Northwest Veterinary and Supply also offers carcass ultrasound for feedlots. The software programming used was developed by John Brethour at Kansas State University. It offers the ability to scan and sort a set of feedlot cattle for marketing at a time of optimal profit. The cattle are ultrasounded and weighed at the time of final implant (between 80-100 days before finish). Cost of gain, premiums and discounts are entered into the program. They are then sorted (usually by tagging) into two to five groups according to finish date. Cattle are sorted by predicted subcutaneous fat thickness to avoid yield grade fours and fives, then by inner muscular fat to optimize the amount of cattle which have the genetic potential to grade choice, CAB, or prime. For example the animal which would normally be a yield grade four when marketed with the rest of the group can now be marketed 21 days sooner and as a yield grade three, saving a 20 dollar per hundred discount on the grid. The cattle which would be sold as select or choice, but are still yield grade two can be fed another 20-40 days and improve inner muscular fat to marketed as choice, CAB, or prime. The current select-choice spread is around $20 so on an average carcass of 800lbs that's 160 dollars. There's been a number of feedlot's using this technology for 10-15 years now including Cargill, and profit has been between $10 - $25 per head on the studies done. With the Current choice select spread as well as high feed cost the potential is there for more.