Lamb processing logjam if too many lambs drafted

Sheep farmers trying to get 40 per cent of their lambs away at weaning time may not be the best thing for the industry.

Rural Solutions consultant Graham Butcher said the processing industry was unlikely to want 60 per cent of farmers producing 40 per cent weaning drafts because it would cause meat processing issues.

Butcher advised farmers about how to achieve 40 per cent weaning drafts at a Beef + Lamb New Zealand Winter Seminar in Gore.

‘‘It’s a very productionorientated directive and it’s not really where the long-term industry needs to go about chilled supply, year-round supply and the lambs coming in to match that.’’

When aiming to increase weaning drafts, farmers needed to think about how they were feeding both ewes and lambs.

Butcher said Woodlands Research Farm data showed farms in the area grew about 45 per cent of their annual dry matter between September and December, with about 50 per cent of the metabolisable energy also produced in that period.

‘‘This is your best chance to grow lambs on low cost feed.’’

From mid-summer on it was harder to grow lambs because carbohydrates in grass declined, producing lower energy, and cellulose and lignin increased, causing lower digestibility, he said.

Another factor in growing lambs is milk production. Ewe milk production peaked between two to three weeks after lambing, Butcher said.

Single bearing ewes peaked at about 2.3 litres per day, while twin bearing ewes peaked at about 3.5l/day, he said.

However, twin lambs got less milk per day. ’’By eight or 10 weeks, the ewe’s milk production has dropped pretty dramatically to probably about one litre.’’

Therefore, lambs needed good quality grass to make up for the loss in milk production.

The onset of lactation depended on the late pregnancy feeding of ewes, but total milk production was set by feeding during lactation, he said.

Farmers needed to come out at the end of winter with at least 1200 kilograms of grass cover a hectare and not drive down covers by spreading ewes and their lambs out too early, have well conditioned ewes at lambing, which began at the previous weaning, and a lambing date which was close to the onset of grass growth, he said.

While targeting 40 per cent weaning weights might not be right for all farms, all farmers should be targeting higher weaning weights, Butcher said.