Fickle spring lamb growth reveals varied impact of extended winter
Published 15/06/2010 | 05:00
IT'S 12 weeks since St Patrick's Day, the traditional lambing date for mid- season lowland flocks, and the first draft of single lambs should be nearly ready for the factory this week.
But there are mixed reports on how lambs are performing. Some farmers are pleased with the lamb growth rates being achieved, but on other farms where grass has been scarce the spring lamb growth rate has been poor.
The extended winter slowed grass growth in the early part of the year and the impact of that, in parts of the country where grass was in short supply, is now being seen in some flocks.
Twin lambs should gain 300g per day during their first 14 weeks of life, so the target for twin lambs born on March 17 should be an average of about 34kg live weight by June 23.
Growth rate is usually slightly higher during the first 10 weeks, while it will start to decline a little in the final four weeks before weaning. If the target of average 300g/day live weight gain is not being met, you need to assess what can be done to lift performance.
It's also important to keep lambs moving off the farm and to draft them as they become fit for slaughter. There is often the temptation to keep lambs longer to bring them into higher weights. But this approach can often backfire in the form of factory penalties for overweight or over-far lambs.
Lamb prices are currently running ahead of last year, but the trends from recent years are worth noting. Prices tend to drop significantly in June and July, and this was particularly noticeable last year.
Based on that trend, it might be wise to take advantage of the current price. A 39kg lamb, killing out at 18kg carcass, may be worth more in June than it will at 47kg and killing out at 21/22kg four weeks later.