img_2358.jpg

Genomics PDS Trials DNA Tech For Commercial Heifers

I first wrote about HeiferSELECT in early 2018 and have been keen on the idea since the product was first released in late 2017. The big question is obviously around getting a positive return on the investment. At first glance, that investment of $38.77 (ex GST)/head seems like quite a lot for a cost that we’ve never incurred previously.

I’m pleased to say that we’ve now got a project underway to explore the value of genomics in a commercial setting. It’s a MLA funder Producer Demonstration Site (PDS) that will run for the next 6 years (5 cohorts of heifers). Six commercial producers are participating and around 60 other producers from the Mudgegonga/Murmungee, Kiewa and Upper Murray BetterBeef Groups observing. In 2020 we sampled 670 heifers across the 6 herds.

Aim

  1. Improve the selection of replacement heifers
  2. Improve the selection of sires
  3. Make faster genetic gains
  4. Better achieve stated breeding objectives

What problem are we trying to solve?

Compared to other production animals, cattle have a comparatively long generational interval so genetic progress is slow. Using all the available tools is the only strategy we have for maximising that progress. Making breeding selection decisions in commercial herds is done with even fewer tools than seedstock herds. Seedstock herds utilise pedigree, performance recording and evaluation and genomics.

In the commercial setting, many traits are not visible. Even with diligent bull selection that’s consistent with a long-applied breeding objective, significant genetic variability will still occur in the progeny. That’s just the nature of genetics. While the mob average will reflect the sire genetics, we don’t know which individual animals don’t meet our objectives for invisible traits e.g. carcase or calving ease.

In commercial herds, genetic gain is mostly driven by only half the mating through sire selection. Genetic progress can be sped up by applying more informed selection pressure on replacement heifers.

Environmental factors have a big impact in any breeding operation and produce a lot of noise, making it harder for us to evaluate the true genetic potential of young animals. Factors such as difference in age, whether their dam was a mature cow or heifer, health and nutrition, all have an impact on how genetics are expressed in the animal.

Genomic tools solve all these problems by providing objective predictions for visible and invisible traits, that are not subject to environmental influence. Genotyping our commercial heifers allows us to prune the tail-end of our genetic bell curve (histogram), and thus move the centre of the curve (the average performance of our herd) in the right direction at a faster pace.

That’s the theory anyway! Stay tuned to see if the results pan out.

The problem with selecting heifers on scales

Commercial producers largely rely on liveweight as their selection criteria. This may be having undesirable consequences:

  1. It favours older heifers over younger heifers. Heifers born early in the calving season are at a distinct advantage over later born heifers. 3 weeks is worth 20 kgs.
  2. It favours heifers with a higher mature cow weight (MCW). MCW is intrinsically linked to growth traits like 400D no matter how much your sire battery bends the curve. If your pushing growth, your likely to be pushing cows size as well.
  3. It favours heifers with a high birth weight. Bigger calves our of bigger cows tend to hit the ground running and out perform smaller/less robust calves in their first 12 months.
  4. It favours heifers out of older cows. Older cows produce more milk per day – especially when paddock nutrition is waning.
  5. It ignores valuable but invisible traits such as carcase characteristics. Increasingly, favourable carcase traits are being rewarded in the market.

What are the other benefits of genomics for commercial producers?

Reduce Dystocia

Any herds experiencing a high rate of dystocia may be able to make inroads by identify and culling heifers with poor calving ease scores. A few extra live calves might be enough to pay for the whole genomics program.

Provide insight into bull performance

HeiferSELECT will tell us the sire of each heifer. This may be useful in multi-sire joining scenarios to reveal which bulls are ineffective or which are throwing too many calves with white.

A useful marketing tool

In the early days this probably won’t be a factor as we selling the worst of our heifers. However later in the project when most of the herd is genotyped, we may have greater numbers of surplus heifers as our selection criteria increases. Having genomic data for the surplus heifers may increase their marketability.

BVDV Testing

There’s an optional add-on test available to screen the heifers for persistently infected (PI) bovine viral diarrhoea virus (BVDV) aka pestivirus. At $9 (ex GST) and no extra sampling costs it’s a pretty compelling opportunity that a couple of us are taking up.

Project Supporters

The core producers are making a significant contribution in both cash and time. We have support in the form of technical expertise from Angus Australia and Zoetis. Allflex Australia have made a contribution towards the matching tag sets (Printed management tags, NLIS tags and printed Tissue Sampling Units (TSUs) we are all using. Meat and Livestock Australia (MLA) are funding the project facilitation, administration, reporting and (hopefully) field days.

Allflex matched tag sets with printed management tags, NLIS tag and Tissue Sampling Unit (TSU).

I’m certainly looking forward to see how it goes. Keep an eye out for updates to follow our progress.

Comments are closed.