Welcome to the forum! It sounds like you have an interesting question about the cow's udder. I'm glad you've come to the right place to find the answer. From what you've described, it sounds like the cow is having a normal response to having her udder filled for the first time. It's important to make sure she has the proper nutrition to ensure a speedy recovery. Best of luck to you and your cow!As the udder is stretched, especially for the first time, it's possible that capillaries in the udder can break. The blood generally disappears after a few days when the udder adjusts to being full. Making sure that the cow is getting an appropriate amount of calcium in her diet can help.