Maximising pre-weaning lamb growth rates

// Rearing and Weaning

Strong lamb prices are an added incentive for farmers to maximise their pre-weaning growth rates this season.

lambs with ewes

On one of Beef + Lamb New Zealand’s many growing lambs’ resources, farm systems scientist Tom Fraser explains how ewes need a massive amount of feed in early lactation to provide adequate milk for her lambs while maintaining or recovering body condition.

Between week six and nine, a ewe feeding twins requires 4.27 to 3.84 kg DM/day (respectively). Tom says this means they should be running onto pasture covers of 1300-1400kg DM/ha.

“If pastures covers are too low, she physically cannot take enough food in.”

North Canterbury farmers Tom and James Maxwell mob-up set-stocked ewes and lambs into small mobs (around 200 ewes) as soon as they have finished lambing and rotate them around six or seven paddocks, moving them every two to three days.

This means both lambs and ewes are getting the pick of the best possible feed.

“Don’t try and clean up paddocks at that time of year.”

The pair admit it is a lot of work, as many mobs will have been shifted over 25 times before weaning, but they believe it is well worth the effort.

The Maxwells make use of the subterranean (sub) clover endemic in their hill country pastures to drive pre-weaning growth rates. 

This means actively managing the sub clover to allow it to set seed in late-spring and early summer and not grazing it too hard.

They also found a pre-weaning drench made a big difference to lamb weaning weights.

Farm consultant Jansen Travis says farmers often fall down in that late lactation period by not having the high-quality feed lambs need.

“In the early phases, pre-tailing, quantity is the issue, but after tailing it’s about quality.”

He says high-legume systems, or where legumes have been introduced, hold their quality and this is reflected in lamb performance.

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