At 5 months I just offered Ty 4 or 5 x 250lm bottles a day - sometimes he would drink the whole 250mls at every feed and other times he would only take 80mls at each feed. Solid feeds are additional to the 4/5 bottles. Up until around 8 months you are supposed to give milk before solids

You could always offer her water as well though if she is thirsty throughout the day... especially in this heat