Profitability and performance in sheep farming these days comes from three factors "“ kilos of lamb weaned per hectare, kilos of lamb weaned per ewe, and the BCS (body condition score) of ewes at weaning. Talking at last week's Te Kuiti sheep seminar, organised by the Mid Northern Sheep & Beef Council, Feilding vet Trevor Cook highlighted the factors which arose for farmers in the 100 days after lambing starts reports Rural News. He sees the big three issues in terms of two major ones, conception rate and lamb growth rate, with a slightly lesser issue of lamb survival. If ewes are not at BCS 2.5 at lambing, the follow-on effects are lambs will be smaller at birth, the ewe will produce less quantity and less rich milk, and those lambs will never catch up in weight gain. Pre-lamb feeding of ewes is all important due to the sharp increase they experience in energy demands in the four to six weeks before lambing. Those carrying twins require 23% more feed, and with triplets an extra 44% is needed. The aim is for ewes not to more than 0.5 BCS at lambing, although it is more often 1.0 BCS. Cook agrees this is difficult to achieve on pasture covers alone, and farmers should be looking carefully at pasture growth rates in relation to quality. While in periods of extreme short feed supply, sheep farmers are now resorting to applying nitrogen, the quality of any additional growth from this must also be monitored. Cook urges farmers to keep the time off grass for their twinning ewes very short (eg from yarding) and to be careful about any feed changes close to lambing, as this could affect the lambs and in some cases result in lamb deaths (eg from changes in the milk).Carriers of triplets need special treatment, with an even feed intake, and a minimum time off grass. But they should not be overfed in last minute efforts to increase BCS. A daily growth rate for lambs being bandied about is between 300 and 400g/day. In reality though, for a 4.5kg lamb, most actually grew at 250g/day. This means "“ depending on issue such as weather and feed availability "“ farmers should allow for variation in time between docking and weaning so lambs are weaned at their heaviest weights.
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