Asymmetric genetic correlations between dairy traits

Realized genetic correlations between dairy traits were estimated from halfsib response to (a) upward, respectively downward selection and (b) to different selected traits. Data comprised records from 36 870 Bavarian Fleckvieh and from 9434 Angler cows from the years 1977-88 and 1990, respectively. No asymmetry appeared between upward and downward selection. However, in both breeds selection for yield led to stronger negative reaction in fat and protein content than vice versa. Between protein and fat content the realized correlation appears to be symmetric.