Snow and ice covered pastures threatening 2011 lamb crop

Poor early winter grazing conditions nationwide are putting the 2011 lamb crop at serious risk unless farmers supplement ewe rations.

Thats the warning from Rumenco technical manager David Thornton, who says snow and ice covered pastures can compromise embryo survival.

All but the latest lambing ewes are now at the critical implantation stage of pregnancy. This process will not be completed for 3-4 weeks and any nutritional stress over this period can cause embryos to be reabsorbed, which means a lower lambing percentage. But ewes in good body condition score (>3) are less prone to losing lambs than those in poor condition (<2.5), he says.

He says that when grazing is covered by snow or has been subjected to repeat frosts, ewes outside in these difficult conditions must be given a maintenance ration.

Where silage is available without compromising stocks for later use in the season offer 1kg of dry matter to supply 9-10MJ of extra energy. Alternatively, provide 2kg of fresh straw, allowing ewes to select and waste. Allowing selection through the straw provides same nutrition as feeding medium quality hay, he advises.

In addition, David Thornton recommends giving ewes access to Rumevite High Energy + Protein feed blocks at the rate of 5-6 blocks per 100 ewes per week.

Alternatively, feed a small amount of cereal, but trough feeding at such a critical early stage of pregnancy may be counter-productive; excessive bumping and barging as animals compete for food can in itself also cause embryo losses. If cereals are fed, mix in a sheep mineral or provide a free-access mineral bucket.