Changes of sodium appetite during the estrous cycle of sheep

The relative preference for sodium solutions and water was observed during a succession of estrous cycles in housed sheep. The luteal phase of the cycle was associated with statistically significant rises of sodium preference compared with the 6 days following estrus. These reflected changes in the intake both of sodium and water. The similar pattern with both bicarbonate and chloride suggests that it is the acceptability of the sodium which changes. The results are discussed in relation to sodium appetite and electrolyte homeostasis. The possible significance of any similar changes during the menstrual cycle is considered.