Lead was concentrated in earthworm gut and some plants. Results indicate that managed game shooting presents minimal risk in terms of element transfer to soils and their associated biota.

Seasonal influences on quantitative changes in sweat-associated anatomy in native and thoroughbred horses.

Stereological techniques were used to assess seasonal influences on morphometric characteristics of hair follicles, sweat and sebaceous glands in abattoir pelts of ponies (PN), thoroughbred (TB) and non-thoroughbred (NTB) horses. Volume density of sweat glands increased significantly from winter (0.061) to summer (0.098) in TB, and showed no change in NTB and a positive tendency in PN. There might be a body surface area : volume effect for sweat gland parameters as PN had smaller values than either TB or NTB, probably attributable to control of heat loss in winter. In summer, the skin remained thick and the volume density of sebaceous glands was increased in NTB, in contrast to TB where both were decreased. It is possible that in summer, sebum has a particular importance in NTB to enhance wicking of sweat through the pelt. TB showed significantly higher volume measurements of sebaceous glands than NTB and PN for winter: sebum has probably a special importance for water-proofing in TB in winter. PN showed no significant seasonal changes in sebaceous glands, but had a thinner summer skin. Winter values for hair follicle volume density between equine groups were similar (TB, NTB 0.066; PN 0.059), as was skin thickness (1.14-1.19 mm). The volume density lowered significantly in summer in TB and NTB. The volume of hair follicles under a unit area of skin surface decreased significantly in TB and nonsignificantly in NTB and PN. The seasonal adaptations of the skin shown here were most pronounced in TB and differed between breeds.

A simple water-filled plethysmograph for measurement of limb blood flow in humans.

Fundamental principles underpinning the study of cardiovascular physiology can be emphasized by measuring blood flow. Plethysmography is an appropriate, noninvasive technique to use but may not be available to some institutions. Therefore, for measurement of blood flow in human limbs, we developed a simple water-filled plethysmograph that may be built with minimal technical support. The device is formed from a plastic cylinder and houses a latex sleeve sealed at either end by means of circular flanges and rubber O-ring seals. Limb volume changes are transcribed using an air-filled piston recorder. This instrument proves to be sensitive and accurately determines limb volume changes over time. Utilizing an appropriate venous occlusion protocol, predicted vascular responses to postural challenge and physical exercise may be followed. In response to a questionnaire, a majority of students (n = 33) agreed that performing blood flow measurements succeeded in relating theory to practice, improved technical and observational skills, and made the learning experience real. This modified plethysmograph proves to be a valuable teaching tool in human physiology classes.