in which Tb1j and Tm1j are truncation points of the joint distribution of meat (b) and maternal (m) genetic values, q1j is the proportion selected, and ρbm is the correlation between meat and maternal traits. Functions C05ADF and D01AMF of the NAG (Numerical Algorithms Group Ltd., Oxford, UK) library were used for accurate numerical integration of normal distributions. The selection intensity of any subsequent selection events was calculated based on the proportion selected at that stage and taking into account the reduction in genetic variance due to previous selection steps.