Paternal Half-Sib Correlations Between Pairs in the Same and Different Herds

Correlations were computed between firstlactation milk records expressed as deviations from herd-mate averages of pairs of Holstein paternal half-sibs in the same and in different herds.These were compared to the comparable daughter-dam regressions.After correcting the daughterdam regression for environmental eom'elation and change in variance from the dam to the daughter generation, both the daughter-dam and paternal half-sib estinmtes of heritability were about .34,which suggests that maternal genetic variance is.unimportant.This estimate is, however, higher than the .25 found from the paternal halfsib estimate from an analysis for variance components.The comparison of the half-sih correlations where the pair was in the same herd (.168) and in different herds (.086) suggests that the environmental correlation among paternal half-sibs in the same herds is about .08 of the total variance.There was no evidence that this environmental correlation is less for pairs of artificially sired than for naturally sired paternal halfsisters in the same herd.