الفهرس 
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Abstract
The aims of this study were :1- to estimate the non-genetic factors affecting milk production traits of friesian such as maximum milk yield,305 day milk yield, total milk yield,total life time milk yield,total location period and longevity traits such as age at disposal and number of loctations completed.2-to estimate phenotypic and genetic parameters of these traits.3-to study the relationships between age at first calving and first loctation milk yield and each of lifetime production and longevity traits.