الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Data for the present study were obtained from 2001 lactation records during the years from 2007 – 2010, at Dina Farms which lactated eighty kilometers north of Cairo, Egypt. The data were analyzed statistically using Statistical Analysis System (SAS) and results showed that:
Age of the cow, age at calving, order of lactation, stage of lactation, total milk yield, 305-day Mature Equivalent (ME), test-day milk yield, days open and season of calving, have significant effects on somatic cell score. While, dry period and number of services per conception have non-significant effects on somatic cell score.
High heritability estimates were obtained for each of total milk yield and somatic cell score. In addition, moderate heritability estimate was obtained for somatic cell count. While, other traits of low heritability such as days open.
Logarithmic production functions were highly significant with both of log SCC and log SCS. That an increasing SCC by about 2% in the milk, would decrease daily milk production and milk returns by 0.13%. Furthermore, an increasing SCS by about 2% in the milk, would decrease daily milk production and milk returns by 0.88%.