Observations on the effects of temperature and distance to water on the behaviour of Merino and Border Leicester sheep

Abstract

SUMMARYThe effects of ambient temperature on the daily behaviour patterns and water consumption of Border Leicester and Merino wethers were examined in an experiment where food was supplied ad libitum at points ranging from 2·4 to 5·6 km from water. The data were collected during a 12-week period when daily maximum temperatures ranged from 24 °C to 45 °C.At distances where twice-daily drinking appeared normal and maximum air temperatures exceeded 38 °C, Merinos abandoned the afternoon walk to water, and the Border Leicesters either abandoned the walk or reduced consumption. However, until the temperature reached 38 °C water intakes of both breeds were positively related to temperature. Border Leicesters increased consumption at a mean rate of 0·42 ± 0·072 l/head/°C until maximum ambient temperatures approached 38 °C, compared with the Merino rate of 0–17 ± 0·054 l/head/°C.Border Leicesters responded to temperature by drinking earlier in the mornings as minimum overnight temperatures rose, and by increased night activity when mean night temperatures exceeded 25 °C. Merinos showed no such response.