Genetics and tolerance to tick-borne diseases in South Italy: experience in studying native Apulian and exotic sheep breed.

Tick borne diseases (TBDs), though neglected, are possibly the major constraints for livestock and agricultural production in southern Italy. The diseases affect mainly the livestock imported from foreign Northern countries. But now, very timidly indeed, the awareness that the use of native breeds could contribute to reduce the ravages of these diseases is growing. Over a period of many centuries Apulian farm animals have naturally developed the ability to thrive in TBDs endemic areas. This trait, which can be defined as tolerance to TBDs is associated with the ability to control parasitaemia and to resist the development of anaemia in the face of infection. It is a matter of fact that the hematological features of Apulian native farm animals are rather peculiar as the authors highlighted by studying the blood of these animals over a period of more than ten years. In the light of their experience the authors considered that the phenomenon of tolerance is a broad-based one and possibly not unrelated to the erythropoietic system of the Apulian animals. Thus the ability to resist anaemia per se was tested in four Altamurana sheep compared to that of four Romanov sheep. This work summarises the results obtained from the experimental anaemization of the above two breed groups and discusses the findings on the basis of a review of the authors' experience in studying TBDs in sheep.