Resistance parameters to gastrointestinal parasitosis in Zerasca breed: a Tuscany indigenous line.

Zerasca is an indigenous sheep breed in endangered status. That breed carries out a primary position in the safeguard of Tuscany biodiversity, typical production improvement and agricultural district protection. It is characterized by a quite big size and a white medium open fleece. The study took on natural rangelands around Zeri in Massa Carrara region, placed in the north part of Tuscany at an altitude of 600-1200 m above sea level. Rough countries with self-shown sloping pastures typify that area. The Zerasca positive resistance to adverse climate conditions underlines a fine adaptation to the whole environment. However, common shepherds’ habit is to treat animals twice a year with antiparasitarian drugs, mainly in consequence of the presumed loss of productions. Starting from these observations, we analyzed worm challenge in three Zerasca breeding under natural pasture, through faecal egg count, packed cell volume and classification of parasite species. The identification of animals resistant to gastrointestinal parasitosis and the recognition of relationships between sheeps pointed out the possibilities of evaluating genetic resistance. The purpose is to reduce antihelmintics, drugs’ residual in the soil and pharmacological resistance, so that the treatments limitated to the non-resistance subjects move significant economical and ecological implications in breeding management.