A note on the variation and heritability of twinning in British Friesian cattle

Abstract

SUMMARYRecords of calving, excluding first calving, on 2862 cows, the daughters of 63 bulls used in AI were analysed to estimate the incidence and variation of twinning between bull progeny groups. The mean incidence of twinning was 2·8% and though the incidence increased with later parities the effect of parity was not significant. The incidence for bull progeny groups ranged from 0 to 8·8%. The intraclass correlation between parities for cows within bulls was 0·064±0·018 and a sire half sib group estimate of heritability for twinning, based on a single calving, was 0·43±0·012.