I was through the Duis cow herd last September and the Lily cow was my pick at that time. Dottie has been a tremendous producer, however, she was starting to show her age. I purchased a flush in Lily in the Duis sale last fall.
In regards to Dottie being bred to calve, it is important especially in some of these older donors to allow them to have a natural calf every once in awhile. It will extend their flushing career, and extend their useful lives. There is a big difference between donors as to how many times they can be flushed before they need to be rebred. Some cows can be flushed every two months for a year or more, and some should be rebred after a couple of flushes.
Every time a cow is flushed, the lining of the uterus can have damage done to it, and this is why some donors will breed back and then lose the pregnancy. In the case of Dottie, the fact that she is rebred, and due to calve again is IMO very good news!