Many producers with spring calving herds just turned out their bulls. In the May Off the Hoof, we reminded everyone to subject their herd bulls to a breeding soundness exam (BSE). A BSE is the best insurance we available to ensure we don’t turn out a bull that is infertile or incapable of breeding cows. However, the BSE does not indicate if the bull is willing to breed cows. I was reminded of this very recently in the herd that I used for the “I bought a farm” YouTube video series. To get these heifers bred, we synchronized them for AI and then turned out a mature bull that had passed a BSE. When I inseminated these heifers, the weather turned very poor (middle of December) and the estrus response rate in the heifers was low, so I wasn’t expecting high conception rates to AI. Just to get an idea of how well we did, I spent some time in the pasture watching for return heats. As I expected, several heifers had return heats but what really stuck out was the bull was NOT breeding them. Some of the heifers were jumping on the bull and he seemed disinterested. I was concerned about the bull and told the owner that he needed to consider finding another bull. I could not assure him the bull was not getting the job done as research has shown that mature bulls will only breed a female in heat 1-3 times even though she is in heat for as long as 12 hours. This bull however showed absolutely no interest. For a variety of reasons, the owner decided to not get another bull. Pregnancy rates were only 61% in this group of heifers. The decision may have cost this producer significantly.
Bottomline: keep an eye on your bull to make sure he is working. Multiple return heats indicate a bull that is not getting females pregnant. If possible, replace the lazy bull. It will cost some money to make a switch, but this cost is likely much lower than the cost of open females.