April 13, 2024

Weekly Genetic Review: Increasing Lean Beef Yield – What We Can Learn From Steers Led at the Sydney Show

The 2024 Sydney Royal Easter Show ended yesterday.

The earlier part of the show saw sires of more than a dozen breeds displayed and judged, with animals entered from most Australian states recognized with ribbons and accompanying acclaim.

Underlying this year’s judging is the feeling for many that there is still the judging that will take place at Beef 2024 in Rockhampton in a month’s time, and the opportunity to see who will potentially gain national and international recognition for their cattle.

Preparation for stallion judging at Sydney’s Royal Easter Show is steer and carcass classes.

While there is a lot of attention paid to the parade and judging, an important benefit of the competition is the access to carcass feedback data and potentially the opportunity to consider the event as a snapshot, providing some points for breeders and others in the industry to ponder. and potentially address in the future.

In theory, the NSW Steer RAS competition is a unique benchmark for seed breeders.

The Sydney competition insists that lead steer entries are purebred only. Unlike other major competitions where led steers are usually crossbred and often bred for the purpose of earning hoof and/or hook ribbons, the RAS competition provides bull breeders with a direct chance to evaluate the performance of their purebred steers in various weight categories and against current MSA criteria.

Although the dietary regimen these animals were exposed to determines many of the final outcomes, there are still some useful feedback items that can help shape genetic decisions.

Carcass yield calculation

One of them is the percentage of lean meat yield recorded for each animal. Lean meat yield is expressed as a percentage (LMY%) and describes the proportion of a carcass that is lean meat (muscle) as opposed to fat or bone. It is calculated during MSA grading using a predictive equation that includes standard hot carcass weight (HSCW), eye muscle area and rib fat depth. When expressing the lean meat yield as a percentage (LMY%), it is independent of the variation in carcass weight.

Most significantly, LMY% allows bull breeders or commercial producers, as well as processors, to make standardized comparisons without the variation that may occur if using another yield calculation – % salable meat yield – which may vary depending on specifications. cut and may include some fat. For producers trying to increase salable meat yield, increasing the proportion of lean muscle in a carcass (LMY%) also increases salable meat in a carcass (SMY%).

Meat Standards Australia’s two most recent annual food quality updates included national average lean meat yield percentage results. In the period 2019-2021, the national average of LMY% was 58.7%.

This decreased slightly in 2021-23 to 58.5%. Out of curiosity, steers in the light and medium categories registered at the 2024 Sydney Easter Show had an average of 59.58%.

While it is useful to know the averages, there is progress not only in knowing the averages, but in identifying animals that perform better than the average and using those genetics, while also seeking to avoid genetics that perform below or below the average. far below average. average.

In national data, the range of all MSA graded steers saw lean % yield vary from 51.6% to 62.9%. Among cattle of all breeds and origins, this variation is perhaps not unexpected. Again, looking at the much smaller 2024 Sydney Show data set, the range in LMY% was even wider, stretching from 51.36% to 66.11%.

If all other characteristics are equal, this means a difference of 44kg of additional lean meat, between two carcasses of 300kg each.

The potential value of this data to breeders, especially breeders whose cattle have lower LMY%, is the insight it offers into selection decisions made in breeding and the emphasis placed on breeding herd musculature and sire selection.

Selection of animals for muscle gain does not automatically result in subsequent generations of cattle becoming larger or maturing later. Long-term research work on selection for bodybuilding conducted by the NSW DPI has demonstrated that selection for bodybuilding has not resulted in breeding females becoming larger or maturing later. In fact, body size becomes slightly smaller as musculature increases.

Most importantly, selection for bodybuilding did not have a significant impact on traits such as fertility in the more muscular breeding herd. There were also additional advantages for breeders, as replacement bulls had similar financial costs to less muscular bulls, but the progeny of the more muscular bulls were sold for a slightly higher value, resulting in a slightly more favorable financial outcome when compared to the average. of the less muscular herd.

On a broader industrial basis, improving lean meat yield offers producers the opportunity to increase carcass value and (given some form of industry progress towards value-based marketing) have a favorable impact on overall company profitability. .

This is possible to achieve without necessarily increasing herd numbers or impacting current stocking rates. While excessive LMY% can have a negative impact on overall MSA Index levels, the range that exists from the lowest to highest recorded LMY% shows that there is still room for producers to select and improve before most begin to encounter negative impacts on their food. quality index.

Alastair Rayner is a director of RaynerAg, an agricultural consultancy service based in NSW. RaynerAg is affiliated with BJA Stock & Station Agents. He regularly lists and sells cattle to clients, as well as participating in bull sales to support client purchases. Alastair provides pre-sale selections and ratings to seed growers in NSW, Qld and Victoria. He can be contacted here or through his website www.raynerag.com.au

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