BY: BEN ALLOTT
On a breeding farm, weaning is the culmination of all your efforts through the year. Watching healthy well-grown lambs leave your farm and watching the next generation of replacements start their productive lives is your reward for all the work put into the past year.
It is also critically important to appreciate that your decisions made leading into weaning and the decisions you are about to make on managing ewes through the summer have a huge bearing on how successful you will feel this time next year.
Ewe condition is the top priority. At this stage of the year it is easy to focus on the short term goal of maximising lamb weaning weights and under appreciate the impact this focus can have on ewe BCS and mating performance next autumn. Some key points to seriously consider and talk to your neighbours and advisors about:
- By day 70-80 of lactation, ewes on good feed are only producing 30-40% of the milk yield they were at peak lactation. Ewes losing condition on tight allocations, or poor-quality feed, are producing even less. Lambs are now getting the majority of their energy for growth from pasture. In many cases, lambs will grow just as well and probably better if weaned early on to high-quality legume, herb, or brassica-dominant feed.
- Summer is a hard season to put weight back on ewes and you only have 90 days until tupping. In most pasture-based systems you are doing well if you can feed ewes to gain 50g/day. Over the 90 days between weaning and tupping this equates to just 4.5kg liveweight (roughly half a BCS). If you are a summer dry East-Coast farm with regular summer dry challenges, or a wetter North Island property with facial eczema, and higher parasite challenges through summer, then in many seasons this degree of summer weight gain is a real challenge. You cannot afford to see ewes losing condition leading into weaning in an attempt to drive lamb performance. You will struggle to gain this lost weight back in time for the ram.
- Ewes losing weight is inefficient – each kg of ewe liveweight loss releases 17MJ of energy to go into milk. It then takes 65MJ of energy above maintenance to regain each kg back through the summer. It doesn’t make sense to rob condition from your primary productive unit when the conversion to product is inefficient.
If feed is abundant, and quality is good leading into weaning, the pressure to make timely decisions is reduced. But if ewes and lambs are competing for quality feed, if lambs on mum are hardening off, if ewes stop gaining weight and god-forbid start losing weight then you are sacrificing next year’s potential by leaving lambs on mum. Make an early decision.
Prioritise summer feed into ewes who will lift production – there is no increase in mating performance gained by increasing ewe condition above a BCS of 3. There is a large lift in mating performance in lifting ewe BCS from 2 or 2.5. Immediately after weaning (do not wait a month), get ewes through and draft into lines based on BCS.
Ewes already at mating condition should go on to a maintenance only summer rotation. It makes no sense feeding these ewes to gain weight when summer feed is so valuable. Ewes below mating weight should be preferentially fed to gain condition to reach BCS of 3 by mating. This draft should be quick and easy. It is the best spend of time you will ever make to lift ewe flock productivity. If you require BCS training contact your Beef + Lamb NZ extension officer for details of the next BCS workshop in your area. And download the BCS pack from the Beef and Lamb Knowledge Hub.
CULL EWES WITH UDDER ISSUES
Uddering ewes – do not carry bad udders through the summer. Kate Griffiths has written and presented across the country detailing how significant the ongoing production losses are when ewes with udder defects are allowed to stay in the flock.
Ewes with a normal udder at tupping will lose 12% of her lambs on average through next lambing. Ewes with a lump or a hard udder at tupping will lose 30- 40% of their lambs the next season! My recommended approach: Udder ewes alongside BCS immediately after weaning and cull problematic ewes immediately (this picks up 50% of affected ewes). Re-examine one month later to pick up the other 50% that you missed at weaning. Talk to your animal health advisor about what defects you should be feeling for. Getting a conveyor in for this job allows you to BCS, examine udders, mouth ewes, and check feet all in one go.
Early weaning systems have been proposed as a way to reduce the conflict between ewe condition and the performance of the current lamb crop. Establishing high quality, high yielding legume and herb stands to wean young lambs as light as 16kg can introduce a huge amount of flexibility in tight years while also driving improved performance if implemented well.
Paul Kenyon has an excellent podcast on the Beef + Lamb Knowledge Hub – “Successful early weaning of lambs.” Take the time to investigate whether this management tool could be beneficial to your system and to identify the pitfalls to avoid.
Enjoy your success – take the time to reflect on a job well done. Have a beer. Enjoy your kids. Celebrate Christmas.
- Ben Allott is a North Canterbury veterinarian.
