Early lamb weaning studies under way at Massey

New research into lamb weaning.

New research from Massey University suggests that lambs can be successfully weaned lighter and earlier, with benefits for the mother as well.

The University’s Sheep Research Centre has shown lambs of ewes feeding on a legume-based diet can be successfully weaned at approximately 50 days old, or seven weeks, when they are as light as 16kg.

Under the correct conditions, the early weaning allows the lambs to grow faster and the ewes to regain more body condition before the next breeding season.

Traditionally, weaning occurs at 10 to 12 weeks after lambing, when the milk from the ewes reduces, and is a critical factor in the future performance of both the lamb and the ewe.

The study is funded by Beef & Lamb New Zealand, and is driven by the expertise of Massey’s Dr Rene Corner-Thomas, Dr Lydia Cranston, Professor Steve Morris and Professor Paul Kenyon.

Dr Corner-Thomas says that early weaning can have advantages for both the ewe and the lamb.

“There is a gradual decline in milk production after ewes reach peak milk production within three weeks of lambing. Weaning early allows the ewe more time to gain body condition before the new breeding season starts in the autumn. This is important for when summers are dry and late spring is the only chance a ewe has to gain good condition before the next breeding season.

“For the lamb, earlier weaning is an advantage when their growth rate is restricted by ryegrass and white clover pasture covers below 1000 kg of dry matter per hectare in late lactation. In these conditions, weaning early onto a legume-based diet will increase the growth rates of the lamb. The ewe will also maintain her body condition. The legume-based diet can either be a herb clover mix or a pure lucerne stand.

“If ryegrass pasture masses are above 1400 kg of dry matter per hectare however, there is likely little benefit from early weaning for the lamb, but it is still positive for the ewe.”

Previous studies have shown that when early weaned lambs are slaughtered at a traditional weaning age the dressing out percentage of early weaned lambs did not differ from those sent directly to slaughter off their dam.

Mr Jay-Ekanayake, Dr Lydia Cranstonand Dr Rene Corner-Thomas

Further research

The team will undertake further research this spring to determine the optimum management of early weaned lambs.

This study will involve PhD student Jay Ekanayake and have three main focuses. Firstly, to determine if lambs can be weaned as light at 14 kg onto a herb clover mix and still achieve suitable growth rates.

“Studies have also successfully utilised both herb and clover mixes and lucerne monocultures to grow these young lambs. A large number of lambs can be finished to slaughter weight on a relatively small area of these crops,” says Dr Corner-Thomas.

Secondly, they will look at the best management of the lamb prior to early weaning to ensure an easy transition for the lamb. And thirdly, determine if there are any negative impacts of early weaning on the health of the ewes’ udder.

Further studies are planned for 2018 to examine potentially lighter weaning weights and ages.