A DISCIPLINED approach to breeding and extensive recording to identify high performing genetics has led to Wirruna’s highly fertile herd with exceptional marbling.
Wirruna Poll Herefords, based at Holbrook, New South Wales, is recognised as one of the most well-recorded herds in the country for Breedplan, and has demand from stud and commercial producers in Australia and overseas.
Wirruna was part of the original validation project that became the foundation of Breedplan genetic evaluation.
Stud principal Ian Locke began carcase scanning animals for eye muscle area and rib and rump fat in 1990 and in 1998, marbling (intramuscular fat percentage) was added to the list of Breedplan traits.
“During the 1990s we were engaged with meat scientists and geneticists via Breedplan and had involvement in the Beef Cooperative Research Centre (CRC) projects established in 1992 and the launching of Meat Standards Australia (MSA) grading system in 1998,” Mr Locke said.
“For the first time, good science (Beef CRCs) and consumer taste tests (MSA) were gathering solid data around carcase characteristics and linking those traits to consumer taste, and marbling was found to be key to a satisfactory eating experience of beef.”
Marbling has since been a key trait in Wirruna’s breeding objectives.
According to June 2024 Hereford Breedplan, Wirruna prefix animals now represent 71 per cent of the top 100 animals in the Hereford breed for the IMF estimated breeding value (EBV), including the highest seven animals.
In the top 100 Hereford sires used, 41pc of the highest marbling sires are Wirruna prefix animals.
“Breedplan informed us that we had good variation of marbling in our herd, and with good heritability, we knew we had the scope to select for it and drive the trait in our herd,” Mr Locke said.
“Since that time, the accuracy of the IMF EBV has grown and Wirruna’s selection emphasis on marbling has resulted in the herd having the highest level of genetic marbling in the Australian and New Zealand Hereford populations.
“This has been achieved in a balanced trait selection approach, not at the detriment to other important cattle performance traits.”
The process of measuring the whole herd – carcase scanning both females and male to identify variation in the herd – has been key to the stud’s success.
“Being able to identify and select higher marbling genetics, both maternal and paternal, and being consistent with the breeding objective, has resulted in our top position in the breed,” Mr Locke said.
“Having an involvement in the Herefords Australia BIN projects and subsequent progeny testing activities to add actual carcase performance data of steer progeny to the reference population, and selecting outside AI (artificial insemination) sires that show good marbling traits has continued to improve intramuscular fat in the herd.”
While marbling has been an important component of Wirruna’s breeding objective, that trait selection hasn’t occurred at the expense of other important economic traits, like fertility or muscling, Mr Locke said.
Wirruna is a 5 star completeness of performance herd for Breedplan, which reflects the stud’s efforts to record as many of the animals and traits available, improving both the accuracy of the data and the ability to choose superior genetics.
“Our focus on driving index values is part of our breeding objective and is core to being able to achieve a balanced selection of a range of traits and assist with overcoming negative correlations between traits.
“From a commercial client’s perspective, having a higher marbling herd may yield benefits at the kill floor and to the end consumer, but the benefits aren’t close to traits like higher herd fertility, appropriate growth and calving ease outcomes that have direct influence on herd performance on-farm.
“Long-term clients recognise that building higher carcase quality into the herd is a long game and can position a producer into feeder and premium beef markets with a preferred supplier status.”
Many of Wirruna’s commercial clients are targeting feeder markets and selling direct to processors, particularly grassfed branded beef programs.
“Herefords particularly perform well in these grassfed markets, achieving good weight for age, with lower ossification scores due to earlier turnoff and the holy grail for these markets is to achieve marbling off grass.”
There has been no compromise to fertility with the focus on carcase characteristics.
Cows are run under high stocking rate pressure, with fertility being a high priority.
To remain in the Wirruna breeding herd, females are expected to raise a live calf at two years of age and every year after, with a tight six-week joining period. Cows that fail are culled from the breeding herd.
“Wirruna genetics have grown a reputation for being easy-care and easy calving,with good carcase shape and quality, and they’re docile cattle,” Mr Locke said.
“Over the years, particularly given our engagement with animal geneticists and industry research projects, we have come to recognise the benefits of various carcase traits, like muscle and fat, to other herd performance metrics, and we now identify higher muscle cows with improved fertility and calving ease.”
The work done to increase marbling was evident in the 2022-drop cohort of the American Hereford Association (AHA) National Reference Sire Program.
The evaluation was carried out by Olsen Ranches in Nebraska, producing 300 steers from 18 leading industry sires and measuring traits including feed efficiency (dry matter intake and average daily gain), birth and growth traits and carcase traits of muscle, fat and marbling.
The progeny of the only Australian bull tested, Wirruna Matty M288, topped the carcase test and finished in the top five of the growth test.
Matty’s progeny were among the heaviest at every weigh period and they graded 57pc prime, and the entire group graded 100pc choice.
On the AHA US genetic evaluation system as at June 2024, Wirruna Matty ranks in the top 1pc of the breed for their index values, top 1pc for marbling and carcase weight and top 23pc for muscle.
“These results serve as a good validation of the Wirruna program and its carcase credentials, not only domestically, but on the international arena” Mr Locke said.