ABSTRACT
In subtropical drylands (the main regions where pastoralism is practiced) both forage/ fodder and drinking water can have a high salt content so that livestock can have an excessive intake of sodium, potassium or even magnesium salts. Livestock with a restricted water supply may be able to avoid water defi ciency by selectively grazing/ browsing plants high in moisture content. However, in many of the pastoral areas high moisture content is often associated with a high salt content, and selectivity of a low salt diet may differ from that of a high moisture diet. The tolerance of livestock to salt intake is matter of considerable interest in pastoral zones (Edwards et al. 1983). There is a hierarchy of tolerance within livestock species. Camels are most tolerant and cattle and horses least tolerant with sheep and goats in between (Silanikove 1989). Given the capacity of sheep to survive in arid regions, their regulation of salt and water balance may be geared towards coping with salt loads or water shortages, and hence the opportunity to increase the consumption of (or preference for) high-salt diet.
