To provide a replicate that could be used to verify any correlated responses to selection, we initiated a second line. The HDID-2 line was selected in the same way, for the same trait. The only exception was that we started the HDID-1 selection using a rotational breeding scheme (Halcomb et al. 1975), and then to accelerate the rate of response, we shifted to individual selection after 5 generations. The HDID-2 line was subjected to individual selection throughout. Figure 2 shows the response to selection in both replicates. The HDID-2 selection response appears to resemble the response in HDID-1 very closely. For example, the S7 HDID-2 mean BEC was 0.55 ± 0.04 mg/ml, and the S7 HDID-1 mean was 0.64 ± 0.04 mg/ml. In both lines, the animals achieved higher BECs by ingesting more alcohol. Although selection was based only on BEC and not on intake, the intakes have increased as a genetically correlated response to selection (Fig. 3). The S7 HDID-2 mean ethanol intake was 6.45 ± 0.33 g/kg, while that for the S7 HDID-1 mean was 5.89 ± 0.26
