تقدير المعالم الوراثية و اللاوراثية لبعض صفات النمو لعجلات الهولشتاين

Abstract EN

This study included 2358 records of growth traits of heifers, over the period from 1997 to 2000, ax al-Naser Dairy Station, united livestock Co.Ltd.

Al-Soweira (50 km south Baghdad) , the station had a herd of Holstien cows.

The study was conducted to estimate the genetic parameters after adjusting the effect of fixed factors.

General linear model (GLM) and SAS program was used to study the effect of fixed factors, parity, season and year of parturition on berth weight (BW), gain body weight GBW from birth to weaning , (GBW) from birth to yearling and GBW from weaning to yearling (GWY)_Restricted Maximum Likelihood (REML) was conducted to estimate variance of components of random effects supposing Mixed model.

The overall means of BW, GBW, GBY, GWY, were 34.96 kg, 0.500 kg / day, 0.755 kg / day and 0.781 kg / day respectively .

Parity , season, and year of parturition had significant effects (P < 0.01) on BW, GBW, GBY, and GWY.

Heritabilitv of BW, weaning weight, yearling weight , GBW, and weaning weight were 0.17, 0.33, 0.29, 0.15, and 0.09 respectively.

Highest genetic and phenotypic correlation were exited between weaning and yearling weight.

(0.91) and (0.94) respectively.