If given free access to water, the volume of water drunk and the drinking frequency depends on:

• The nature and consistency of the feed
• Ambient temperature
• Amount and type of exercise
• Loss of fluid due to sweating
• Exertions such as those caused by the breeding period, hierarchic fights and fear (Schäfer 1993)

Pregnant mares drink more frequently, taking in smaller amounts of water. Horses prefer to drink with their necks extended, from watering holes or water troughs close to the ground. If horses have free access to water, they will drink according to their rank within the herd or group.