Lambing percentages have nearly doubled in the eight years since changing bloodlines at Bellevue.

They have gone from 75 per cent to 140pc last year and the worst during the drought was 102pc. Last year their Merinos scanned 162pc resulting in 140pc lambs marked to ewes joined.

David Greig puts it down to the change in genetics through the introduction of Mumblebone blood.

With his wife, Melissa and his parents George and Margaret, the family runs Bellevue Rural Enterprises of mainly red soil to softer greyer loam country on 5300 hectares 20 kilometres north of Tottenham.

Preferring to concentrate efforts toward breeding ewes, the Greigs turn-off their wether lambs as soon as practicable after weaning.

They joined 2600 ewes in February last year and plan to join 3500 this year including 600 ewe lambs now running on a lodged oats crop and supplemented with lupins since December.

"Our plan is to put weight on these young ewes and join them at seven months-of-age on March 15 for five weeks," he said.

Teaser wethers will be put in among the ewe lambs for the first two weeks of the main joining starting on March 1.

"Then we'll keep a small team of rams for the ewe lambs to start their joining on March 15.

"Our main joining will finish three weeks later and we'll give the ewe lambs their final two weeks with the entire ram team to pick up any on their second cycle."

Mr Greig said it was important to keep the ewes growing up to their effective puberty weight.

"We found last year joining weights in our first-cross (Border Leicester/Merino) ewes were much lower than recommended," Mr Greig said.

"We joined these ewes at 35 kilograms when it was recommended at 45kg, and two-thirds got in lamb at an average 35kg.

"So we are thinking now with the genetics we are using that our Merinos are maturing at a much lighter body weight too, which means they are cycling a lot earlier at a lower body weight."

Mr Greig said he was trying to get as many ewes in his breeding system as possible so there would be more surplus ewes to sell after classing, which he does himself between Christmas and New Year. The oldest ewe on Bellevue is five-and-a-half years and those may be sold scanned-in-lamb. In 2018 as the drought started to bite all ewes four-years and older were sold.

Mr Greig had read recent research that feeding ewes a higher Omega-6 diet could skew the sex ratio of the lamb population.

"Our ewes are on a lodged oats crop which is high in Omega-6, so we are hoping for more ewe lambs, which works with our planned ewe flock increase," he said.

"Even if we can get a 10pc skewing on the population it's extra dollars in those ewe sales."

Shearing starts the first working week of January and Mr Greig said six-month shearing made it difficult to class a sheep younger than 18 months of age.

"I don't believe classing at 12 months can be as correct with the difference in wool length, so you've got to literally class them a week before shearing," he said.

"Any time before and the wool is too short to see differences in staple length."

Fleece weights are close to 2.4kg clean, nearly 5kg clean for the year and Mr Greig believed he hadn't lost any woolcut from changing his sheep from a predominantly wool focus to far more dual-purpose and more fertile and productive.

"Six-months shearing has given our ewes a better condition score and we have also significantly reduced our ewe mortality rate through the years," he said.

"Fly waves are of little concern now with up to six months in wool.

"It's still an issue, but not as bad as if they had longer wool which tends to hold moisture a bit longer."

Bellevue sheep haven't been mulesed for three years.

"And that's going well for us," Mr Greig said.

"We are gaining interest from people wanting to buy non-mulesed ewes."