The objective was to describe genetic parameters and genetic changes in litter sizes at birth and weaning (LB and LW, n =9081), birth weight (BW, n =11,896), weaning weight (WW, n =11,104), fleece weight and grade (FW and FG, n =8872), and staple length (SL, n =1805) of Polypay sheep. Direct heritability estimates from single-trait analyses were 0.11 for LB, 0.02 for LW, 0.17 for BW, 0.18 for W...