Foraging strategies and grazing behaviour as constraints in sheep production systems at northern Spain

Abstract

Topographical and climatic constraints mean that most of the upland and mountain areas of Europe are suited only to extensive systems of livestock production. Development of these less favoured regions must proceed in a way which provides a basis for the persistence of farming communities whilst simultaneously taking into account the increasingly important environmental aspects of land use. In mountain areas of Northern Spain the intensity of food selection during summer grazing season (June to October) was studied for the two main breeds of sheep (Churra and Merino). The seasonal variation in food selection is of importance when estimating intake in mountain sheep grazing systems. Seasonal differences were found between sheep breeds, with a significant decline in the proportion of leaf in the diet of the Merino during the dry period. An experiment was carried out with the aim of finding out how grazing behaviour varied in relation to food biomass availability in the presence and absence of an upper constraint of feeding time. For sward height of 3.5 cmtbe number of bouts and the total daily grazing time were lower than on a higher sward height of 5.5 cm. Ewes whose total daily feeding time was restricted experimentally compensated to some extent by taking fewer longer grazing bouts than unrestricted sheep. Both the intensity of food selection and grazing time are a consequence of seasonal quantity and quality variations in food availability, animal adaptation, traditional management imposed to counterac overnight predation and all these aspects must be considered in alternative sheep production systems.