Introducing easy-care terminal sires to help reduce labour costs for sheep flocks in Northern Ireland hit lamb carcass quality, but this was more than compensated for by extra income generated by improved lamb output, new research suggests.
Continued pressure on flock margins in the province has led to a focus on labour as an area where many producers could claw back costs, particularly at lambing, suggests Ronald Annett, sheep production scientist at the Hillsborough-based Agri-Food and Biosciences Institute (AFBI).
During 2006 AFBI trials looked at the effect of introducing easier care New Zealand x United Kingdom Suffolk terminal sires.
“The most notable difference from these sires was the reduced need to help ewes at lambing 81% lambed unassisted compared to 64% of ewes put to a UK Suffolk sire,” says Dr Annett.
There were other plus points to using easy-care rams. “What we hadn’t anticipated was an apparent improvement in fertility of ewes mated to the NZ x UK Suffolk with an increase of 0.23 lambs born a ewe and 0.19 lambs weaned a ewe.
“We are carrying out further trials this year to establish whether this is a genuine ram effect,” he says.
Growth rates between sire groups were similar through to slaughter. However, there were significant differences in carcass quality defined by the EUROP grading grid.
“Almost 40% of the UK Suffolk-sired rams achieved an E or U grade compared with 17% for the easy-care sires. The proportion hitting E, U and R grades was 98% and 90%, respectively. Carcass fat class was similar across both groups with 93% hitting the target of Class 2 or 3” (see table below).
Using a price of 230p a kg for a target R3 carcass, a 10p a kg bonus for U grade and a 10p a kg penalty for O Grade carcasses, UK Suffolk-sired lambs were worth £0.61 a head more at slaughter.
“That said, the increased lambing percentage for the easy-care-sired lambs generated an extra £7.43 a ewe, outweighing the lower carcass value,” says Dr Annett.
“For years now the message sent to producers has been to improve carcass quality. But the largest demand driven by multiple retailers is for R3 carcasses which in most cases makes the bonus for achieving a higher quality lamb relatively small compared with potential increases in output a hectare or output a ewe generated by improved fertility.”
For those producers paid a significant bonus for producing E and U Grade carcasses the financial impact will be less, admits Dr Annett. “Again, it depends on which market you’re serving and what you’re being paid.”
Producers must also consider the impact long-term use of easy-care terminal sires may have on carcass quality. “Of course, there is a balance to be struck between quantity and quality of lamb output it would be disastrous to move the sector from one extreme to another,” adds Dr Annett.
“However, the research clearly demonstrates there is scope to achieve significant labour savings at lambing by using easier care sires while meeting market spec in terms of quality.”