I heard Dr Bonsma speak on 3 different occasions, and he was truly an amazing man. There seems to have been many more cattle people in his era who truly understood structure, fertility and soundness.... and how they relate to each other. I think if more of today's cattle producers would take the time to go back and read what this man had to say, we may see some changes in what is considered a good beast.
Dr Bonsma was a great believer in the concept that to achieve excellence, and animal needed to be in balance. In one of his lectures, he discussed how every bone in the body needed to be in complete balance with each other in order to have structural soundness and fertility along with longevity. For example I remember him saying that the length of an animals head should be exactly the same length as it was from hooks to pins, and a certain multiple of the head length should be exactly the body length from the point of the shoulder to the tail head. I have some notes and literature I got from his lectures and I will have to try to find it. It has been a while since I looked at it.
I heard that Dr Bonsma could walk through a herd of pregnant cows and he would predict whether she was carrying a bull calf or a heifer calf by the color of the hair on the cows spine, as well as the gloss of the hair as well as the direction of the swirl on her back near the point of her shoulder. I have only ever seen this once before, and it was an old Montana rancher that my dad sold bulls to. I was quite young so I did not ask him too many questions, but I remember him walking through our cows and telling my dad the sex of each calf every cow would have. Our herd was all horned cows in those days, and he would look at the cows horns and tell dad whether she had calved regularly, if she had missed a calf in per years of production, and how many calves she had had in her lifetime. He did this by looking at the color of the horns, the color and size of the dark and light bands on the horns. This rancher wanted bulls with untrained horns, as he said these bulls would fight once and never fight again. They would spend the breeding season breeding cows and not just fighting. He was dead against using polled bulls, and I remember my dad wanting to get a polled herd sire, and deciding he couldn't afford to when this rancher would buy 18-20 bulls each spring. In those days that was a big chunk of my families annual income so it was important to keep a customer like this happy. I don't know why the knowledge of some of these old timers has not been passed down from generation to generation.
I am sure there are lots of articles on the internet about Bonsma and some of his lessons. I would suggest anyone to read some of these. I know I changed how I looked at cattle after I listened to him, even though I never followed everything he said.