Consistent age differences at around 27 kg live weight have been found between control (C) and selection (S) line boars of the Large White breed in a coordinated breed improvement programme (89·8 v. 94·6 days, P<001). After 10 generations of index selection on feeding ad libitum, a sample of 20 boars from the programme, 10 C and 10 S, were slaughtered at 27·6 (s.e. 0·48) kg live weight for a more comprehensive examination of this finding. Physical dissection of the carcass and whole body chemical analysis were carried out. Differences between C and S boars were apparent even at this light weight: S boars were older than C (92·7 v. 83·5 days, P<0·01), contained less dissected fat (2·93 v. 3·58kg, P<005) and chemical lipid (315 v. 3·59kg, P<0·05), and had a higher lean proportion (0·477 v. 0·458, P<0·01). There was no significant difference between lines in weight of dissected lean or whole body protein. Index selection has clearly affected early growth and body composition, which questions current assumptions underlying pig testing methods.
ASJC Scopus subject areas
- Animal Science and Zoology