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

J. M. McDonald, M. K. Nielsen

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Divergent selection in mice was renewed in 3 independent replicates for high (MH) and low (ML) heat loss. An unselected control (MC) was maintained in all replicates. Heat loss was measured for individual male mice for 15 h, overnight in direct calorimeters. After 16 initial generations of selection followed by 26 generations of relaxed selection, divergent selection resumed for 9 generations. The realized selection applied was very close to the maximum possible selection according to the criteria and protocol. Selection differentials were greater for high than for low selection due to greater variation in the MH line. When corrected for SD, standardized selection differentials were similar for MH and ML selection. Unintended selection in MC was negligible. Realized heritability for divergence was 0.14 ± 0.01, which was considerably less than that realized during the initial generations of selection (0.28 ± 0.03). Realized heritabilities for MH selection (0.16 ± 0.05) and for ML selection (0.07 ± 0.06) were less, especially for ML selection, than were observed in the earlier generations. The difference in heat loss between MH and ML males was 55.7% of the MC mean at generation 51, compared with a difference of 53.6% in generation 15; this difference had decreased to 34.4% at the end of the relaxed selection (generation 42). For feed intake between 8 and 11 wk, MH and ML males differed by 34.0% of the MC mean by the end of the selection process. Body weight at 12 wk for MH and ML males was less than for MC males. Litter size response was positively related to the heat loss response. Conception rate was poorer in MH matings than in MC and ML matings.

Original languageEnglish (US)
Pages (from-to)658-666
Number of pages9
JournalJournal of animal science
Volume85
Issue number3
DOIs
StatePublished - Mar 1 2007

Fingerprint

Litter Size
correlated responses
conception rate
litter size
feed intake
Hot Temperature
Body Weight
heat
body weight
mice
heritability
calorimeters

Keywords

  • Conception rate
  • Feed intake
  • Heat loss
  • Litter size
  • Mice
  • Renewed selection

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology
  • Genetics

Cite this

Renewed selection for heat loss in mice : Direct responses and correlated responses in feed intake, body weight, litter size, and conception rate. / McDonald, J. M.; Nielsen, M. K.

In: Journal of animal science, Vol. 85, No. 3, 01.03.2007, p. 658-666.

Research output: Contribution to journalArticle

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