Electronic identification of sheep in Sardinia: a retrospective analysis of the past fifteen years

This doctorate thesis provides a general background and new research findings on the electronic identification of ruminants. The first chapter is a literature review on electronic devices used for livestock identification. The other chapters describe experimental work on electronic identification devices, mostly in dairy sheep but also in goats. Chapter 2 deals with the effect of the presence and permanence time (from few days to 9 years) of four types of ceramic boluses (differing in capsule size, weight and material) used for electronic identification of Sarda sheep in six farms on the reticulum and chemical-physical characteristics of the interface surface. The boluses showed the presence of calcium, manganese, and zinc salts. The long-term permanence of the bolus in situ caused little changes in the mucosa which did not seem to impair the organ function. Chapter 3 comparing traditional and electronic animal identification in dairy sheep farms showed that the electronic identification device was more realiable, effective and efficient than the ear tag and ear tattoo. Chapter 4 studied possible correlations between the presence of rumen bolus and calcium content in blood, during pregnancy and lactation, and in milk in early, mid and late lactation in Sarda sheep. Calcium content in blood and milk did not differ between ewes with or without ceramic bolus. Chapter 5 concerns animal reading and data collection efficiency of automated milk recording in dairy sheep and goats.