Scanning is an important part of the measurements some studs take for their BREEDPLAN genetic evaluation. Choosing the time to scan seedstock animals often involves compromises between:
Season permitting, it is recommended that stock be scanned when they are in the best condition possible. This is particularly critical for marbling scanning (i.e. for ‘Intramuscular fat’, IMF). For optimal results with IMF scans, a minimum average rump fat depth of 4–5 mm is needed (this generally equates to 3–4 mm on the rib). If stock are way below this condition, it is generally best to delay IMF scanning until they improve. If the situation is intermediate, and you are unsure of IMF scanning but intend to scan for ‘Eye muscle area’ (EMA) and ‘Fat depth’ (FD), it is wise to ask the scanner to scan a few test animals for IMF and then to decide if it is worth continuing, or just to scan for EMA and FD.
While stock condition is critical for IMF scanning, it is not so critical for EMA and FD scans; however, it is still important for stock to have enough condition to allow genetic differences to show up. If all stock are, say, 0–2 mm fat depth, it may be wise to delay all scanning.
Balanced against the condition of stock, there will be factors affecting scanning time, such as:
Interim Carcase GROUP EBVs are generally available on cattle that are scanned when in a suitable condition, but after the main breed society GROUP analysis has been run. These Interim EBVs will rank the animals in a similar way to how they would have been ranked by the GROUP analysis.
Potential limitations of Interim EBVs include the following:
As the trend is for breeds to have a number of GROUP runs per year, as a general rule you should consider scanning when the animals are in the right condition.
For sale catalogues, Interim EBVs of young bulls are generally adequate and the sire results will be updated two or three times per year.
The acceptable scanning age range is 300–800 days, but 400–600 days is generally preferred.
BREEDPLAN and the breed societies will accept data only from accredited scanning technicians. You can obtain a list of accredited scanners from BREEDPLAN
While scanning conditions vary, the following steps should generally be followed:
Submitting the data to BREEDPLAN is the breeder’s responsibility. Ensure data is sent:
Preprinted recording forms are available from BREEDPLAN, or the data can be submitted electronically from your PC using various herd recording packages. Note that the information compiled by the scanning contractor may not be in a suitable format for submitting directly to BREEDPLAN. It is the breeder’s responsibility to ensure that the information is complete, correct and in the right format.
Brian Sundstrom is Cattle Breeding Coordinator with NSW Agriculture. Part of this role involves technical specialist and advisory work with BREEDPLAN from an office at the Agricultural Business Research Institute (ABRI) at Armidale. His other role is with the Beef CRC group.