Two tools to turbocharge genetic gain

Weaners moving onto grower country cells on Andrew Mactaggart’s (case study below) property in Duaringa, Central Queensland.

Northern beef producers have two new tools to drive fertility in their herds.

MLA-funded Genomic Breeding Values (GBVs) and herd profiling are designed to boost fertility in high-value commercial production systems.

They allow producers to identify high performing replacement females, for greater transparency in management decisions to fast-track productivity gains.


Benchmarking is an important tool to identify opportunities to lift herd performance, but until recently, the ability to benchmark the genetic potential of commercial herds was limited.

An MLA project in partnership with the University of Queensland (UQ) has closed the gap between possible genetic gains and the gains producers are currently achieving in northern beef production systems.

The project, which has just finished, used a large reference population to map a range of traits related to fertility.

Clara Bradford, MLA’s Project manager – Livestock Genetics, said unlike previous models which focused on recording genetically diverse seedstock animals, the UQ project recorded phenotypes and genotypes of commercial herds.

The 54 collaborator herds involved in the project contributed 26,000 commercial females, which were recorded for age at puberty, return to oestrus (P4M) and other production traits, as well as new traits such as tick resistance.

“The aim was to provide a tool that could utilise the technology of genomics for commercial production systems, where they don’t have the level of recording or accuracy that a seedstock herd would,” Clara said.

Two products emerged from the project:

1. GBVs and herd profile

“A GBV is a trait based off a genomic prediction developed from a large commercial reference population,” Clara said.

“It allows producers to select commercial females that are better for fertility and growth, or teams of bulls from crossbred or composite breeds that are part of the reference.”

While the products allow producers to test bulls, they don’t replace estimated breeding values (EBVs).

The GBVs can help producers select their highest performing heifers in a more objective way.

“If you had to pick 20 heifers from 100, the GBVs allow you to select them on their genetic potential for key fertility traits, instead of on pedigree, the way they look, or how much they weigh,” Clara said.

“It’s less subjective, more objective.”

2. Herd profile

If a producer has never done any form of genomic testing or used breeding values before, the herd profile tool will benchmark where their herd sits.

“If you have a breed that has EBVs, you can do a herd profile that will tell you where your commercial females fit. You can then purchase bulls with EBVs complementary to those females,” Clara said.

Producers who are aiming to drive production can find bulls that sit in the top 1% of the breed and use those animals to put their herd on a fast trajectory of increasing genetic progress.

“If you have a terminal herd, you’ll make some very quick gains. In a self-replacing scenario, one bull will have an impact on your herd for 10 years.

“Being more informed in the way you make that decision will positively impact the productivity of your herd for generations.”

Seasonal action plan

  • If you have spring-born calves, now is the time to assess which of these could be replacement females.
  • Bring them into the yard, test them, draft according to which you are going to keep, and which will be sold or put through a feedlot program.
  • Do a herd profile to benchmark your herd in preparation for upcoming bull sales.

Meet the producers

Meet Andrew Mactaggart and Michael Flynn, two of the northern beef producers who participated in the MLA/University of Queensland project to develop new genetic tools.

Andrew Mactaggart

Andrew Mactaggart and his family run a multigenerational beef enterprise north-east of Duaringa, in central Queensland.

They have 2,500 open composite breeders, with 40–60% Bos indicus content and a balance of British and European genetics, capturing the benefits of hybrid vigour.

Andrew provided the UQ reference group herd with two cohorts of yearling heifers in 2017 and 2018.

“We didn’t have specific goals going into the project, but we could see that if the research team could identify a genetic marker for fertility in northern beef herds, it was going to be good for the industry,” Andrew said.

The heifers were scanned at approximately 300kg to determine the presence of a corpus luteum, indicating oestrus cycling, then scanned for pregnancy and foetal age after joining. They were then scanned 12 months later for a rebreed pregnancy.

The scans determined approximate age of puberty and ability to rebreed while lactating (known as P4M – pregnant four months after calving). While it took a few years before data collected delivered the indicators, the results have allowed Andrew to benchmark his herd.

“A single benchmark can be dangerous, but a series can show you the trend of where you’re headed,” Andrew said.

“The value is in knowing how far towards your goal you are, and if what you’re doing is moving you in the right direction.”

As all the bulls he uses are contract bred or home bred, Andrew also selects bulls using GBVs, in addition to existing systems.

“GBVs have given us more robust data to work with, particularly for hard to measure fertility traits,” he said.

“This is a significant tool for commercial production. It really lifts the ability to measure objectively, in a cost-effective manner, for producers who are not registered breeders or part of a breed society.”

Michael Flynn

Michael Flynn has a Droughtmaster bull breeding operation south of Augathella, Queensland.

Each year the Flynns join 3,000 females and produce 500 bulls.

Michael is also a cattle vet, focusing on fertility and profit for clients.

For almost 50 years, he’s been selecting for fertility traits using traditional breeding methods.

“It’s a really slow process,” Michael said.

“You can’t get enough data, and by the time we know a sire is throwing heifers that are performing for us, he’s long gone. These new tools allow us to select bulls as calves that have those traits ingrained.”

Michael provided the UQ reference group herd with two cohorts of maiden heifers, and said the genomic testing showed them that in terms of fertility, they still have some genetically inferior animals that are not being identified by traditional performance records.

“It’s disappointing on one hand, but it’s also exciting, because it shows us the potential for these tools to accelerate the program,” Michael said.

“For too long the beef cattle industry has been selecting their bulls on inadequate information, us included.

“We’re going to be able to make enormous genetic gains by picking bulls on their genetics, not on their looks or showring success.

“These tools will revolutionise the beef industry.”

/Public Release. View in full here.