Modelling reproduction in a herd of dairy cattle

A dynamic stochastic model to simulate the reproductive process in a herd of dairy cattle has been constructed. The next event scheduling approach was utilized with four events being specified: perturition, ovulation, embryonic loss and replacement.The control variables included in the model are first breeding policy (1BDG), reproductive culling policy (RCLG), heat detection program (HDPM), breeding program (BDPM) and service sires selection program (SSPM). In addition, the model uses numerous endogenous variables such as parturition type (PRTY), oestrus behaviour (EBHV), cow's fertility (CFTY), embryonic mortality (EBLS), non-reproductive culling rate (NRCL) and others.The model was evaluated against independent experimental results. The simulated result closely approximates the average reproductive performance and variability of reproductive performance in a dairy herd.