2015-05-20    facebooktwitterrss

Weigh Lambs at Eight Weeks to Check Ewe Performance

The ewe’s ability to produce good quality colostrum and plenty of milk will influence a lamb’s performance in early life.

A ewes peak milk yield occurs three to four weeks post-lambing, so meeting the energy and protein requirements of ewes at this point is crucial in influencing the total amount of milk produced. Ewes rearing twins will need to produce around 40 per cent more milk than a ewe rearing a single lamb.

Lamb Weights

*Assuming 4kg birth weight

Lambs are entirely dependent on their mother’s milk for the first few weeks of life. A lamb’s rumen will develop as solid feeds such as grass and creep are eaten, and are likely to be fully functioning by eight weeks.

Weighing lambs at eight weeks of age provides a good indication of how well ewes have been lactating. Delaying recording weights until weaning will mean that the direct effect the ewe’s maternal ability has on early lamb growth rates will be missed. Whilst weighing lambs, make a note of ewe weight and body condition to compare with other records, this can provide useful information on how much of their body reserves have been used. Flocks with compact lambing periods may wish to use the mid-point of lambing to calculate when the eight-week weight should be taken. Alternatively, it is possible to calculate an adjusted eight-week weight for lambs if their date of birth and the date when they were weighed are known.

Knowing the flock average and individual daily liveweight gain can be used to calculate the benefit of supplementary feeding ewes post-lambing or creep feeding lambs. However, the birthweight must be accounted for in the calculation.

Results from an on-going research project, funded by EBLEX, suggest that the performance of lambs up to eight weeks is a critical key performance indicator (KPI). Sheep farmers are urged to check the weight of some lambs from birth to see how well they are doing rather than wait until weaning. This means that targets can be set and performance monitored.

Tracking why lambs haven’t hit target can also prove useful. The lamb could be a triplet, small at birth or may have had a poor mother. Collecting and analysing this sort of data can provide sufficient information to be able to implement steps to reduce it happening next year. It also might be appropriate to have some intervention plans prepared before lambs are eight weeks of age to ensure smaller lambs are not the ones still left on the farm next year. For example, weaning lambs early onto good grazing, introducing creep feeding (if not already doing so) or selling into a light lamb market.

To help prevent under-performing lambs, producers should ensure ewes are at target body condition score (BCS) at key times of the year. This could mean that thin ewes are supplementary fed post-lambing, there is a flock health plan implemented and that triplets are given priority grazing or creep feed.


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