New module for prediction of reproductive traits EBV in Breedplan

BREEDPLAN publishes EBVs for days to calving (DTC) from natural mating (NAT) as the key measure of genetic merit for female reproduction. More recently, oestrus synchronization and artificial insemination (AI) have become more widely used in beef cattle in Australia to improve reproductive efficiency. The aim of this study was to develop a reproductive module to predict reproductive performance in beef cattle in Australia by using mating outcomes from AI, NAT from females and scrotal circumference (SC) in males. The study analysed mating and calving data collected on Angus cattle in Australia and New Zealand using the events-based recording system introduced in 2010. Genetic parameters for 1^st, 2^nd and 3^rd parities conception rate (CR) to AI and DTC from NAT were estimated. Mean CR from 1st, 2nd and 3rd parities of AI were 51.5%, 56.2% and 70.4% and for DTC of NAT were 303, 308 and 305 days, respectively. Estimated heritability for CR from 1^st, 2^nd and 3^rd parities were 0.15, 0.12 and 0.10 and for DTC were 0.05, 0.11 and 0.14, respectively. Moderate negative genetic correlations (-0.41 to -0.10) were estimated between CR and DTC of all three parities and were significantly lower than 1 suggesting that they were different traits. Therefore, there are benefits in genetic evaluation from including AI data and modelling parities as different traits.