Sheep farmers should mind the energy gap - say SAC vets

The snow that fell over the region caused huge problems for many farmers, struggling in desperate conditions to feed their stock.  Inevitably the big freeze disrupted feeding for many animals, putting pregnant ewes under stress.  This is because even in normal years ewes carrying twins and triplets often struggle to meet the energy demands of developing lambs – and this hasn’t been a normal year!

When any break in feeding occurs, pregnant ewes are forced to fill the energy gap by using their own fat reserves.  This places the ewe at risk of developing twin lamb disease.  Once twin lambs disease is established, attempts at treatment are often unsuccessful.  Less than a third of ewes affected by the condition make a recovery, and even fewer going on to successfully rear lambs.  For this reason, spotting problems early is essential.

SAC Vet Graham Baird says: “The best way of identifying a developing energy gap is to run a simple blood test on a selection of ewes in the flock.  This test measures a chemical we call BOHB, which increases in the blood when ewes are underfed.” 

These blood samples are best taken around a month before lambing.  For flocks with scanning results, sample five ewes carrying twins and five with triplets.  It is important to select early-lambing sheep in average bodily condition.  It will give shepherds time to make any necessary changes to diet.  For sheep that have not been scanned shepherds should sample ten animals of average condition.

According to Graham Baird one or two cases of twin lambs disease each year may represent the “tip of an iceberg”.  “Many other ewes could be suffering from a subclinical disease energy gap, which has implications for their ability to rear lambs successfully.  It’s vital to monitor energy balance in lambing flocks to prevent twin lamb disease.”

Graham Baird recommends shepherds should discuss results with their vet who can tailor advice to their particular flock or situation and help them towards a more profitable lambing in 2010.