Investigating the potential for finishing of hill lambs to carcass weights of 12-16kg
Teagasc Researchers, Frank Campion & Michael Diskin, take a look at finishing hill-bred lambs at lighter carcass weights following short-term ad-lib concentrate feeding under good management.
Introduction
Previous research carried out in Teagasc Athenry has shown the potential to finish hill bred male lambs to carcass weighs in excess of 18 kg while meeting market muscle and fat score specifications satisfactorily (Claffey et al., 2018). These authors also demonstrated that hill bred lambs were highly responsive to improved nutrition post-weaning. Recently, these studies have begun looking further into finishing lambs to comparatively lighter carcass weights following short-term ad-lib concentrate feeding. As with any intensive finishing system this requires good flock management to keep mortality rates low and ensure lambs are drafted at the correct weight to avoid selling lambs that are too light or don’t have sufficient muscle and fat cover to meet market specifications.
‘Light lamb finishing’
The studies were under taken in Teagasc Athenry to ascertain if it was possible to finish light Scottish blackface lambs to produce carcasses of 12-16 kg with a suitable covering of fat. The performance of these lambs on these studies is summarised in Table 1.
Lambs were housed after weaning at an average live weight of 25 kg and slowly built up to ad-lib concentrate intake. Both wether and ram lambs were used and were drafted for slaughter once they reached 30 kg live weight for wethers and over 31kg live weight for ram lambs and had a level of fat cover equivalents to fat score 2 post slaughter. Where lambs, particularly ram lambs, reached 36 kg live weight and were deemed “unfinished” then they were retained and finished to ‘French’ market specification (>18kg carcass weight).
Proper selection of lambs for slaughter is essential with this system and lambs need to be weighed regularly to avoid lambs falling out of specification for the ‘light’ lamb trade and still being under finished for ‘French’ specification markets. Where lambs are too heavy for the ‘light’ lamb market or reach the correct live weight but have insufficient fat cover to market specifications then it is necessary to carry these lambs to a minimum of 42 kg to finish for the ‘French’ specification market. In our studies approximately 15% of the lambs initially housed to finish as ‘light’ lambs were sent for ‘French’ market specification, showing the importance of regular live weighing and handling of the lambs. During the finishing period lambs consumed approximately 1.15 kg DM of concentrates per head per day once eating concentrates ad-lib.
Picture 1. On the left a 14.6 R2 carcass slaughtered at 33.5 kg live weight and on the right a 15.7 kg R2 carcass slaughtered at 34.5kg live weight.
Research in practice
The results of this research have been positively received by hill farmers with groups visiting Teagasc Athenry regularly to see the research, discuss the results and see how to correctly identify lambs finished to the market specification. One such group that has visited and has been suppliers of the Atlantic Hill Lamb brand which was started in recent years and is an initiative supported by the INHFA, Bord Bia and Kepak. This brand is sourcing ‘light’ lambs from hill farms that meet market specifications of 10-15kg carcass weight with a minimum carcass confirmation of “O” and fat class of 2 or better. While still in its early stages, the initiative is being enthusiastically received by farmers who see the potential to finish some of their own light lambs on farm rather than relying totally on the store lamb trade. Last year the group supplied in the region of 20,000 lambs to this market and are hopeful this can be expanded in the future.
Picture 2. It is important that lambs are the appropriate weight and have adequate muscle and fat cover to meet the specifications for the light lamb trade.
Conclusion
There is potential to finish hill bred male lambs at lighter carcass weights while meeting market specifications for muscle and fat cover. However, markets are somewhat limited for these carcasses so it is important to have a contract for these type lambs and careful selection of lambs for slaughter is essential to ensure carcasses meet minimum specification for payment. Future research into finishing lighter hill lambs aims to look further into the effect of diet and breed type for these finishing systems.