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Fig. 1. Daily energy expenditure (DEE) as a function of body mass for
lactating (filled circles, N=24) and non-reproductive (open circles,
N=17) female mice exposed to 30°C. DEE was measured when
the reproductive females were at day 14 of lactation. Body mass is the mean
value for days 913 of lactation (reproductive females) or the mean
value for eight consecutive days before the day of doubly labelled water (DLW)
injection (non-reproductive females). The relationship for lactating females
is described by y=28.18+2.58x; the relationship for
non-reproductive females failed to reach significance.