Pelvic dimensions in phenotypically double-muscled Belgian Blue cows.

Some anatomical characteristics of 507 Belgian Blue (BB) cattle, withers height (WH), heart girth (HG), the distance between the two tubera coxae (TcTc) and the distance between the two tubera ischiadica (TiTi), were compared with the internal pelvic measurements of width, height and area. Mean values were 58.9 ± 6.2 cm for TcTc, 14.6 ± 2.3 cm for TiTi, 15.2 ± 2.1 cm for pelvic width (PW), 18.8 ± 1.9 cm for pelvic height (PH) and 288.5 ± 60.9 cm(2) for pelvic area (PA). Cows that calved per vaginam had larger WH (p < 0.05), TcTc (p < 0.05) and TiTi (p < 0.001) and internal pelvic measurements [PH and PA (p < 0.001)] compared with those whose parturition was managed by caesarean section (CS): Correlations between internal pelvic measurements and TcTc were higher (r = 0.58-0.63) than TiTi (r = 0.22-0.28). Correlations between other external body measures such as HG and WH with the internal pelvic measurements were even higher for HG (r = 0.69-0.74) and for WH (r = 0.67-0.74). HG and WH, together with internal pelvic measures, may be added to estimated breeding values (EBV's) that should assist breeders in selecting cows that can calve per vaginam, thereby reducing the breed's dependence on elective CS for maintaining its unique characteristics.