Beef Progeny Test 2025: Genetic insights for NZ beef industry
At Pāmu’s Kepler Farm in Manapouri, mating has wrapped up at the across-breed Beef Progeny Test.
Now entering its sixth year, the progeny test is a cornerstone of the Informing New Zealand Beef (INZB) programme.
On Kepler farm, Hereford and Angus cows are run side-by-side with crosses undertaken both ways. This replicates the crossbreeding systems commonly used by commercial beef breeders across New Zealand.
Data is collected from conception through to processing, including carcase data from calves and reproductive data from heifers born into the programme. The test retains purebred and first-cross heifer progeny (where commercially viable), evaluating them under natural service for at least their first two matings. Last year’s mating at Kepler achieved a record 70% conception rate via artificial insemination.
Jason Archer, head of genetics at B+LNZ, says the Beef Progeny Test (BPT) plays a critical role in creating a stronger future for New Zealand beef farmers and the industry.
“It allows us to evaluate good bulls on the same level playing field while demonstrating the differences and similarities between the breeds, as well as the benefits of hybrid vigour - and the opportunities this presents for ongoing genetic improvement.”
Breeders of bulls selected for use in the BPT receive detailed information about the performance of their bull’s progeny, including processing data (in the case of steers).
Read More:
- Beef Progeny Test 2025: Genetic insights for NZ beef industry
- The genetics of body condition scoring
- Planning, Feeding, and Genetics: Key to Yearling Heifer Mating Success
The across-breed progeny test builds on data gathered from the original Beef Progeny Test (2014-2020), which compared bulls across several large-scale commercial beef operations nationwide.
B+LNZ continues to analyse the dataset collected over the course of the original Beef Progeny Test and the current across-breed Beef Progeny Test to provide valuable insights for stud breeders and commercial farmers.
A series of short articles by scientist and ‘data wrangler’ Dr Nicola Dennis brings to life some of these findings.
Topics covered include mature live weight and growth, the genetics of body condition scores, increasing beef marbling without excess external fat, carcase rib fat depth, and how ultrasound scanning can predict marbling in beef. The articles can be found on the B+LNZ website.
BCS for Bulls
Cow body condition score is one of the key factors to manage throughout the farming calendar.
A breeding cow with a bit of spare energy stacked on her back is more productive, more robust, and better-looking. But where does genetics come into all this? Could your bulls be working harder to produce full-bodied bovine goddesses of fertility?
Right now, there are no body condition score (BCS) breeding values calculated for most kiwi bulls. But outcomes from the B+LNZ Genetics Beef Progeny Test have shown that there could be.
Over 240 sires have been assessed for cow BCS in the B+LNZ Genetics Beef Progeny Test and more than 4500 cows have had their BCS measured at three time points: prior to mating, at weaning and prior to calving. There was quite a range of average cow BCS scores between sires (graph below). The heritability of cow
BCS was 0.26 indicating that around 26% of variation in cow chunkiness can be attributed to genetics. So, there is plenty of opportunity to add extra love-handles to your herd via bull selection.
The researchers also looked at related traits. There was a genetic correlation between cow BCS and the existing rib fat depth trait (measured via ultrasound in finishing animals). Bulls with a higher genetic merit for rib fat depth tended to have daughters with higher cow BCS. However, the genetic correlation (0.29) was not strong enough to consider rib fat depth a good predictor for cow BCS on its own. This means that rib fat depth EBVs only explains 8% of the variation in cow BCS. Likewise for the eye muscle area trait (4%).
And since rib fat depth and eye muscle area are measured in finishing animals which don’t have the demands of calving and lactating, there is a case to be made for adding a dedicated cow BCS breeding value to future genetic evaluations.
Dr Nicola Dennis
