Australian flock uses NZ genetics to lift rearing by 20%

Switching to a self-replacing composite breed, selected for early growth and outdoor lambing, has boosted productivity on an Australian mixed farm.

The Greenline breed replaced the Merino-Leicester crossbreed 10 years ago at the Slade family’s farm Glenridge Park, Mount Barker, Western Australia (WA).

The Slades produce over 10,000 lambs annually for the North American market and breeding stock in an outdoor lambing system.

The Greenline has improved maternal ability, lamb growth and weaning rates. This has been realised in a closed flock to minimise bought-in disease risk.  

See also: Composite sheep breeds prove profitable alternative to old favourites

Farm facts: Glenridge Park

  • 7,000ha (18,000 acres) farmed
  • 7,500 Greenline ewes producing over 10,000 lambs
  • Small cheviot stud flock producing tups to sire ewe lambs
  • 550 Sussex suckler cows
  • 2,800ha (7,000 acres) of arable, growing barley, oats, lupins and oilseed rape
  • Supplying the Western Australian Meat Marketing Co-operative and Fletcher International Exports
  • 550mm (21in) rainfall annually
  • Employs six business partners and five employees

The numbers

  • 4.5:1 Feed conversion rates of lambs in feedlots
  • 2 Number of hours it takes to feed 9,500 sheep 7t of grain
  • 4,000 How many ewes a sheep scanner can scan in one day
  • 90 Typical number of Greenline rams the Slades sell annually

British ideas

The Slade family farm is run by David and Lyn Slade, son Andrew, and their daughter and son-in-law, Vanessa and Scott Hillman.

David’s father, Phil Slade, a renowned mixed farmer, first came to Australia from Milton Keynes in 1967 and seized the chance to farm on a larger scale in Australia.

David and Lyn Slade © Glenridge Park

David and Lyn Slade © Glenridge Park

Phil brought the idea of cross breeding and the border collie sheepdog and was able to show Australians the merits of British farming techniques and breeding.

This included crossing the Border Leicesters to Merinos to create a cross-bred ewe, breeding for lamb production rather than wool, and building soil fertility on arable ground with livestock.  

David Slade, who spoke to the Sheep Veterinary Society Conference this year, started farming sheep and growing crops on 890ha (2,200 acres) with Lyn in 1993. They now farm about 7,000ha (18,000 acres) and rent out 5,000ha to other farmers. 

The relative affordability of land (£4,693/ha) in WA and the ability to turn a profit in an unsubsidised industry meant the farm was able to grow as other farms sold up.

New Zealand ideas

However, about 20 years ago the Slades noticed that flock performance was faltering.

“Our system was to buy in Merino cross Border Leicester ewes annually, but we were also buying in ovine Johne’s disease, lice and worm resistance and foot-rot kept showing up,” says Mr Slade.

About 15 years ago, with ewe rearing rates at 110-115%, they travelled to New Zealand to visit several farms breeding composite sheep. They were most impressed with the philosophy of Kerry Dunlop at The Gree Farm near Winton on the South Island (see box).

Greenline breed

Mr Dunlop had been instrumental in developing the Coopworth (Romney cross Border Leicester) and bred the Greenline by crossing Coopworths with East Friesians and Texels.

“We were impressed by the commercial focus and outdoor, low-input system the sheep were farmed and selected on,” says Mr Slade.

They bought semen for £16.50/straw, imported it and artificially inseminated about 400 ewe lambs to Greenline semen in 2005.

The subsequent year about 600 shearlings and their Greenline cross ewe lambs were bred to Greenline semen.

“After about eight years we were fully switched over to Greenline and Greenline crosses, and have not bought a single sheep ever since.”


Rearing rates lifted to 137%, meaning the farm sells 1,650 more lambs a year. At a 22kg carcass at £3.56/kg, this has boosted turnover by about £129,285.

The commercial flock generally sees lamb losses of 10-20% from scanning. An elite Greenline stud flock has reared 150-165% in recent years.

Furthermore, the Greenline ewe mature weight is 65kg, making it 15kg lighter than the Merino cross Leicesters the farm used to use, which has enabled the farm to lift stocking rates 10%.

The farm could scan 10-20% higher but breeds early in February, to ensure grass is available for lactating ewes. The Mediterranean climate means lambs are weaned in November because grass burns off and disappears for five months of the year.

What the Slades learned from New Zealand

  • Self-replacing flock: The benefits are improved flock biosecurity and greater uniformity, meaning it is easier to identify the best sheep.
  • Select for early growth: The Slades breed for improved milk, early growth and maternal ability by selecting on eight- and 12-week weights
  • Balance structural soundness with index: Rams that are correct and mobile and in good condition from ewes that have lambed unassisted and required no treatments are then selected on index.
  • Be a commercial stud breeder: The commercial flock should be the bedrock of your income and the testing ground for your genetics. Don’t mollycoddle animals as they breed animals that need extra care themselves.

Australian tips for running productive and efficient sheep

1. Monitor and manage body condition all year round

Grass only grows from May (late autumn) to November/December (spring/late summer) and burns off by Christmas at Glenridge Park. Hay and homegrown cereals make up the ewes’ feed most of the year.

Expense is saved by weaning lambs on to hoppers and cereal stubbles when grass growth stops. Lambs are finished on a total-mixed ration based on clover and rye hay, lupins and cereal at 16% protein and 12% ME.

  • Body condition is constantly assessed, and sheep are well fed on hay and lupins (33% crude protein 15% digestible protein) around lambing to breed at a condition score of 3.5 and lamb at 2.75-3. Limestone is added to improve bone strength.
  • Thin ewes are sorted a month before tupping and fed cereals and hay to build condition before breeding.
  • Annual ewe feed cost for a twin-rearing ewe is about £16-£17 a ewe, with an output of £158.

2. Trace elements are key to support productive sheep

Trace elements are supplemented to ensure ewes are set up well to perform. The land is deficient in most trace elements.  

  • A multivitamin (zinc, copper, manganese, and selenium) and B12 injection are given to all sheep pre-tupping.
  • Selenium helps the ewes deliver the lamb and is supplied via a long-acting injection twice a year.
  • Zinc helps with infections, keeping mastitis rates down to 0.001%.
  • Selenium is applied to the land every year in a superphosphate fertiliser.

3. Investing in labour-saving devices saves money

Because labour cost is high (£25/hour), in normal years it only makes sense to run 3,000 ewes per labour unit. Machinery can be quickly paid off with economies of scale.

  • Large portable pens can gather and process 2,000 lambs at a time.
  • Crutching crates allow four people to crutch 2,000 sheep in a day.
  • A large army truck transports winter hay to ewes and can take eight tonnes at a time, feeding 30t every three days.
  • Grain is fed until grass growth gets going in July. Large trucks can feed 9,500 sheep in two hours, which drop 7t of grain every two days.
  • To maximise labour, teasers are used to bring ewes into heat and achieve lambing period of under 10 days, with about 1,000 lambs born each day.
  • Single-bearing ewes lamb in mobs of 200-500 head and twins in mobs of 200-300 head
  • The lambing round is done by one person each day, whose main job is to travel more than 80km/day, checking for cast ewes and difficult lambings.