Genome-wide interaction analyses of milk production traits in dairy cattle

Abstract

Figure 1.2. Genetic correlations of milk yield at different lactation stages and fat content at different lactation stages. Data are adapted from Druet et al. (2005). Genetic correlations of milk yield and fat content during lactation is shown in Figure 1.2. It shows that genetic correlations between test-day milk yield measured between day 20 till day 150 in lactation are higher than 0.8. Genetic correlations between fat content measured from day 20 till day 230 in lactation are higher than 0.8. The genetic correlations decrease when the time interval between lactation stages increases, e.g., the correlation between milk yield at day 20 and day 320 is smaller than 0.2. Similar results were found in other studies (