Weaners

Good weaner management can reduce mortality, improve the productive potential of the mature sheep and improve the profitability of the enterprise.

Weaner management should aim to ensure:

• Maximum survival rates by achieving satisfactory body weights at weaning and growth rates after weaning, especially in Merinos.
• Ewe weaners reach growth targets to maximise conception rates as maiden ewes or ewe lambs.
• Weaners destined for the lamb market reach growth targets to ensure delivery to market specifications.

Weaner survival and bodyweight correlation

There is a significant correlation between weaner survival and bodyweight at weaning. Producers should be aware of this relationship and manage weaners to achieve satisfactory bodyweight at weaning. Points to remember include:

• Small increases in weaning weight have a huge impact on weaner survival eg a 14kg weaner has a 34% lower mortality risk than a 12kg weaner.
• Small increases in monthly growth rates can dramatically reduce mortality rates eg an increase of 0.25-0.5kg per month can reduce the mortality risk by 74%.
• Faster growing and heavier weaners accumulate more body reserves that they can use if required.
• Supplementary feeding weaners may be a cost- effective option to decrease mortality rate.

Weaning paddock preparation

Weaning paddocks must be identified and prepared early.

Ideal features of weaning paddocks include:

• High quality feed - Ideally short green feed (1,200-1,500kg green DM/ha), preferably with improved pasture species and 20% legume. In the cereal zone, a specific fodder crop or good quality stubble is an option.
• Minimal grass seed - If there are no other options either spray, top or slash grass seed heads, particularly barley grass or corkscrew, to reduce the hazard.
• Low worm risk - Prepare paddocks to minimise worm egg burdens.
• Good quality water - Weaners must have easy access to good clean drinking water with multiple watering points in larger paddocks.

Weaning age

Merino lambs should be weaned 14 weeks after the start of lambing. Prime lambs can be weaned at 14 weeks after the start of lambing if good quality feed is available and they are being prepared for heavier markets.

At three months of age milk only provides 10% of a lamb's total food requirements. Weaning onto good pasture with a low worm risk at this stage will ensure continued growth and low post weaning mortality.

Ewes will also benefit once lambs have been weaned through regaining condition in late spring before pasture quality deteriorates with summer senescence.

Weaning procedures

Producers should aim to have weaners at 50% of their mature body weight as soon as possible post weaning. This can be achieved through weighing and drafting weaners into mobs for preferential management according to body condition and nutrition.

The highest mortality rates occur in lightweight weaners during the three months post-weaning. Management to increase weight gain will eliminate up to 30% of deaths. If pasture quality and availability is poor, producers should consider using available tools to formulate supplementary feed rations.

Monitoring weaner liveweight

For winter/spring lambs, producers should monitor weaner liveweight every 4-6 weeks throughout summer into autumn until pasture quality and quantity enable target growth rates to be met. Where possible, producers should re-draft weaners into appropriate weight groups and provide the best pasture to the weakest flock.

It is particularly important that ewe lambs meet minimum liveweight targets from birth to pre-mating.