I also started Calum on a staw cup last week, during our holiday he much prefered drinking from our water bottles than his sippy
So I bought him a trainer straw cup when we got home.
He even took his milk out of it one morning, when I had run out of bottles.....
.....From experience is better to start giving your baby milk in a cup as soon as you can to get them use to it. At 12months someone LO's bottle free and are taking milk in a cup.
The cup challengeTo ease the transition from breast or bottle to cup, Professor Wolke suggests letting your child bite with his gums, suck and otherwise manipulate an empty cup or trainer cup starting at
about six months. When your baby becomes accustomed to playing with it, offer him water or diluted juice in a cup at snack time. It should help ease the weaning process for both of you.
pampers.com