Some maternal factors associated with dystocia in Belgian Blue cattle

Measurements of conformation and pelvic characteristics of pedigree Belgian Blue cows were compared in cattle from 11 herds. In seven herds comprising 56 cows caesarean sections were routinely used to deliver pedigree calves and in four herds comprising 52 cows they were given the opportunity to cal ve naturally per vaginum. Cows in the seven herds were approximately 10 mon ths younger than those in the other herds. External pelvic measurements wer e linear distances between the tuber coxae, between the tuber coxarum and t he tuber ischium, between the tuber ischii, the vertical distance between t he underside of the tail and the tuber ischii, and heights of the tuber cox ae and tuber ischii from the floor. Internal pelvic measurements were the v ertical distance between the ventral body of the sacrum and the pubic symph ysis and the horizontal distance between the wings of the ileum at the wide st point of the pelvic inlet, both made with a Rice pelvimeter. Condition s cores were assessed for all cows. There were correlations (P < 0.001) betwe en internal pelvic height and width, external measurements, and age. For ca ttle that calved unassisted, pelvic height (P < 0.051 and area (P < 0.05) w ere significantly larger than those delivered by elective caesarean section . From internal pelvic measurements of 74 cows, those which always delivere d live calves had a larger pelvic area (P < 0.01) than cores that delivered a dead foetus following any parturition.