By James Garner
TURNING early lambing ewes and lambs out five to six weeks after birth leads to higher flock profitability than early weaning and intensive finishing, but the risk of failure is greater, according to Irish researchers.
Results comparing both systems at Knockbeg Sheep Unit, Carlow, Co Carlow, Republic of Ireland, suggest that profits may be higher when turning lambs out to pasture. But weather induced problems can cause lamb thrift to suffer, warns Teagasc sheep production officer and farms director Sean Flanagan.
"The grazing option is more profitable because it is cheaper to finish lambs off grass. But a wet spring can cause problems and be difficult to manage.
"However, early weaning and finishing lambs indoors offers control over lamb feed intakes and allows an accurate prediction of lamb performance. This is important because we want lambs to finish at 18kg carcass weight in 100 days; to achieve this, control is necessary."
Choosing to turn ewes and lambs out means weather or poor lamb thrift can hold up performance, leading to lambs missing the target and the market, he adds.
Irish sheep producers can still sell into an Easter market running through to mid-May, when main season lambs begin finishing. And unlike the UK, three-quarters of lamb produced is exported. This means early season lamb, despite concerns over profitability, is still essential to Irish lamb production because it provides the continuity of supply required by its customers, says Mr Flanagan.
However, early lambing profitability concerns have raised questions about intensive systems requiring high inputs. "But it is possible to cut lamb intakes and costs by using a home-mix to replace compound creep".
This consists of 40% barley, 40% sugar beet pulp and 20% soya bean meal. Research at Knockbeg using this ration, costing £112/t, found lamb finishing costs can be cut by £6.90/head compared with a compound ration.
But offering creep to lambs within a week of birth improves the success rate where ewes and lambs are turned out to grass after five weeks.
"Ample grass supply must also be on offer. When its not, there is no alternative but to early wean and finish lambs inside," he says.
Ensuring grass is available for early lambers means nitrogen has to be applied in mid-February. After turn-out, management difficulties occur when its too wet to graze, meaning ewes and lambs must be moved regularly to stop poaching and disease risks.
But one phenomenon from finishing lambs off grass remains a mystery. "Lambs finished off grass have heavier carcass weights – up to 1kg more – than indoor finished lambs, and theres no difference in fat levels when these lambs have been scanned."
"It is possible that lambs at grass exercise more and so have better muscle development. They also eat grass, which may have an effect, and they may receive bypass protein from ewes milk." *