Colorato State Univ. and Brazilian researchers used 43,511 records on Nellore heifers and young bulls to determine the heritabilities of yearling heifer pregnancy and scrotal circumference, and the genetic correlation between the two traits. The heritability estimates were high for heifer pregnancy and scrotal circumference, averaging 0.69 and 0.57, respectively. However, the genetic correlation between heifer pregnancy and scrotal circumference was relatively low, averaging 0.20. The authors noted that based on the results of this study, EPDs for heifer pregnancy can be used to select bulls for the production of fertile daughters, and would be considerably more effective than selecting on scrotal circumference EPDs. Nevertheless, their analysis revealed that scrotal circumference can be incorporated in a two-trait analysis to enhance the accuracy of prediction for heifer pregnancy EPDs in young bulls (Eler et al. 2004. J. Anim. Sci. 82: 5219).