The Birthday White Park Calf is the offspring of a Bull and Birthday White Park Cow. When you harvest milk from your Dairy Farm (with 1 Bull and at least 1 Birthday White Park Cow inside) there is a chance that a Birthday White Park Calf will be born. When you harvest from your Cow Pasture with at least 1 Birthday White Park Cow there is a chance that a Birthday White Park Calf will be born.