Sheep Ireland uses the central progeny test (CPT) flocks to assess the performance of sheep in a commercial setting and to validate the €uro-Star ratings.
The results of this validation work,which was carried out in 2019 and is summarised in Table 1, showed that progeny from five-star terminal rams had 4.9% less lambing difficulty, were 2.1kg heavier at 40 days of age and were 2.6kg heavier at weaning.
These findings highlight the additional gains that can be made with regard to lambing difficulty, which will reduce lamb mortality and labour, while the gains in lamb performance will reduce the days to slaughter of the lambs and reduce the overall cost of production.
When looking at the replacement index the same trend emerged with the five-star ewes outperforming their one-star counterparts.
The five-star ewes were producing 0.05 extra lambs and also had 1.2% less lamb mortality, so there was a significant increase in the number of lambs reared.
The five-star ewes were also 1.9kg lighter, on average, producing and rearing more lambs from a smaller body weight highlighting their increased efficiency.
Although the differences in each trait are small, they all combine to make a significant difference in the overall flock productivity and profitability. This validation work concluded by calculating the potential increase in profitability by using five-star genetics.
The increased number of lambs born, reduced lambing difficulty and mortality, reduced ewe mature weight and increased lamb performance all combined to give an increased flock profitability of €5 per ewe joined to the ram with five-star genetics.
€uro-Stars (in black) attached to an animal remain to be WITHIN BREED, ranking each index in 20% groupings, one star representing the bottom 20% of the breed for that trait and five stars representing the top 20%.
The higher the stars, the higher the predicted profitability from that animal within that breed.
The euro values (€2.38) of each trait and index can be compared ACROSS BREEDS, which allows any two rams to be compared to each other regardless of breed.