The rabid wolf's bodily structure and appearance is incorrect; he has large, pointy ears, a tall head, and is large-sized and dark-colored. All wolves (including loafer wolves) have small, round ears, wide heads, and real loafer wolves were medium-sized and light-colored. Some of his socially interacting visual features and expressive characteristics are also incorrect; his canine teeth are covered, his nose is lengthened, his forehead is stretched, his neck is extended, and in various screenshots, his hair is sleeked. When aggressive, wolves' canines are always bared, their noses are always shortened, their foreheads are always contracted, their necks are always arched and their hair is always bristled (the wolf was actually played by a male German Shepherd, who was made to look like a wolf, and both Spike (Old Yeller) and the dog playing the wolf were muzzled and trained to play-fight for the sequence.)
When Rose is acting up and refusing to allow Travis to milk her, Old Yeller is called into the pen. It is led to be believed that Old Yeller's presence made Rose behave herself. However, it is obvious that what actually happened was that Rose was replaced with a much calmer cow. The reason this is known is because the calm Rose is wearing a different harness.