Maximising weaner survival
Weaner deaths in both Merino and cross-bred flocks are highly variable and can cause significant financial loss to both the producer and the industry. Maximising weaning weight not only has a strong impact on the chance of survival, but it also reaps reproduction benefits with heavier weaners reaching maturity earlier and having higher lambing percentages as maiden ewes.
The excellent growing conditions this spring will hopefully translate into weaning weights above industry targets (23kg for Merino lambs and 30kg for 1st cross lambs). However, achieving this target does not guarantee success! Research shows that weaner survival is a function of both weaning weight and post weaning growth rate. In fact, low growth rates after weaning can cancel out the survival advantage that comes with higher weaning weight. Therefore, it is critical that weaners continue to put on weight and move in a positive direction.
The following outlines the key steps to maximising weaner survival.
1) Train lambs to eat grain: Train lambs to eat grain while still on the ewe so that weaners become familiar with it and can adjust immediately when reintroduced to grain. Without this teaching process lambs can take up to three weeks to accept the supplement.
Key points when feeding:
- Feed out 4 - 6 feeds of grain over a 2 week period just before weaning. This is enough to train lambs for life.
- Feed a rate of 50 grams/ewe (equivalent to 5kg of grain per 100 ewes)
- The longer the trail the better. This ensures all stock have access to the grain, particularly shy feeders.
- Feed out the same grain(s) that you will be feeding after weaning. Include lupins if they are to be used at a later stage.
2) Parasite control and vaccination: Remain vigilant with your vaccination and parasite control program. This includes:
- '6-in-1' booster vaccination: this is critical at weaning to protect weaners from the 5 clostridial diseases such as pulpy kidney and black leg and to prevent cheesy gland. Losses from these diseases are more common than thought.
- Selenium supplement: selenium deficiencies are more prevalent in young stock that are growing well and in seasons when we have high clover content in the pasture. There have been multiple cases this year in the Southern Tablelands where lambs have died from selenium deficiency. Supplementation of weaners on selenium deficient properties will be extremely important this spring to help prevent selenium deficiency symptoms such as weaner scours and failure to grow. Short and long acting selenium supplements can be administered via a range of products. Long acting slow-release injectables such as Deposel or Selovin are a cost effective way of protecting sheep for up to 2 years.
- Worm control: young stock are much more susceptible to worms than older stock. Drench weaners before putting them onto a clean paddock. Follow up with a worm test every 6 to 8 weeks to monitor worm status and the need for future drenching.
- Blowfly control: instigate a first class blowfly control program. Don't compromise by delaying the program or by using second best products.
3) Weigh and allocate to high quality, low worm pastures: Providing adequate nutrition is paramount in achieving and sustaining positive growth rates in weaners. Weaners have a high requirement for both energy and protein and this requirement should not be underestimated.
- Weigh and allocate weaners onto your best pastures. Pasture quality (i.e. digestibility) is more important than quantity. Feed quality declines as pastures mature and go through the reproduction phase (i.e. flowering and setting seed), so select pastures that are less advanced. Aim to keep pastures between 5cm and 10cm in height to conserve moisture and prolong feed quality.
- Access to good quality water is critical! If water consumption is down, feed consumption is also depressed.
- An initial liveweight at weaning enables you to monitor liveweight gain in the future and identify if they are heading in the right direction.
- Try and avoid paddocks that contain harmful grass seeds (e.g. barley grass, speargrass, erodium) as these can cause significant stress on the animal and ill thrift.
4) Monitor pastures and performance: Post-weaning weight gain is critical in minimising deaths and achieving the industry survival rate target of 95%.
- Weigh a random sample of weaners every 4 – 6 weeks over the summer – autumn period to monitor growth rates and check to see if they are heading in the right direction. Aim for a minimum growth rate of 50g/hd/day (1.5kg/month) for the first 2 months after weaning.
- Supplements will be needed as the season progresses and pastures mature. Adjust nutrition to meet target weights. Protein supplements become particularly important once pastures dry off.
- Lupin grain is an excellent source of protein (and energy) and complements cereal grains such as wheat and barley very well. The recommended mix is 80% cereal grain and 20% lupins. A weaner trial in the Yass district in the early 2000s showed that feeding 20% lupins in the ration was much more cost effective in terms of weight gain then feeding cereal grain alone.