I finally made it to Oregon Zoo today to see Rose-Tu's calf, me and a hundred or so other people at 3 PM on a hot Thursday. He looked strong and capable, considering his age, and Mom was calm and attentive. A staff person said that the other two young cows, Shine and Chendra, have met him and that everyone behaved well. The zoo has a nice blog about the scene: http://www.oregonzoo.org/Rose_Tu/updates.htm
I took lots of blurry pictures, once again losing any claim to photographic competence. He nursed, walked, and took a dump. At one point it was very clear that this is indeed a bull calf. I could have watched him for hours, but other people wanted my space to take their own blurry pictures.
With a little luck, the cows will have a wonderful time with this baby. Usually the closer a group is to a normal social structure for their species (which means some youngsters running around!), the happier they all seem. And of course the other cows will learn about mothering. I know from my own experience how stressful these events are for staff--you have your heart in your mouth for days--and I am delighted to see how well its going.