Pelvic Measurements of Heifers: A Case Study in Hawaii

Abstract

Pelvic measurement (PM) can be used as a management tool in reducing the incidence and severity of calving difficulty (dystocia) in beef cattle operations. A large majority of calving difficulties occurs in first-parity heifers. By identifying and quantifying heifers' pelvic areas, ranchers can make informed culling decisions affecting the future productivity and economic success of the cow herd. We evaluated the impact of PM-based heifer culling decisions on the percent of calving losses at parturition. In total, 2244 long yearling heifers were measured using a Rice pelvimeter. Pelvic areas ranged from 133 to 255 cm2; heifers with pelvic area less than 187.5 cm2 were culled. Calving losses in the herd prior to PM were 7.18 ± 1.06, whereas losses after PM were 4.08 ± 0.28. Calving losses were significantly lower (P<0.05) when critical minimum pelvic area measurements were used as culling criteria, compared to the visual culling criteria used prior to PM. In summary, the use of PM can significantly reduce the incidence of dystocia in a commercial heifer herd when combined with a sound herd health and nutrition program for heifers and the use of "calving-ease" (low birth weight) bulls.