Article by Alastair Rayner, RaynerAg
The Spring Bull sales are well underway in Northern NSW. There have been a lot of successful sales in 2020, and this reflects a few things. Firstly there is a strong sense of optimism in the cattle industry, largely due to seasonal changes and strong market values. There’s also the influence of the intense selection placed on bulls over the last few years.
2020 bull sales have been highly successful to date
Breeders have definitely had a much greater level of selection placed on their bulls. Anything not making the grade has not been kept on for this years catalogue of sires. So this year is the year many people are using as the chance to upgrade their bull battery.
One message I have been providing for many years to producers is the importance of doing some research and preparation ahead of the bull sales. Its vital to think about the performance of your herd, and to look closely at the traits you want to improve or adjust to meet your environment and your markets. Performance records are a really important tool that can make these decisions more focussed and help refine selection of bulls for a program.
However not all data is the same, and it’s important to remember the difference between raw data (often provided on sale day) and performance records (published EBVs).
Consider selection of bulls as a process that starts well before the sale
EBVs are generated through the collection of large amounts of data that include not only the bull you are interested in, but the performance records of progeny, siblings and pedigrees. Collected over many herds and in many environments, EBVs are essential in describing the potential a sire can offer your future calves.
In contrast, raw data is really just a series of measurements taken at a single point in time, on one animal. There are people who use raw data in their comparisons, but if you do this, it’s important to realise that this data is a reflection of the nutrition and the pedigrees of animals in that particular program. However there are other factors that are in play as well.
These include:
- The age of the bull
- The age of the dam
- Was the bull a single calf or a twin
- Was the bull produced as a result of ET
These are all non genetic influences on the animal over and above nutrition and genetics. It’s very difficult to know what these additional influences are or how to account for them in a selection decision. The combination of these factors can mean producers looking at raw data are really looking at differences that are a result of these multiple factors, rather than for the genetic differences in animals.
Selection on raw data is further complicated by the heritability of individual traits. Highly heritable traits such as coat colour can be an easy selection decision, as these traits can be easily passed on to progeny.
However, as a trait becomes less heritable it is harder to see these differences reflected on the basis of raw data alone. Producers attempting to manipulate traits to meet breeding objectives in areas such as female fertility have a harder job to select for improvement when they are reliant on raw data and visual observation. It’s not an impossible task, however it is a much more difficult, and drawn out process over several generations.
Selection includes analysis of EBVs, physical inspection and looking at raw data
There is also a third consideration. What is the relationship between the trait that has been recorded and the traits that are the focus of breeding decisions? Not all traits follow linear progressions. In the case of scanned data for EMA. The size of EMA at a particular point in time may not be reflective of increased muscularity, but rather a result of growth rate to that point in time. A larger EMA may be more reflective of the growth and weight of the animal when it was scanned.
I’m often concerned when producers place all their emphasis on the raw data of animals as the basis for their selection decisions. Without knowing the cumulative impact of the environment, feed, and other non-genetic factors, bulls are being selected more on reflection of the year’s circumstances, rather than on their genetic capability. This often works in a counterproductive manner to selection pressure placed on the breeding group at home.
Bidding on bulls should be the final step in a process that started at home thinking about the traits you need to meet your breeding objectives
Early planning allows time to consider a wider range of more accurate information and to consider the availability of data from Breedplan rather than reliance on raw data on sale day. Combined with selection pressure these two areas do have a positive influence on genetic progress in any herd.
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