Selection for Rate of Gain, Appetite and Efficiency of Feed Utilization in Mice

Estimates of genetic parameters and selection strategies to improve the economic efficiency of postweaning growth in lambs1

“…Arthur et al (2001b) reported a genetic correlation of −0.10 between ADG and residual feed for Charolais bulls. For mice, realized genetic correlations of postweaning ADG with feed intake and feed conversion ratio after 22 generations of selection were reported to be large (0.88 and 0.91; Sutherland et al, 1970).…”

“…Selection for rate of gain will generally increase mature size of ewes (Brown et al, 1987), cows (Brinks et al, 1964), and rats (Sutherland et al, 1970). For sheep, increasing ewe mature size has been shown to improve milk production, result in a leaner carcass at a given slaughter weight (Brown et al, 1987), and improve ewe reproductive rate (Ercanbrack and Knight, 1998).…”

Renewed selection for heat loss in mice: Direct responses and correlated responses in feed intake, body weight, litter size, and conception rate1

“…The difference in body fat between the MH and MC mice amounts to over 1.0 g. Thus, part of the smaller BW of the MH mice is due to indirect selection responses in body fatness. Sutherland et al (1970) found that mouse lines that were previously selected for greater efficiency of gain (gain:feed ratio) had greater rates of gain than lines selected solely on greater feed intake. They also showed that rate of gain had a high positive correlation (0.91 ± 0.04) with gain:feed ratio.…”

“…They observed heritability estimates of 0.17 ± 0.04 for the overall gain:feed ratio estimate and 0.20 ± 0.06 for feed intake. Comparison of results between Sutherland et al (1970) and this study are difficult due to differences in traits measured.…”

“…Bishop and Hill (1985) and Selman et al (2001) confirmed these results by conducting related studies with the same lines of mice in Scotland. Sutherland et al (1970) selected mice on increased efficiency of feed usage (gain/feed), increased feed intake, and increased rate of gain. They observed heritability estimates of 0.17 ± 0.04 for the overall gain:feed ratio estimate and 0.20 ± 0.06 for feed intake.…”