Finding the optimal time to wean prime lambs often leaves producers perplexed.
But according to sheep and beef consultant, Dr Bruce Allworth of Charles Sturt University, the solution is in determining why you want to wean?
He suggested producers look closely at their enterprise, recognise their target market, and consider the season.
"There are no specific reasons to wean lambs, but as managers, there are three main reasons we need to wean," Dr Allworth said.
"The obvious thing we need to do when weaning is look after our lambs to give the lambs better access to feed and possibly allow better worm control, but equally important is to get the weight back on the ewes."
At four to six-weeks-old the lamb is still sourcing all it's energy from milk, but reasonably quickly, as the lamb gets bigger and the milk supply drops off, a quick changeover occurs and most of the nutrition comes from the grass.
Dr Allworth said a key observation to determine when this is happening is the distance the lamb is from the ewe.
"As lambs begin to eat they tend to drift further and further away. They are out grazing with the other sheep and hence competing with the ewe to get the grass.
"So if the lambs need better feed and you have better feed available, the sheep are going to benefit by weaning those lambs."
The second reason, Dr Allworth said, may be the most important of all.
When the ewe looks like she needs looking after, it's time to act.
"It's important to get the ewe back into good condition for an increased reproduction rate next joining," Dr Allworth said.
"This is particularly If you are lambing mid to late winter.
"By the time you wean their lambs in late November, they aren't going to have a lot of time and good nutrition to put weight on before you join them again in February.
"Every kilogram that you can put on that ewe between when you wean her and when you put the rams out will result in two per cent extra lambs next year."
He said ewes that are four to five kilos lighter at joining than they would have been by weaning a couple of weeks earlier could result in a 10pc lower lambing percentage the following year.
Identifying your target market and working with the season should play a major role in the decision, Dr Allworth said.
"The mere act of weaning lambs is going to cause them a setback," he said.
"Obviously if you are going to market those lambs straight off their mums, it's nothing to do with nutrition, it's all to do with stress and grouping animals together," he said.
"So if you are going to market those lambs straight off their mothers, you might leave them on their mums to 13 or 14 weeks so you don't get that setback.
"But if you are going to market your lambs eight to 12 weeks post weaning, I would be encouraging you to not delay weaning.
"Fourteen weeks from the commencement of lambing for a prime lamb flock is a good starting point."
But he suggested commencing weaning earlier than this if it's a tough season and if it's a good season, timing can be a little more relaxed.
"Both the ewe and the lamb should be doing well as long as there is adequate worm control," Dr Allworth said.
"Keep in mind If you wean your lambs every year at 14 weeks after the first lamb is born, in some years that will be spot on, in other years that will be the wrong time."