Study on Friesian Herds Raised in Egypt and Germany – I. Estimate of non-genetic effects and genetic parameters
Abstract. Data on 2422 and 27756 Friesian cows in Egypt and Germany, respectively, were used to estimate genetic and non-genetic effects on initial milk yield in 70 days (IMY), 305-day milk yield (305-dMY), lactation period (LP) and calving interval (CI). Data were collected in the period from 1987 to 1992 in Egypt and from 1979 to 1993 in Germany. Least Squares analysis shows the significant effect of season and year of calving and parity on all traits. Least Squares analysis indicates that winter and spring calvers had the higher value in all traits studied than summer and autumn calvers of Friesian cows in Egypt, while in German Friesian cows, the autumn calvers had the higher value in all traits studied than summer and spring calvers. The results show that the milk yield increased with increased lactation Orders. Partial linear and quadratic regression coefficients indicate that age at calving was negatively associated with CI, while it showed positive association with LP and 305-dMY in Friesian cows in Egypt, while in German Friesian cows age at calving was negatively associated with LP and CI, while associated positively with milk yield. Heritabilities were 0.24, 0.22, 0.14 and 0.16 for IMY, 305-dMY, LP and CI, respectively of Friesian cows in Egypt and were 0.34, 0.24, 0.08 and 0.09 for IMY, 305-dMY, LP and CI, respectively in German Friesian cows. All phenotypic and genetic correlations between different traits studied were positive and significant.