The repeatability of auxiliary sire indices was examined using first lactat
ion data of Holstein-Friesian crossbred cows. Age at first calving (AFC), f
irst service period (FSP), first lactation length (FLL), first dry period (
FDP) and first calving interval (FCI) were used as auxiliary traits in the
present study. There was 5.26% increase in accuracy of sire evaluation when
FLL, was used as auxiliary trait, for other auxiliary traits the gain was
very less. Similarly, number of daughters' records required for a pre-assig
ned level of accuracy was also less in case of FLL as auxiliary trait. The
repeatability of breeding value estimates was obtained by determining the c
orrelation of the breeding value of sires' estimate based on 5, 8 and 12 da
ughters with that of 'true' breeding value (based on 15 or more daughters r
ecord). The repeatability of auxiliary sire evaluation was higher when prog
eny group size per sire was small ranging from 5 to 8. With the increase of
daughter number there was no advantage of incorporation of auxiliary trait
s over sire evaluation based on milk yield record of daughters.