Stage 2 of Labor.
Labor in this Red Holstein heifer is progressing nicely. The calf is in anterior presentation, dorso-sacral position, with normal posture. Both pasterns appear to extend 15 cm or more beyond the vulva, indicating that the shoulders have passed through the critical bony pelvic inlet. This further indicates that there is enough room for the fetal hips to pass between the iliac shafts.
Drost M (1982)