Sheep farmers are being urged to supplement ewes to avoid the risk of low quality forages leading to problems with energy deficiency.
Martin Smith from UFAC-UK says that the warm wet winter could lead to farmers believing ewes can meet their energy requirements from forage alone, but in many cases this is unlikely to happen in practice.
“In many parts of the country grass has not stopped growing, meaning there looks to be plenty of feed in front of the ewes,” he comments. “However, dry matter and feed values will be low, potentially leading to ewes failing to get enough energy, especially as energy demands increase in late pregnancy at the same time that intakes decline.
“In the final month of pregnancy the lamb puts on 60% of its total weight, increasing the ewe’s demand for energy, protein and minerals but the growing lamb restricts the space for the rumen so nutrient density in the diet has to increase. In simple terms, forage will not supply what the ewe requires. Even with grass of good quality ewes will not be able to eat enough.”
Mr Smith says a failure to increase energy supply can lead to lighter lambs and an increased risk of twin lamb disease as the ewe mobilises excessive amount of body reserves to try and meet the energy deficit. Lighter lamb birth weights can have an impact on how quickly lambs will stand and suckle and can result in reduced weaning weights.
However, he advises taking care when meeting the energy shortfall by increasing the amount of cereal based concentrates fed as this can predispose ewes to acidosis which can be a significant problem.
“To increase energy intakes without the risk of acidosis, farmers should feed a supplement based on fats and oils. Choose a product based on soft, highly digestible oils such as soya and sunflower and which are rumen-inert to maximise their digestibility and the net energy benefit to the ewe.
“Ideally the supplement should also contain omega-3 fatty acids which have been proven to reduce time to first suckling by up to 50%. As lambs are born with very limited nutrient reserves, reducing suckling time can have a big impact on survival and growth.
“Effective supplementation which complements forages while reducing the risk of acidosis can have a significant impact on birth weights and early lamb performance, both of which have a proven effect on flock profitability. Investing in the right supplement and not over-estimating the contribution from forage can underpin flock performance,” Mr Smith stresses.