This year we classed our 2008 “full-blood” Dorper & White Dorper ram lambs and the bottom 30% of that group were sent to slaughter at WAMMCo abattoir, Western Australia.
WAMMCo utilises the Viascan technology and has now commenced a bonus scheme (WAMMCo select) for animals that meet a high “loin and leg yield”. To qualify for the bonus a lamb must be in the top 15% of lambs processed based on their pedicted lean meat yield (LMY) for the combined leg & loin readings.
For 18.1-22kg carcase – LMY > 33.5%
For 22.1+ carcases – LMY >32.6%
47% of Dorper lambs, in the correct weight range, made the selection criteria and recieved the bonus whereas only 22% of the White Dorper lambs made the selection criteria.
The lambs were run on oaten stubble and were introduced to a feedlot for 9 days utilising Milne Feeds “Easy1” pellets.
We compared Dorpers and White Dorpers in the table below.
| Dorper | White Dorper | Diff | Total | |
| Number | 101 | 49 | 150 | |
| Net hot weight | 22.84kgs | 21.38kgs | 1.46kgs | 22.36kgs |
| Fat score | 2.16 | 2.22 | 0.06 | 2.18 |
| via leg yield | 22.51% | 22.28% | 0.23% | 22.44% |
| via loin yield | 10.27% | 10.03% | 0.14% | 10.19% |
| via shoulder yield | 17.55% | 17.36% | 0.19% | 17.49% |
| via carcase yield | 50.33% | 49.68% | 0.65% | 50.12% |
| live weight | 48.85kgs | 47.05kgs | 1.8kgs | 48.26 |
| Dressing % | 46.80% | 45.49% | 1.31% | 46.37% |
| Average age | 270 days | 265 days | 5 days | |
| Bonus lambs 18.1-22kgs | 18/35 (51%) | 6/28 (21%) | ||
| Bonus lambs 22.1+kgs | 28/62 (45%) | 4/18 (22%) | ||
| Lambs less than 18.1kgs | 4 | 3 | ||
When analysing the carcase yields, a difference of 0.65% on a 22.36 kg carcase results in 0.1453kgs of meat @ $17/kg or $2.47 per carcase for the processor.
We also compared the weights vs. the fat score to show that we are able to take a purebred Dorper & White Dorper ram lamb to a heavyweight carcase under grazing conditions and with limited feedlotting
| Weight range | Score 4 | Score 3 | Score 2 | Score 1 | Total |
| 16.1-18 kgs | 7 (4.7%) | 7 (4.7%) | |||
| 18.1-20kgs | 23 (15.3%) | 23 (15.3%) | |||
| 20.1-22kgs | 3 (2.0%) | 36 (24.0%) | 1 (0.7%) | 40 (26.7%) | |
| 22.1-24kgs | 7 (4.7%) | 31 (20.7%) | 38 (25.3%) | ||
| 24.1-26kgs | 10 (6.7%) | 19 (12.7%) | 19 (12.7%) | ||
| 26.1-28kgs | 4 (2.7%) | 5 (3.3%) | 9 (6.0%) | ||
| 28kgs | 1 (0.7%) | 2 (1.3%) | 1 (0.7%) | 4 (2.7%) | |
| Total | 1 (0.7%) | 26 (17.3%) | 122 (81.3%) | 1 (0.7%) | 150 (100%) |