Genetic study on some productive and reproductive traits using records primiparous friesian cows in Egypt [electronic resource].

Includes references.

A total number of 1927 first lactation records of Friesian cows sired by 146 bulls and collected from Sakha Farm, Ministry of Agriculture, Egypt covering 31 years from 1968 to 1999 were used in this study. Genetic parameters and breeding values for productive and reproductive traits were analyzed using multiple-trait animal model analysis of total jointly with some reproductive traits;e.g., age at first calving (AFC, month), days open (DO, day) and number services per conception (NSPC, service). Unadjusted means of TMY, AFC, DO and NSPC were 3651 kg, 31.7 month, 204.2 day and 2.1 service, respectively Estimates of heritability for such traits were 0.21±0.17, 0.25±0.39, 0.06±0.07 and 0.14±0.21, respectively. The genetic and phenotypic correlations between TMy and the reproductive traits as well as between the reproductive traits studied revealed positive highly significant values (p<0.01). The genetic correlation between TMY with AFC, DO and NSPC were 0.39±0.91, 0.42±0.87 and 0.91±0.18, between AFC with DO and NSPC were 0.92±0.28 and 0.42tO.98, and between DO with NSPC was 0.90tO.68,respectively. The phenotypic correlations between TMY with AFC,DO and NSPC were 0.09, 0.32 and 0.09, respectivelY,and between AFC with DO and NSPC were 0.09 and 0.37, respectively and DO with NSPC was 0.33. The range of breeding values obtained from mUltiple-trait analysis of all pedigree animals for TMY, AFC, DO and NSPC were 5297.10 kg, 4.90 month, 15.03 day and 1.83 service.

Summary in Arabic.

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