Weaning within 14 weeks leads to ‘high growth rate’

Sheep grazing in stubble.
Camera IconSheep grazing in stubble. Credit: Kathy Saunders

Sheep producers have been urged to wean lambs within 14 weeks of them starting to drop to make the most of what nutrition is available in WA’s sparse pastures.

A dry winter has seen pastures die or be stripped bare by sheep picking at what is left across WA, leaving producers facing high feed costs.

Department of Primary Industries and Regional Development veterinary officer Danny Roberts said producers should be weaning at 12-14 weeks after the start of lambing.

He said this would help lambs “capture the highest growth rate and live weight gains” before pastures started to flower and haying off occurred.

But Dr Roberts warned lambs needed sufficient time to recover from marking, and the small lambs needed to weigh at least 10kg at weaning or “risk reduced growth rates”.

“Ewes will also benefit from weaning, as they have more time to regain condition to score three before mating to achieve good reproductive rates,” he said.

“Weaning also creates more flock management options, as ewes can be fed maintenance rations, placed on paddocks with less food on offer, or sold or agisted.”

Dr Roberts said weaning at 12-14 weeks provided greater flock management flexibility, while cutting down the cost of supplementary feeding.

Another benefit was the reduced risk of worms in lambs, which could cause scouring, flystrike and decreased growth rates.

“Lambs have no immunity to worms so it is useful to remove lambs from paddocks that may have been contaminated with worms by their mothers,” Dr Roberts said.

“Lambs should be placed on to paddocks with a lower worm burden after they have been drenched with an effective product.

“Research has shown weaners can be more resilient to winter worms when placed on to clean paddocks, achieving growth rates of more than 240g per head per day.”

Dr Roberts said weaners should be given selenium and cobalt before the spring flush and put onto clover-dominated pastures with a good-quality water supply.

Weaned lambs need to graze on food on offer, or FOO, levels of more than 1500kg per hectare to maximise their energy intake.

Dr Roberts said if this could not be achieved, a confinement pen or supplementary feeding in a paddock could be required.

“If lambs are unfamiliar with supplementary feeding, they should be trained to eat lupins, cereal grain or pellets while still with their mothers to avoid reduced growth rates two to three weeks after weaning,” he said.

“On weaning day it is advised that lambs ... receive a second vaccination for clostridial diseases and cheesy gland.”

Dr Roberts also advised farmers to optimise weaner production by aiming for a minimum live weight of 20kg and a condition score of two before the start of summer.

To find out more, visit the DPIRD season 2020 section on the website.

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