Reliability of pelvimetry is affected by observer experience but not by breed and sex: a cross‐sectional study in beef cattle

Pelvis size plays an important role to prevent dystocia in cattle caused by the foeto‐maternal disproportion in commonly primiparous females. The reproducibility and repeatability are 2 important aspects for the reliability of the measurements to use in the selection of cattle for culling. Pelvic measures were taken with a Rice pelvimeter from 224 young cattle (180 females and 44 males) of 4 beef breeds in South Africa. One experienced and 2 inexperienced observers each measured pelvic height and width twice. The proportion measurements with a maximum difference of 0.5 cm within animal compared to the first measurement by the experienced observer is around 80% and by the unexperienced observers around 50% for pelvic height and around 60% for pelvic width. Breed and sex don’t affect the reliability of pelvimetry by an experienced observer. Under‐ and overestimation of pelvis size was observed in inexperienced observers which seems to be unrelated to breed and sex.