Effectiveness of sire evaluation for milk yield with auxiliary traits in Hariana cattle

Abstract

Investigation was carried out to study the effectiveness of sires' breeding values using auxiliary traits on daughters in combination with first laclation yield (FLY) in relation to sire evaluation for individual traits by different methods. The data on 617 Harinna cows maintained at government livestock farm, Hisar, over 27 years (1973-2000) were analyzed. The auxiliary traits included were age at first calving (AFC), first service period (FSP), first calving interval (FCI). first lactation length (FLL), first lactation peak yield (FPY) and first dry period (FDP). Sire evaluation for FLY was done by daughter's average (DA), contemporary comparison (CC), Least-squares (LS), simplified regressed least-squares (SRLS), best linear unbiased prediction (BLUP) methods and by incorporating 1 auxiliary trait. The results showed that BLUP was the best method of sire evaluation having the lowest error variance. The relative efficiency of all other methods was very low to the BLUP. Highest association was obtained between breeding value and rank on the basis of SRLS and LS. Among the sire indexes with auxiliary traits the error variance was very high for all the traits. being lowest with AFC. It may be inferred that BLUP is the most efficient method of sire evaluation for FLY and nothing is gained by incorporating any auxiliary trait. With auxiliary traits, the number of daughters required for a predefined level of accuracy for sire evaluation differed significantly only with AFC. Only half the number of progeny per sire was sufficient to attain the same level of accuracy with AFC as auxiliary trait rather than evaluating sires on FLY alone. It was further revealed that using AFC as auxiliary trait with FLY results into higher accuracy than on FLY alone in smaller progeny group size (from 5 to 20). However, there is no gain in accuracy if progeny group size available for sire evaluation is 30 or above.