Heifer Fertility Relationship with First Lactation Cow Traits of Friesian Dairy Cattle in Egypt

Relationships were estimated between heifer fertility traits with first lactation traits of Friesian cows in Egypt. Data of 2914 calved animals covering the period from 1979 to 2013 in Saka and Elkarada stations were obtained. Multi-traits linear animal model was applied. The highest absolute genetic correlations were obtained between NSC0 and CR1 (0.827), between CR0 and CR1 (-0.763), between SP0 and NSC1(-0.793), and between each of AFB and AFC with CFS1 (-0.728 and -0.739). All phenotypic relationships between heifer and first lactation fertility traits were small and near to zero. Genetic relationships between fertility traits of heifers and first lactation cows were ranged from -0.999 to 0.999. The highest genetic correlations were obtained between DMY1 and each of NSC0, CR0 and SP0 (0.999, -0.999 and 0.997, respectively), between M305 with the same traits (-0.996, 0.997, -0.989, respectively) and between TMY1 with NSC0, CR0, SP0, AFB, ASB and AFC (-0.984, -0.984, 0.975, -0.998, -0.973, -0.984, respectively). All phenotypic relationships between fertility traits of heifers and first lactation cows were smaller than that of genetic correlations except between TMY1 and each of NSC0 and SP0 (-0.969 and 0.970).