The correlation between the growth of body measurements, age, breed and the growth of pelvic sizes of beef cattle in South Africa

Abstract

Dystocia is a problem in 15-30% of the births in beef cattle. Dystocia has economical losses but also has a negative impact on the health and welfare of the new-born calves. One of the reasons that can cause dystocia is a disproportional fetal-pelvic ratio. In this research we have measured animals of four different South African breeds, Brahman, Bonsmara, Nguni and Hereford. The measurements were done in two rounds with a 5 month interval. The body measurements which performed are body length, shoulder height and hearth girth. The date of birth is also collected from the animals and the pelvis height and growth is measured. All the collected measurements are put in a data set and a Multivariable General Linear Model is analysed. The results showed that for the growth of the pelvis width and area the breed had the best correlation, and for the growth of pelvis height the explanatory variables age, growth of body length and breed had the best correlation. But overall there is no strong correlation between the growth of the pelvis sizes and the growth of the explanatory variables, age or breed. The results also showed that for all three outcome variables (growth of pelvis height, width and area) there is a low R2 (25.8, 16.5 and 20.1%) with these explanatory variables. Therefore a high percentage of the variation in pelvis growth cannot be explained by the explanatory variables. Based on this study, it is difficult to draw a clear conclusion based on the correlation between growth of the pelvis and the measured variables.