I think that temperment is a highly heritable trait. Over the years you can notice a real difference between the temperments from both sires and dams. I had herd bulls that sire very docile calves that are quieter and easier to break than those from other sires that were raised in the same pastures.
At the same time, I also think that part of any calf's temperment is developed from the enviroment in which they are raised. You can see this in herds where the owners yell and scream everytime they work the cattle. You can see this in animals that are raised in herds that have little contact with humans for extended periods of time. I have seen it in ET calves that have a goofy recip mom. A few years ago, I worked with a group of ET Fullblood Simmental and Shorthorn heifers that had been implanted into Brahman and Brahman cross recip moms, in the southern US. The cows were completely bonkers and the calves were even worse. There were some pretty good heifers in the group from some very good donors that were extremely docile themselves, but some of these calves were killers. They would actually hunt you in the pen and put you over fences. We tried our best to domesticate these heifers and I don't think the owners were ever able to show or sell any of them, and eventually all but one was sent to a sale barn, as they were completely ruined as far as temperment is concerned.
That is why, I use my own recips whenever possible and I am pretty picky as to what the temperment of the recips is that get selected for embryos.
I have shipped some pretty good cattle to town just because of their temperments. When it comes right down to it, I maintain that there are enough quiet cattle on this planet to go around, and therefore we really should not have to tolerate the really goofy ones.
I have also seen several cases where a set of quiet animals, can be turned into beasts of flight by a single bad apple in the pen. Two years ago, I left a late born steer calf in with about 50 heifers for the winter. This steer was a little crazy when I weaned him, but I thought he would cool down once in with the heifers who were a very quiet bunch. The opposite happened, in that within a few weeks, the heifers were circling the pen when I went in. At first, I wondered if a neighbours dog was coming at night and riling the pen up . I also wondered if the steer was the cause, but I did not think that one animal ( and a small one at that) could do this in such a short period of time. The heifers continued to act nervous each time I entered their pen, so I loaded the steer and sent him to market. Within a few days I noticed a calmer group of heifers and within two weeks you had to almost push some out of your way to walk through the pen.
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