Re: Growth Spurt or Supply Issues?
Supply doesn't just spontaneously "dry up". If a mom dries up, there's a reason. Sometimes it's something beyond her control, like pregnancy, or the negative impacts of hormonal contraception. But more often it's due to nursing less- even after 19 months of nursing, supply is controlled by demand. It sounds like you're nursing infrequently during the day and plan to be doing even less at night, so this is a time when you should be expecting supply to dwindle a bit. But as long as you keep nursing you will keep making milk.
This could all be a growth spurt- kids do continue to go through them throughout toddlerhood and childhood.
If you want to introduce animal milk to your child's diet, you can. You can also just continue to nurse- my understanding is that as long as you're nursing 3-5 times a day, you're meeting all your child's "dairy" needs by yourself. It sounds like you plan to drop down to 3 nursing sessions and one bottle, so you're still in that range.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"