Determinants of the use of pastures by grazing horses

Abstract

In an agricultural context promoting the development of sustainable grazing systems, horses have a significant role to play in the mana-gement of grasslands and their biodiversity. While the number of horses has been increasing in France and in Europe, the lack of data on how horses exploit pastures makes it difficult to propose management recommendations, although there is evidence that grass can cover the nutritional requirements of horses, and that pasture management can be used to manipulate vegetation dynamics. Our aim was to review recent knowledge of factors that affect the voluntary intake and feeding choices of grazing horses. Comparing these results with similar measurements that were made in ruminants will highlight the specificities of horses’ feeding strategies. In order to cover their nutritional requirements, horses adjust their foraging behaviour (daily grazing time, instantaneous intake rate, feeding site selection) when facing variations of resource availability and quality. Their preferential selection of short vegetation regrowths is likely to favour vegetation and animal diversity by creating relatively stable open patches in pastures. In the future, we will analyse the effects of further animal characteristics and pasture management in order to produce practical recommendations for horse breeders.