GPS Tracking of Sheep to Investigate Shelter and Shade Use in Relation to Climatic Conditions

In Australia inclement weather contributes to losses of new-born lambs and recently shorn sheep. Provision of forced shelter has been observed to reduce lamb losses by up to 10 percent and when given a choice, ewes preferentially seek shelter on offer for a limited period around two weeks post shearing (Alexander et al. 1980). Given shearing is not ideal in late pregnancy, alternative ways of attracting sheep to shelter are needed. This paper reports on the results of deploying GPS collars on sheep on a commercial property in the Northern Tablelands region of NSW Australia, with the aim of understanding the relationship between local climate and topography and sheep preference for shelter during pregnancy. In this work, two 14 ha field designs were evaluated. Field A comprised of perimeter shelter belts (3-4 rows of native trees) and individual, free standing trees within the field. Field B comprised of perimeter shelter belts, a single, internal shelter belt ('boomerang' shape) and a number of free standing trees. Over two shearing and lambing seasons a random sample of 5 ewes from two flocks of 200-300 ewes were fitted with GPS collars providing continuous (43-51 days) observations of the ewes' movement and proximity to shelter. Weather stations and temperature loggers were strategically located throughout the fields to provide localized measures of temperature, wind speed and precipitation.