Date of this Version
The average first lactation milk yield of crossbreds in northern region was higher than that in southern region with heritability estimates being 0.16±0.06 and 0.04 ± 0.04. The heritability estimates according to production level were 0.28 ± 0.14, -0.02 ± 0.04 and 0.36 ± 0.15 for low, medium and high level herds in northern and -0.05 ± 0.01 and 0.03 ± 0.12 for low and high level herds in southern region,suggesting more genetic viability in relation to total variance in high level herds. The reasons for low estimates in medium level herds have been discussed. The sire x genetic group interaction was estimated from (i) two way analysis of variance" and (ii) genetic correlation between the same trait expressed in two genetic groups. The sire x genetic group interactions were non-significant and the genetic correlations were 0.87 and 1.00 in northern and southern region, respectively. The sire x breed of dam interaction was non-significant for all breed group combinations.