We have just completed our second season of lambing on lucerne, and as Derrick said “things just keep getting better and better”…
We realised after our our first experience last year that the length of time the ewes were set stocked for lambing was compromising the management of the lucerne, so this year we scanned our the early, mid and late lambing ewes. This meant that instead of set stocking for the entire 45 days (the length of time the ram was out), set stocking only occurred for about 24 days.
This year the early and mid scanned twinning ewes went from grazing Ryecorn crops onto the lucerne paddocks that were going to be the last ones grazed in the spring rotation – as last year when we finally got to these paddocks they were greater than 45cm in height – far from ideal! They did a brief grazing on these paddocks for a couple of days – taking the cover from approximately 12 cm down to about 6 cm. They were then set stocked onto their ‘lambing paddocks’ four days prior to lambing, on pasture heights of about 12-15cm.
The critical component of our set stocking onto the lucerne is that we wait for 15cm height, and at a stocking rate of 7-8su/ha, ensure the lucerne grows ahead of the animals, with no major negative effects to the sward.
The lucerne lambing blocks are a mixture of lucerne and native – so there is variability in the ewes’ diet, along with shelter for lambing. Meadow hay is also provided in the more abundant blocks – (those with a higher proportion of lucerne). Thus no ewes are exposed to a complete dietary change, along with plenty of fibre readily available.
Ewes are set stocked into mobs of 50-80. We believe smaller mob sizes help with lamb survival and minimises the risk of mis-mothering, especially in mobs of twins. So, keeping the stocking rate per hectare about right has enforced the importance of subdivision and the need for more fencing.
In our two seasons of lambing on lucerne we have experience no animal health issues – no bloat, no foot scald, no bearings, no blown udders…just lots more lambs with ewes that are milking profusely. We were warned to expect many of these issues, amongst others, but we have religiously stuck to ‘the rules’, along with plenty of salt and fibre on hand, and gently managing any dietary changes.
About 10 days after lambing was finished, when lambs were big enough to travel ok, mobs were quietly merged together, and the rotation started. The merged mobs ranged in size from 250 up to 500 ewes with lambs at foot.
These mobs grazed paddocks for about 7-10 days, and then moved. Post tailing mobs were merged again, with average mob size about 500-600 ewes with lambs at foot, and again – never exceeding the 7-10 day grazing period.
Derrick tells us these are still a bit big, but at the moment these mobs sizes suit our paddock sizes. To cut down mob size would require more subdivision, but we are instead spending that money on more pasture renewal and sowing of more lucerne. At the moment we think the benefit of growing more lucerne outweighs any negatives from the big mobs, but we know it’s not best practice.
By providing shelter, plenty of high quality feed, and smaller mob sizes at lambing, we feel we have done everything we possibly can to get the best lambing results. The highest risk of lamb loss we have is losing twin lambs – which also means this is our greatest opportunity for more lambs – so hence looking after these girls better has the makings for some great numbers! In fact, 940 more lambs over the past two seasons – with potential for more.
|Mixed age Ewes|
Our other main issue to keep in mind is the nutrition of the lambs, and maximising lamb growth rates. Our lambs are born on lucerne, and it is their main source of diet right up until weaning. Being a store property, we aim to have our lambs weaned at 100 days, at an average weight of 30kg. Assuming they are born at a weight of 4kg, we need them to put on an average of 260gm/day to reach our desired target (we averaged 240gm/day last season over everything). They will only do this if:
- Ewes are fed well during lactation, ensuring plenty of milk production (the cheapest and easiest way to put on lamb liveweight)
- Pasture quality is maintained – ME content kept as high as possible, so each mouthful ingested is as high quality as possible (so controlling lucerne height – not allowing it to get away on us – hence the early grazing management prior to lambing).