Genetic evaluation of sires according to days open of their daughters in two herds of Holstein cows in the middle of Iraq
journal of kerbala university,
2007, Volume 3, Issue 4, Pages 11-15
AbstractA total of 2718 records of days open belonged to Holstein cows in two herds , Nasr and Esehaqi dairy cattle over period from 1997 to 2001 were analyzed . The aim is to evaluated sires genetically according to days open of their daughters after adjusting for fixed effects and to estimate heritability. General Linear Model (GLM) within the SAS program 2001 was used to study the effect of some fixed effects ( level of first milk yield , season and year of calving , parity , age at first calving and herd ) in days open. Component of variance for the random effects in the employed mixed model were estimated by REML method. The Harvey program was also used to estimate BLUP values for 29 sires. The overall mean of days open was 133.46 days and the effect of all fixed factors was significantl (P < 0.01) except season of calving which was significant ( P < 0.05 ) and age at first calving was not significant. The heritability of days open being 0.04.
Best linear unbiased estimation for 29 sires ranged from – 30.00 to 26.31 days.
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