Can you get some goats milk from the store, or do you have any cream? If you can only feed the regular cow's milk, it would be better to not water it down, to use whole milk and to add about half a teaspoon of cream to a cup of the whole milk. If you have any probiotics then add a pinch of it to the mixture. If you have a dropper, that would be better than using a straw. You have to be really careful to make sure you aren't squirting the milk in their mouth, but that they are lapping in up themselves, and be careful to not overfeed. When they strop eating eagerly, then you should stop. It's better to give them less milk and more feeding times, than too much milk at one feeding time. Make sure the babies are warmed up before feeding them, but it should be slow warming and be carful not to overheat them as well. You can use your own body heat to help warm them up, or a warm pack.