RESUMO
Water is an essential source of life and is available to animals as free water, water content of feed, film water (e. g. dew) and metabolic water. The water requirements of small ruminants are influenced by the type of feed, climate, stage of production, type and length of the fleece or hair coat, husbandry factors and the general health of the animal. Differences in water metabolism, drinking behaviour and the efficiency of temperature regulation are further influenced by species, breed, production type, husbandry system, acclimatisation and adaptation. Small ruminants have been, and are still predominantly kept in extensive husbandry systems. They are therefore genetically and phenotypically well adapted to these conditions and possess a range of physiological and behavioural mechanisms to deal with adverse and suboptimal weather conditions. Regarding animal welfare, there is considerable debate in the discussion and assessment of what constitutes a sufficient water supply for small ruminants under different husbandry conditions, often involving differences between theoretical demands and practical experience. This publication reviews and summarises the current literature regarding water requirements, water metabolism and thermoregulatory mechanisms of small ruminants to provide the basis for an informed assessment of extensive husbandry systems in terms of compliance with animal-welfare requirements.