Weaning More Lambs

Timely weaning sets weaners up for strong growth and survival while giving ewes the opportunity to regain condition before the next joining. It can also significantly reduce feed demand during the summer-autumn feed gap, improving whole-flock productivity. Early intervention also helps preserve ewe condition and maintain weaner performance when paddock feed availability is tight from a poor season.  

Timing is Everything

By 14 weeks of age, lambs get more than 90% of their nutrition from pasture and less than 10% from milk. This is why the recommended weaning age is generally 12–14 weeks from the start of lambing, although lambs can be successfully weaned as early as 8 weeks when conditions require. 

Early weaning requires careful management, however. Lambs should weigh at least 10 kg and, if mulesed, require a minimum of four weeks to heal before weaning.

The benefits of early weaning, particularly in below average to poor seasons, are substantial. Ceasing lactation dramatically reduces ewe energy requirements and feed demand. A 60kg lactating ewe with a single lamb equates to approximately 2.9 DSE, which drops to around 1.7–2.2 DSE once separated. Early weaning can reduce total flock feed demand by 25–40%, depending on ewe condition and lambing status.

Below is a summary of some of the key benefits from earlier weaning:

• Preventing ewes from losing further condition from ceasing lactation
• Reduced feed costs and improved efficiency of feed use due to the ewes' reduced energy requirements following weaning
• Increase ewes' reproductive performance next year by allowing extra time for the ewes to regain condition before their next joining
• Allowing targeted nutrition for the weaners to optimise growth rates
• Reduced worm burdens of the lambs because they are drenched earlier and are removed from pastures being contaminated by their mothers  
• Increased wool production from the ewes and lambs

If feed availability is tight but you aren't ready to wean early, creep feeding is an excellent alternative. This involves providing high-energy, high-protein supplementary feed directly to lambs while they are still with their mothers, using creep feeders that allow lamb access to the feed while excluding the ewes.

The Value of Imprint Feeding

To ensure weaners hit the ground running, imprint feeding is a valuable management tool. This involves supplementary feeding ewes and lambs at least four times during the two weeks leading up to weaning. Through this process, ewes effectively teach their lambs to recognise and consume supplementary feed.

Always use the same feed and feeding system that you intend to use after weaning. For example, if you plan to feed lupins and oats through self-feeders, use that exact combination during imprint feeding.

Without prior exposure, weaners can take weeks to learn how to eat supplementary feed, increasing the risk of reduced growth rates during the transition period.

Hitting Weaner Targets

The target liveweight at weaning needs to be at least 45% of a lamb's Standard Reference Weight (the mature weight of a dry, shorn sheep in condition score 3). If you don’t know what the standard reference weight is for your flock, you can calculate it using the steps described here. Following weaning, aim for a minimum growth rate of 50 g/head/day (1.5 kg/month).

Small increases in weight and growth rates can have a major impact on survival. A 14 kg weaner has a 34% lower mortality risk than a 12 kg weaner, while increasing growth rates by just 0.25–0.5 kg/month can reduce mortality risk by up to 74%.

Weigh weaners at weaning and draft the lightest 10–20% into a separate mob for preferential feeding. Monitoring the weight of a representative sample of around 50 weaners every 4–6 weeks will help ensure growth targets are being achieved.

Paddock Preparation and Animal Health

Weaners have developing immune systems and are particularly vulnerable to disease and parasites. Allocate them to paddocks with high-quality feed, aiming for approximately 20% legume content, low worm-risk, multiple good-quality watering points and limited grass seed burden. Optimising weaner health also includes monitoring closely for flystrike and ensuring the flock is free from lice, as their developing immune systems make them highly vulnerable to pests.

Ensure lambs receive their primary vaccinations at marking and the required booster vaccinations at weaning. For winter/spring-born lambs in moderate to high rainfall areas, an effective drench at weaning is generally essential. However, if your lambs were born later in spring and already received a drench at marking, you should conduct a worm egg count (WEC) at weaning to determine if they actually require another treatment. For weaners in the medium to high rainfall regions of southwestern WA, plan to conduct a follow-up WEC 6 weeks after their weaning drench, unless this timing overlaps with your scheduled summer drench.

Weaning is also an ideal time to review worm management strategies. Conducting a worm egg count before drenching can help ensure treatments remain effective and support responsible drench use.

Managing the Ewes

Once lambs are weaned, assess ewe condition scores and draft off those in poorer condition. Prioritise these ewes for better-quality pasture or supplementary feeding to ensure they reach a target condition score of at least 3 before the next joining.

Weaning is also the prime opportunity to review your ewe worm management. In higher rainfall regions, conduct a WEC on ewes at weaning (or 6 to 8 weeks post-marking if weaning is delayed past 14 weeks). In lower rainfall regions, ewes only require a WEC at weaning if more than 10% of the mob is scouring; otherwise, you can wait to test them just before harvest.

Ewes that reach joining targets are more likely to conceive, scan higher and rear more lambs the following season.

If you currently join for longer than five weeks, consider shortening the joining period. A maximum five-week joining reduces the variation in lamb ages and weights at weaning, makes management easier and gives ewes additional time to recover before the next reproductive cycle.

Key Takeaways for WA Woolgrowers

By focusing on timing, nutrition, animal health and ewe recovery, WA woolgrowers can improve weaner survival, lift reproductive performance and build a more productive and resilient flock. For a more successful weaning this year, consider the following key takeaways:

• Wean lambs at 12–14 weeks, or as early as 8 weeks: Early weaning reduces ewe feed requirements, preserves ewe condition, and drops ewe energy needs. Use creep feeding if paddock feed is tight, but you want to keep lambs on their mothers longer
• Imprint feed before weaning: Feed ewes and lambs at least 4 times in the 2 weeks leading up to weaning. Use the exact feed type and feeding system you plan to use post-weaning
• Target 45% of Standard Reference Weight (SRW) at weaning: Aim for this weight target, and draft off the lightest 10–20% for preferential feeding. Monitor growth by weighing a subset of 50 weaners every 4 to 6 weeks
• Optimise weaner health and paddock allocation: Place weaners in low worm-risk, low grass-seed paddocks with multiple high-quality water points and high-quality pasture (20% legume content). Deliver booster vaccinations at weaning, monitor for flystrike, and ensure the mob is free of lice
• Tailor your weaning drench: Drench winter/spring lambs in moderate-to-high rainfall zones. For late-spring born lambs, use a WEC at weaning to determine drench needs. Run a follow-up WEC 6 weeks later in southwestern WA wet zones
• Prioritise ewe recovery and conduct health checks: Separate thin ewes for preferential feeding to reach condition score ≥3 before joining. Perform a WEC on ewes at weaning in higher rainfall zones, or in lower rainfall zones if >10% of the mob is scouring

For more information and to check out the resources used in this article, check out the following:

• Winning With Weaners 1-hr workshop video - AWI 
• The Yarn Podcast Episode 253 “Winning With Weaners” - AWI 
• Making More From Sheep, Module 10: Wean More Lambs - AWI

Georgia Pugh, AWI Extension WA