This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Holt, M Articles by Farstad, W Search for Related Content PubMed PubMed Citation Articles by Holt, M Articles by Farstad, W

Components of litter size in mice after 110 generations of selection

Department of Animal and Aquacultural Sciences, Agricultural University of Norway, PO Box 5025, 1432 Ås, Norway and ¹ Department of Production Animal Clinical Sciences, The Norwegian School of Veterinary Science, PO Box 8146 Dep, 0033 Oslo, Norway

Correspondence should be addressed to M Holt; Email: marte.holt{at}iha.nlh.no

The aim of the present study was to evaluate how ovulation rate and survival rate through pregnancy had been affected by more than 110 generations of upwards selection on litter size in mice. The mean number of pups born alive was 22 in the high line (selected line) and 11 in the control line (an increase in 2.6 standard deviations). Selection on litter size increased ovulation rate by 4.6 standard deviations, and it is suggested that selection also increased embryonic mortality in late pregnancy. Embryo survival from ovulation until birth was 66% in the selected line and 69% in the control line, and the observed loss in litter size from day 16 of pregnancy until birth was possibly higher in the high line compared with the control line. Selection for higher litter size has significantly increased body weight in both males and females, as the mean weight at mating for the females was 46 g in the high line and 33 g in the control line respectively.