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Ewe Condition At Joining Is Critical To Increasing Lambing Percentages

Improving Merino ewe condition at joining could have significant impacts on wool enterprise profitability through increases in lambing percentages.

By Department of Primary Industries - 6th April 2004 - Back to News

In the current climate where surplus sheep make a significant contribution to the enterprise profitability, the effects of improved reproduction rate are likely to be large.

Merino ewe liveweight and condition score at joining are directly related to the number of lambs conceived. This effect is independent of liveweight change leading up to joining, ie it is the actual condition score or liveweight of ewes at the time of joining that is important not whether they are losing or gaining weight at the time. In a flock of ewes, each 1kg increase in average liveweight at joining will increase the number of lambs conceived by at least 2 lambs per 100 ewes joined. The scale of the effect on profitability depends on the responsiveness of the bloodline to improved nutrition, the "normal" condition of the ewes and on prevailing commodity prices. Wool producers should aim to have ewes in condition score 3 or above at joining to avoid suffering penalties of low ovulation and twinning rates.

Good preparation is the key to minimising reproductive wastage. We need to be thinking about suitable liveweight and condition targets well before the day the rams are due to go out. In spring lambing flocks joining tends to coincide with a time where feed quantity and quality are low and ewes are therefore likely to be losing weight over the period leading up to joining. It is therefore critical to have knowledge of both what condition the ewes are in prior to joining and the rate of weight loss that is occurring at the time to have any chance of meeting joining targets.

Planning for joining ideally needs to start in the spring in the previous year. If we assess the ewes a month before joining and realise the ewes are not on target it will, in most cases, be uneconomic to lift ewe liveweight and condition score prior to joining as the benefits of increases in lambs born will be out weighed by the costs of supplementary feeding. Feeding to maintain ewes over the period leading up to joining will always be more economical then allowing ewes to lose condition and then attempting to increase their weight just prior to joining.

Emphasis should be placed on maximising the peak liveweight and condition score of ewes in the previous spring. Effective utilisation of the spring flush will be by far the most economical way of increasing lambing percentages. If we have a knowledge of the likely weight and condition score loss over the summer months leading up to joining, we can set suitable targets for ewe liveweight at the end of the previous spring. Ewes typically lose between 0.5 and 1 condition score over this period, however this will vary dramatically between properties and between years and some monitoring through weighing or condition scoring of ewes will be necessary to ensure targets are met.

Strategies that keep ewes putting on weight for longer in late spring should be considered and implemented if thought to be practical and economical. This may include extending the quality of feed available by utilising strategies such as mechanical topping. If the season cuts out early, the early weaning of lambs should be considered to enable the breeding ewe to gain weight before pasture digestibility is reduced.

Source: http://gippsland.com/

Published by: news@gippsland.com