If you use one of those tapes on calves under 500# I agree. I have found that using the hoof circumference tapes on newborn calves isn't as accurate as I would like either. We use the tape as more of a guage of how our steers are gaining weight. In fact, our county fair calves are weighed in and tagged in December. The day of the weigh in, we tape the calves and then compare that reading to scale. That gives us an idea how the calves "measure up" using the tape to estimate weight. If I had my druthers we would own a scale but that is one expense I can't justify at this point.