Circadian drinking during ad libitum and restricted feeding in pygmy goats

Abstract

Eating and drinking of eight pygmy goats were recorded during ad libitum and restricted feeding conditions. During ad libitum conditions, water and food consumption occurred throughout the day with a circadian distribution of food and water intake showing peaks at the beginning of the light phase and at the beginning of the dark phase. When access to food was allowed only at the beginning (09:00–11:00 h) and at the end (19:00–21:00 h) of the 12 h light phase, a peak of water intake occurred during the two hours preceding and the first hour following dark onset. Therefore water/food ratio was greater during the evening hours (19:00–21:00 h) than during the morning hours (09:00–11:00 h). The results show that pygmy goats having access to food twice a day for 2 h at the beginning and towards the end of the 12 h light phase concentrate their water intake mainly during the last two hours before and the first hour after dark onset. This may contribute to the concomitant high food intake because there is evidence for control of feeding by the osmolarity of the ruminal fluid. Furthermore, the divergent water/food ratio between morning and evening hours suggest a dissociation of the circadian drinking rhythm from eating.