Independent sheep adviser, Kev Bevan has been involved in the development of the Upland Farmer Toolkit, an online tool to help producers evaluate their businesses and identify potential areas for change. He outlined how ewe efficiency is calculated and offered some pointers on how to improve productivity.
Ewe efficiency is a useful indicator of flock output and it is an important element of the Upland Farmer Toolkit, said Mr Bevan, who explained how the figure is calculated.
“The online calculator will work out ewe efficiency from individual farm data,” he said. “The figure is a measurement of the weight of lambs weaned in relation to the weight of ewes tupped. One example is a crossbred flock that has produced 1,500 lambs with an average weaning weight of 30kgs. Assuming that 1,000 ewes weighing an average 90kgs went to the tup, the ewe efficiency figure would be 50 per cent.
Kev Bevan, independent sheep adviser – Picture: Chris Watt
“While lambing percentages tend to be lower for hill flocks the ewes tend to be lighter, which partially compensates the calculation.”
After working out the on-farm figure, the next step is to establish whether the results reflect good, average or poor flock performance. For crossbred-type flocks he suggested that 50 per cent or lower would indicate performance worthy of further investigation, with a result between 51-60 per cent moderate, 61-70 per cent considered good and 70-plus per cent excellent.
“One common reason for a low ewe efficiency score is poor lamb growth rate,” he explained. “Flocks may be lambed too early, with turnout on to inadequate pasture. It is essential to monitor ewe body condition scores throughout the year, so that ewes are in good condition and can produce plenty of milk for their lambs.
“Pastures must be carefully managed to ensure plenty of quality feed. While lamb growth rates are largely dependent on the dam for the first couple of months of life, thereafter lambs will need plenty of leafy pasture to grow strongly.
Flock of Suffolk cross sheep
“Achieving target lamb weights may offer the potential for lambs to be sold straight off the ewe and that is ideal if it suits the farming system, because it cuts out the post-weaning check in growth rate. Some producers are reluctant to sell in the late summer months because the price can dip, but research indicates that finishing lambs as rapidly as possible is usually the most profitable option.”
The size of ewe will affect the efficiency calculation, he added.
“A smaller breed will produce a better score. Entering an average figure of 70kgs instead of 90kgs in the above example can lift the figure from 50 per cent to 64 pr cent. This may raise questions about whether the farm is keeping the right type of ewe and there has been a trend of moving to a more lightweight breed in recent years partially for this reason. However, a lot will depend on the individual farm situation – a system which suits one unit may not be right for another.”
The lamb rearing percentage is another relevant figure, he said.
“This is a reflection of how many lambs are lost from scanning to disposal; both sold and kept as replacements,” said Mr Bevan. “A typical UK figure is 20 per cent and that leaves plenty of room for improvement, because some of the best producers are achieving a result of less than ten per cent It may be advisable to set a target of ten to 15 per cent, which would be regarded as very good, while 16-20 per cent would be classified as reasonable but improvable.”
High ewe losses or a significant drop in lamb numbers compared with scanning results can have a negative effect on lamb rearing percentage, he said. A lack of performance in these areas could be a sign of an ‘iceberg’ disease, so it is worth conducting a review of flock health management and possibly instigating some blood testing with the vet.
“Lamb rearing percentage is not a performance indicator that receives a lot of attention. Nevertheless, it can highlight problems that may be going unnoticed. A low score might prompt a review of pre and post-tupping feeding regimes, which could be responsible for poor scanning rates.
"Like the ewe efficiency tool, it can also be a sign of an underlying disease problem. Even the best farms can experience an abortion storm, but if it becomes a regular occurrence it is a cause for serious concern.”
He recommends that producers try the Upland Farmer Toolkit, to work out the ewe efficiency score for their flocks.
“The exercise will stimulate discussion and this may pinpoint elements of the management of the flock that could be improved. It is particularly relevant as we move towards a gradual decline in farm support payments,” said Mr Bevan.
The Upland Farmer Toolkit was produced by the Food, Farming and Countryside Commission, with funding from the Lake District National Park through the DEFRA ‘Farming in Protected Landscapes’ programme. For more information, visit www.uplandfarmertoolkit.org.uk.
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