WITHIN-HERD EVALUATION OF SOW REPRODUCTIVE TRAITS

A procedure for computing within-herd genetic evaluations of sows and boars for the reproductive trait of total number of pigs born that inc orporates national genetic evaluations of males and females is describ ed. National genetic evaluations and solutions for litter effects asso ciated with a particular herd are weighted according to the amount of national information each into a set of mixed model equations for that herd. Computer programs were written to run on a microcomputer and to handle a herd with up to 2000 sows. The concept is to provide interim genetic evaluations for total number born, as is currently done for g rowth rate and backfat thickness, in a timely manner for herd owners, and such that the evaluations make use of and can be compared with nat ional evaluations. The programs were field-tested in five Ontario herd s and evaluations of 1271 animals were examined. Correlations were 0.9 1 or greater between the interim evaluations and subsequent national e valuations and were 0.93 or greater between the interim evaluations an d the previous national evaluations.