Growth progeny tests on Angus and Hereford sires under grazing conditions using supervised data collection in many herd–years

Open Access
Publisher Website
Google Scholar
Abstract
Records from the progeny of 253 Angus sires and 319 Hereford or Poll Hereford sires have been analysed using reference sires to estimate sire effects within breed for weaning and yearling weight at pasture. Each sire effect is an estimate of the expected progeny difference (EDP), or half of the sires estimated breeding value. Product-moment correlations among sire effects for Angus (Hereford and Poll Hereford in parentheses) were, for weaning weight × yearling weight 0.74 (0.75), and for post-weaning gain × yearling weight 0.80 (0.76). However, these correlations are influenced by the part-whole nature of the data. The regressions of yearling weight EPD on weaning weight EPD were 1.21 ±0.07 kg. kg 1 (1.15 ±0.08). In view of the high correlations, these regressions could be used for predicting yearling weight EPD from weaning data. The correlations between weaning weight and post-weaning gain were 0.19 (0.15). The range of EPDs was wide for both weaning weight, 18.4 kg (25.4), and yearling weight, 29.5 kg (31.6). Thus there is considerable scope for genetic selection among bulls for live weight, based on wide sampling of industry data in New Zealand.