A new study has found that sheep forage differently and avoid parasites differently depending on how healthy they are.
The research was conducted by the University of Bristol and published in ‘Proceedings of the Royal Society B’.
The study used remote GPS sensing data to monitor the grazing patterns of the flock. Researchers, from Bristol’s School of Biological Sciences and Vet School, fitted 23 individual ewes with GPS trackers that were set to record their location every two minutes. The study took place in the uplands of Dartmoor over a period of 8 days.
The location recordings were then analysed against satellite data of vegetation quality, tick prevalence and parasite load and health measures for each sheep.
The data showed that less healthy ewes chose to avoid the higher quality vegetation, which is where ticks are generally found. While healthier sheep favoured the high-quality forage, despite the risk of infection from ticks.
Caroline Liddell, a Natural Environment Research Council (NERC) PhD student from Bristol’s School of Biological Sciences and the study’s lead author said:
“Discovering that the trade-off between maximising forage intake and minimising parasite encounter depends on the health status of individual sheep emphasizes the need to study livestock as individuals, even in group-living animals such as sheep. GPS tracking technology provides a feasible and increasingly affordable means of obtaining such individual-level data.
“Our study, which used extensively grazed sheep as a model system, opens new possibilities to study free-living grazing systems, and illustrates the benefits of using GPS technology to advance our understanding in this area.
“Future studies could use controlled interventions, such as antiparasitic treatment, to separate cause and effect and develop an understanding of the processes generating the observed associations.”