الفهرس 
Main fixed effects
Genetic parametersOnly 14 pages are availabe for public view
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Abstract
A total of 1018 standard lactating of Friesian cows, progeny of 54 sires and
432 dams kept at Sakka Experimental farm, during 2012 to 2017 are used to
calculate phenotypic and genetic effects for milk production in tenth months(MP), lactation length(LL) and fat percent(F%).Four selection indexes are calculated using relative economic weights (REW), method 1, one phenotypic
standard deviation (REW1) and method 2, Lamont method (REW2).The overall
means of MP, LL and Fat % are 3879 kg,301 d and 3.69%, respectively. Month,year of parturition and lactation order had significant(P<0.01)effects on all studied traits, except month of parturition and lactation order effects (P>0.05)on F%. Bulls and cow within bulls had significant(P<0.01)effects on all traits studied. Heritability estimates are 0.32, 0.10 and 0.55 for MP, LL and Fat %,respectively. Genetic correlations among three variables are significant and ranged from 0.21 to 1.00. The basic index (Index1), which includes the three variables MY, LL and Fat % was the best (had the highest accuracy(RIH) and relative efficiency values(RIH was 0.87 and 0.88 for REW1 and REW2,respectively).