Progeny performance of industry and index selected Angus bulls.
R.M. Enns and G.B. Nicoll
Landcorp Farming Ltd, PO Box 1235, Hamilton.
Proceedings of the New Zealand Society of Animal Production. 1997,
57: 12-14
The Department of Lands and Survey (LS) introduced an
objective-based, open nucleus Angus breeding programme in 1976 to
produce bulls for its commercial properties. Previously, commercial
sires were purchased from numerous industry sources (IND). To determine
performance differences between the two sire sources, 600 mature Angus
cows and heifer replacements were randomly mated to either LS or IND
bulls beginning in 1976. Replacement female offspring from these matings
were then randomly mated to either LS or IND bulls to produce second
generation offspring (GEN2). Herd size was maintained and matings
continued through 1986. Growth performance of all GEN2 animals was
recorded through weaning. After weaning, only female performance was
recorded. Least-squares methodology was used to determine differences
between the two genetic sources (IND or LS). Traits measured were
weaning weight (WW); cow ratio (CR; calf weaning weight per 100 kg of
cow weight); yearling weight (YW); and 18 month weight (18M). The
statistical model for all traits included year of birth (YOB), sire
source of calf (CSS) and dam (DSS), sex (where applicable), age of dam
(AOD), age at weighing, and the interactions of YOB and CSS, YOB and
DSS, AOD and CSS, AOD and DSS, and CSS and DSS. Calf’s sire source was
significant (P<0.01) for WW and CR, and approached significance for YW
(P<0.10) but was not significant for 18M (P >0.10). Neither dam's sire
source nor the interaction of CSS with DSS was significant for any trait
(P>0.10). The WW of progeny with LS maternal grandsires and LS sires was
4.6±1.7 kg greater than progeny with IND sires and IND maternal
grandsires (P<0.01). Differences in weights taken subsequently were
smaller (P>0.10). Although not statistically important, in a production
scenario where all male progeny were sold at weaning, benefits of the
introduction of an objective-based, breeding scheme were evident.
Keywords: NZSAPAB;
Beef cattle; Angus; sire source; index selection; liveweights.
Last Updated 12-09-1998
