Many years ago, an old rancher from Montana, used to buy almost all the bulls my dad produced ( usually 12-15 bulls each year). I was pretty young yet, but I remember this man telling us some things we can visually see in our cowherds. One of the things this man said was that cows, that have not calved yet, who ride other cows in heat during the winter months will almost always have a bull calf. He also said that a portion of these cows that ride, will also allow other cows to mount them as if they are in heat themselves. Over the years, I have mentally kept track of cows that will ride other cows in heat, and most have had bull calves when they calve. There has been an occasional heifer calf but the large majority have had bulls. I have not seen as many cows allow other cows to mount them, but I have seen a few. I wish I had been old enough to remember many of the things this rancher had told us. One of the things he did, on one visit, was to walk through our cow herd and predict what sex of calf each cow was carrying. He used the color of the hair on the midline of the back of the cow as well as the swirl on top of her shoulder to make his predictions. When the cows calved, he had been almost 100% correct in his predictions.
Back in the 80s, one very cold day in early December I noticed a cow that was acting like she was in full blown heat. He had steam rising from her body from trying to ride other cows and allowing others to ride her. I thought she must have lost her pregnancy sometime in the fall. I did not get her shipped until 3 weeks later when she appeared to be in full blown heat again. It happened to be a sale day at the local auction mart so I decided to load her and take her to town. Also at this time, the manager of the sale barn had a pen in our feedlot where he assembled cattle that he had purchased. Six weeks after I had sold this cow, she showed up in the auction mart pen. She obviously had sold to someone who then sold her again 6 weeks later. When I noticed this cow in the pen, I also noticed that she was making udder and she appeared to be close to calving. I purchased this cow back and a few days later she calved with a very good heifer calf. This calf was our top selling female in our production sale that fall, selling at $4400 to a breeder in Iowa. I have often wondered how many other pregnant females I have shipped to market thinking they were open.