Gross margin sensitivity analyses based on costs and feedlot performances of 149 steers of different genetic groups were performed. The genetic groups consisted of yearling Nellore, weaned Nellore, ½ Valdostana ½ Nellore, ½ Simmental ½ Nellore, ½ Braford ½ Brangus,½ Braford ¼ Angus ¼ Nellore, Brangus, ½ Canchim ¼ Angus ¼ Nellore and ½ Canchim ¼ Simmental ¼ Nellore. The gross margin sensitivity analyses were performed considering fluctuation of beef selling price, and buying price fluctuations of corn, soybean, corn silage and steers, maintaining all the remained costs fixed. For beef selling price of .99 US$/kg yearling Nellore was more efficient for fluctuation prices of corn and soybean, corn silage and the genetic group Brangus was more efficient for fluctuation of beef buying prices. For beef selling price of 1.27 US$/kg, the gross margin was positive for all genetic group, except the weaned Nellore for corn, soybean and corn silage buying price fluctuations; Brangus group showed positive gross margin for all animal buying price fluctuations. The animal gross margin showed more sensitivity to the buying price fluctuations in comparison to the animal selling price fluctuations.
cattle; genetic group; feedlot; cost; sensitivity
