Willatook farmer Tom Casey is reaping the rewards of a science-based sheep breeding system underpinned by rigorous long-term performance recording of maternal composite sheep.
This is based on the concept that fertility 'rules the flock' and relies on identifying and multiplying high fecundity genetics.
The objectives are to drive higher conception, lambing and weaning rates - and then produce high numbers of fast-growing lambs that meet market requirements.
Mr Casey, who farms with wife Olive, has long recognised that ewes are the key to making productivity gains in his sheep system and he started using composite Cashmore sheep 20 years ago.
Coopworth sheep were developed in New Zealand in the 1960s as a cross between Border Leicesters and Romneys, with Australian breeders developing them further to suit current market conditions - until they became the new Maternal Composite type.
It was a requirement that all breeding stock was performance recorded for a wide range of objective measurements taken across an animal's life.
This enabled breeders and commercial producers to build-up a performance history and genetic picture of an animal's earning potential.
The Caseys were attracted to this approach for breeding lambs and soon found the Cashmore composites sheep stood-up very well to their high rainfall environment.
"We have an annual average rainfall of about 720 millimetres and can have very wet springs," Mr Casey said.
"Ewes need to be able to tolerate cold, wet and muddy conditions - and internal parasite pressures - and lambs need good early vigor from birth.
"Cashmore lambs are real fighters and quickly start to grow and put on weight."
The Caseys have a pure Cashmore flock of 1800 head running on 324 hectares.
They use only sires from Australia's leading stud, Cashmore Oaklea, over their flock ewes.
Joining occurs in March for a late-August lambing, so that progeny is ready for sale as suckers in January.
Typical lambing rates are 150-160 per cent and a high proportion of the ewe flock produces twins and triplets.
"Multiple births are money in the bank," Mr Casey said.
This year, for the first time, the Caseys are trialing the tactic of mating ewe lambs at an age of about seven months to help fast-track production from the sheep system. This meant they were one-year-olds at lambing.
But previous research has shown the potential survival of embryos of ewe lambs is about 70 per cent, compared to adult ewes at 85 per cent - highlighting that older ewes still need to be the priority, as they are the flock's most efficient producers.
Mr Casey recommended that when considering the strategy of mating ewe lambs, it was important to firstly make sure to meet the needs of adult ewes.
"Then I would think about joining ewe lambs if seasonal conditions are conducive to having surplus energy on the farm to feed them," he said.
"I would only do this in good seasons and with the knowledge that maiden mobs will need careful treatment in late pregnancy and lactation to get them back into a good condition for the next joining.
"If there is insufficient time for post-weaning recovery of weight and condition score, the risk is that many high-value breeding animals will be empty at pregnancy testing and potentially need to be sold as 22-month-olds at low mutton values.
"If you get it wrong, the breeding animals that you spent development money on will give you one lamb and then that's it - they're out of the system."
Aside from putting a strong sire selection emphasis on maternal fertility, birthing and weaning rates, the Casey's also choose rams on Australian Sheep Breeding Values (ASBVs) for key profit-driving traits of early lamb growth, intramuscular fat and eye muscle.
They aim for lambs to hit the market in January when the major sheep sales further north in Ballarat and Bendigo are winding-down and processors start to look south for younger and 'fresher' lambs.
"We tend to sell in the Hamilton saleyards, and Midfield Meat International is one of our most regular buyers," Mr Casey said.
"Their feedback to us is that our lambs are high-yielding with good meat eating trait qualities."
Mr Casey said pasture growing conditions were excellent in the summer of 2019-20 and lambs were able to grow to 45-55 kilograms liveweight (and about 24kg carcase weight) by the time they were sold in January this year.
This was a growth rate of about 250 grams per head per day, achieved completely on pasture feed during spring and early summer - without the need for any silage or other supplementary grain.
The Caseys are looking for a repeat productivity performance during the remainder of this year, particularly with lamb prices coming off the boil by $2-3/kg from initial budget estimations.
"We really need our lambs to hold-on and keep growing right through the spring and summer months - and the Cashmore stock have proved time and time again that they will do this," Mr Casey said.
He said another market diversification opportunity that had arisen in 2020 was selling scanned in lamb ewe lambs, with a line of 300 marketed in June fetching $290/head.
"We would need to pick the seasons to do this, but it could be a good alternative income stream in future," he said.
In the past two decades, the development of Cashmore Maternal composites has needed to adjust to adapt to Australia's seasonal challenges that sometimes meant a dry spring finish or drought.
An early finish to the growing season created risks of lean and poor muscled carcasses and reduced lamb growth rates, which hit producers in the hip pocket.
To address this problem, the Cashmore Oaklea stud has been putting breeding emphasis on fast growth rates, high numbers of lambs weaned - from a moderately framed, medium wool ewe - and important meat eating quality traits.
Mr Casey said his commercial enterprise was able to track along the same lines, thanks to these efforts by the stud.
"Genetic progress - based on performance recording - for the key sheep profit-driving traits helps us to boost on-farm production," he said.
"This comes from the ability to run sheep at higher year-round stocking rates, have more lambs born and use a greater percentage of our spring and summer pastures to grow meat," he said.
"This means more kilograms of lambs weaned per hectare and higher gross income."
Cashmore Oaklea performance records its ewe stud flock of more than 9000 head, with comprehensive measurements taken across an animal's life.
It has also invested in developing novel traits, such as yearling weaning weight, parasite resistance and adult weight, that are now standard ASBVs - several of which the stud is leading in.
