IMF% is the numerical figure ultrasound machines provide. The percentage is a prediction of the amount of intramuscular fat in the ribeye muscle of an animal. Even though this figure is an estimate, it is one of the most powerful tools to the cattleman in today’s industry in selecting cattle with higher quality beef. IMF% and marbling are very similar but the main difference is IMF% is an estimate from a machine and marbling is an estimate of the human eye (the grader).
With an ultrasound machine a trained technician will collect several images between the 12th and 13th ribs of an animal. The images can either be read instantly by computer to determine the IMF% or they can be sent to a 3rd party lab (ex. Cuplab) where these images are then analyzed and results are provided around a week later.
When scanning yearlings as we do, we have to take into account that a yearling calf, especially an intact male, would perform differently than a steer calf finished out for slaughter would. Many operations adjust the score for males to a steer equivalent value. Many also adjust for age to more accurately compare an individual to the rest of its contemporary group. We have not adjusted any data we have previously publicized, but feel free to ask us if you ever have any questions.
As a cattleman, it is very difficult comparing actual scan data from different operations. The best way to compare data is within a herd and more specifically within their contemporary group. In our breeding program we select the animals that performed the best within their calf crop to help us improve the quality within our herd. Other operations may have pampered some of their animals since birth, so if you were to buy semen from a show bull who scanned a 4.5% IMF and a BF of .5, you should not expect his offspring to score nearly as a high for IMF in a commercial operation. Animals that combine the optimal combination of quality to Yield Grade should be utilized if you were looking to improve the carcass qualities of your herd.
The average brahman IMF score is from a 3.0 - 4.0 and of the ones that have been scanned the average BF is from .3 - .5”. At Kallion Farms, our Spring 2015 calf crop, which averaged 12 months old at scanning, averaged a 4.75 actual IMF and had an actual average BF of .17”.
We started our carcass based breeding program over 20 years ago and will never stop pushing forward in our search of excellence.