We visited the Edenbridge and Oxted Agricultural Show in Kent today, to test out the MSU3 Ultrasound Machine‘s backfat grading abilities on a range of breeds. Prior to this, our testing had been on single farms, on a limited range of breeds. As sonographers and researchers, we are always field testing the equipment that we stock so that we can be sure it is fit for purpose, so that we continue to improve it, and to ensure that we have the real life experience to support our clients in its use.
How this backfat tool works
The MSU3 has an imaging mode (ideal for pregnancy scanning) and a backfat mode. The backfat mode has three sites from which you can take measurements: lumbosacral junction, tenth rib and posterior shoulder. For each site, the scanner gives 4 numbers, and then displays an average.
A generous amount of gel is required in order to obtain good contact between the transducer and the skin.
What we found
We found that the MSU3 worked fantastically well on traditional breeds, giving a reading quickly and accurately on all three sites. Results were also highly reproducible between different operators. On very lean commercial pigs, however, it was more difficult to obtain a reading.
The other challenge was artefactual readings caused by the animal moving. The scanner will still give a reading if the pig moves while it’s generating its 4 readings for that site. It’s very obvious if one measurement is erroneous, as it will be so different from the others, so can easily be disregarded by the operator – however, future improvements to this technology could be to spot and automatically flag outliers.
The MSU3 is a fantastic, easy-to-use tool for backfat scanning, but for commercial breed pigs, users should be prepared for a short practice period. Do not expect to be able to obtain readings from every site on your first try, or for them to be valid at first! Just like other ultrasound techniques, such as gestational age calculation when pregnancy scanning, initial results will be unreliable. Repetition of the skill over a number of animals will improve accuracy and reproducibility.
Finally, it is important to remember that a tool like this will always require human input when it comes to interpretation of results. If a measurement is far outside of the norm for your breed, repeat it. If one of the 4 measurements does not fit with the other 3, discount it, or repeat the entire measurement.
Future work could compare the readings obtained on the MSU3 with abattoir results.