Three groups of nine steers each were fed fattening diets, containing either non bird-resistant (NBR), paraformaldehyde-treated bird-resistant (PBR) or bird-resistant (BR) sorghum grain as the energy source, for 105 days. The BR group performed consistently worse than both the NBR and PBR groups. Although not statistically significant, there was a tendency for the NBR group to perform better than the PBR group.