The Sustainable Lamb Project (SLP) aimed to combine advances in sheep breeding with strategic use of different grassland types.
One of the main focuses was on grazing less improved areas with breeding ewes, while another part of the project examined the benefits and limitations of delaying lambing dates.
SLP involved one of the Ibers University farm flocks, five commercial farmers throughout the country, and industry partners, Innovis and Dalehead. The project received support through the RDP for Wales 2007-2013 which was funded by the Welsh Government and the European Agricultural Fund for Rural Development.
Delaying lambing date offers a range of benefits and limitations. Its main aim is to reduce reliance on concentrate feed for ewes over the lambing period.
However, late lambing is often constrained by a lack of suitable low-cost quality forage for flushing to achieve viable lambing percentages in standard commercial sheep breeds, says manager of the Ibers Grassland Development Centre, Dr Heather McCalman, who worked on the project.
The study investigated if using a more prolific Aberdale ewe, which requires a maintenance only plane of nutrition before tupping, known as non-flushing, can help overcome this constraint.
The study, carried out at one of the Ibers university farms, compared two lambing systems using Aberdale compared to a cross-bred control. About 80 ewes of each breed type featured in each system, one March and the other mainly outdoor May lambing, with tupping during December.
All ewes in each system were kept as one group, except for the four weeks before, during, and four weeks after tupping, when ewes were managed according to their specific nutritional requirements.
Dr McCalman says: “Average scanning percentages were lower on the May lambing system at 183 per cent, compared with March lambing at 210 per cent, and were, on average, higher in Aberdale ewes at 213 per cent, compared with control cross-bred ewes at 180 per cent. Lamb birth weights on the May lambing system were on average 0.86kg heavier than those born in March.
“However, in terms of overall performance, the liveweight gains and final carcase weights of lambs born in the March lambing system were the highest.”
Making best use of grassland to maximise output and overall economic performance was investigated on the five commercial farms putting Aberdales to the test with a traditional breed type.
These units worked with Ibers Grassland Development Centre and the Farm Business Survey to monitor their sheep systems from tupping to slaughter.
The flocks lambed between March and April, and monitoring included ewe liveweight and condition pre- and post-tupping, grassland quality at key times and scanning percentages.
Pastures grazed by Aberdale ewes contained a lower proportion of rye-grass and a higher proportion of secondary species and were of lower nutritional quality.
Scanning percentages of the Aberdales were higher on all farms - a minimum 202 per cent, compared with the others at 159 to 169 per cent.
Dr McCalman says: “Those farmers who had more experience of Aberdales managed ewe body condition and controlled scanning percentage to target by strategic management of grassland quality and availability, from pre- to post-tupping, according to ewe type.
“The Aberdale ewes were able to use poorer quality pasture on marginal land and maintain productivity over the tupping period without flushing.
“They gave farmers the opportunity to release their better quality land for finishing lambs from the previous season.”
The Griffith family’s farm, located on the Llyn peninsular, is one of SLP’s five commercial units.
It has demonstrated that on marginal land, output on poor quality grazing can be improved by 25 to 30 per cent by replacing a traditional flock of Welsh Mountain ewes with Aberdales.
“We are focused on maximising kilos of finished lamb per ewe, yet our traditional Welsh Mountain flock which we ran at Cefn Isa was scanning at just 150 per cent,” says Ellis Griffith, who farms with his parents Edward and Jackie. “While we wanted to step up output, stocking more sheep was not an option - neither was making significant improvements to grazing quality.
“We had read Aberdales were relatively small, hardy ewes which could potentially rear a high number of lambs on poorer pastures. We initially purchased ewe lambs in 2010 and, in view of their subsequent performance, we have now replaced all of our Welsh Mountain ewes with Aberdales (see table).”
|Damline: Welsh Mountain||Damline: Aberdale|
|Ave DLG or days to finishing||110||120|
|Ave output (kg/ewe dead weight.||25||32|
“After weaning at the end of July, we move the ewes to the poorest ground on-farm. They remain there throughout the pre-tupping and tupping periods until the end of November.
“During that time they are stocked at an average 10 ewes per acre and we monitor their condition score, setting a target score of 3 throughout the flock.
“Tighter stocking means we now have more than 60 acres available for lamb finishing and some deferred grazing for the ewes later on in the season.”
The Griffith family use Abermax sires and the entire crop of lambs is finished to average 18kg deadweight.
All ewes grade either R or U and hit the specification required by their buyer.