Factors affecting dystocia in range beef heifers

TitleFactors affecting dystocia in range beef heifers
Publication TypeThesis
Year of Publication1975
AuthorsCadle, Jr. JMark
Number of Pages68
Date Published1975
UniversityNew Mexico State University
CityLas Cruces, New Mexico
Thesis TypeM.S. Thesispp
Call Number00473
Keywordscattle breeding, dystocia, cattle reproduction, dystocia, disease,dystocia, dissertation, dissertations, dystocia, reproduction, also SEE <CATTLE REPRODUCTION>, theses, thesis
AbstractFifty-five primiparous heifers belonging to the Brangus, Hereford, Brangus X Hereford and Hereford X Brangus breeds were used to study factors affecting dystocia. Characteristics of the dam including height, weight, measurements between the hook bones, hook and pin bones, pin bones, horizontal and vertical pelvic dimensions and pelvic area were measured in October, December and February. Calf sex and individual calf measurements including head width, shoulder width and birth weight were determined within 24 hours after birth. Correlations for the three periods of measurement suggested less dystocia for progressively larger framed and heavier dams. Dam body weight had significant negative correlations (P<.05) to dystocia for the three times of measurement. Dam height was found to have significant negative correlations (P<.01) and (P<.05) to dystocia for December and February. Only when taken in December did the hook-pin measurement have a significant negative correlation (P<.05) to dystocia, and only when taken in February did the hook-hook measurement have a significant negative correlation (P<.01) to dystocia. Pelvic area was significantly correlated (P<.01) to dystocia when pelvic area was obtained in December or February. Stepwise regression for each of the three months of measurement indicated a more reliable prediction of dystocia the closer to term the variables are considered. Thirty-eight percent, 43% and 45% of the variation in dystocia score for October, December and February, respectively, was accounted for in the regression equations.