الفهرس 
Calving intervalsOnly 14 pages are availabe for public view
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Abstract
Records 3067 from 751 cows representing the period from 1969 to 1982 at Sakha, El-Karada Exp. Station were analyzed t o document e f f e c t s of milk production i n the 8-th, 1 6-t h and 242 week p o s t parturn on r eproduc t ive performance of Friesian cows, f i v e measures r e l a t e d t o breeding efficiency were used: first service after calving, number of services required f o r conception, days open, calving i n t e r v a l s and breeding efficiency on a terms of calving i n t e r v a l and longevity i n terms of number of partu r i t i o n were studied.it was found It was found from the present study t h a t : 1- The average i n t e r v a l from calving t o f i r s t service , number of services per conception, days-open calving i n t e r v a l and breeding efficiency are: 102.31f;73.56,2.02~ 1.32, 167.92+120.73, 445.3+120.02, and 84,3~15.56, respectively. 2- I n t e r v a l from calving to first service correlated negat i v e l y with milk production i n 8%, 16th and 242 week with -0.05, -0.01 and -0.03, respectively. The correlations were not s i g n i f i c a n t . The regression of first service i n milk production was not s i g n i f i c a n t . Season . of calving had no s i g n i f i c a n t e f f e c t on first service, however the p a r i t y of cows bad s i g n i f i c a n t (P ( 0.05 ) e f f e c t on f i r s t service.