Maintain bull power during breeding season
By Grand Dewell and Patrick Gunn
Iowa State University
As cows and bulls are turned out to breeding pastures this summer, producers will expect their cows to be pregnant this fall. However, careful attention during the breeding season is critical to assure a successful production year.
For example, it’s critical that all bulls have a breeding soundness exam conducted prior to the beginning of the breeding season. However, a successful BSE at the beginning of the breeding season is not a guarantee that the bull will remain fertile throughout the breeding season. So remember to check breeding pastures on a daily basis to make sure that bull is doing his job.
Here are several things to look for when checking your breeding pasture this summer.
Bulls can incur feet and leg problems during the breeding season, which may limit their ability to breed cows. Foot rot is common problem that can cause lameness. Bulls will appear lame and may have swelling around the coronary band. If this is detected and treated early, bulls can return to normal but they will not be a very effective breeder while lame. Another common lameness problem, particularly in a multi-sire pasture, is leg injury associated with fighting other bulls. Lame bulls will not be able to travel sufficiently to find cows in estrus and if the lameness is in rear legs they won’t be able to mount a cow.
Bulls may also damage their penis or prepuce. Penile hematomas (or broken penis) results from an injury during breeding and can be very serious. Additionally, the bull’s prepuce can be lacerated causing swelling and inability to breed.
Other problems such as pinkeye will affect a bull’s ability to breed cows. If a bull is exposed to an infectious agent he may run a fever that is severe enough to damage sperm. Not recognizing a disease issue early on can lead to a devastating result in pregnancy.
In addition to watching bulls, it’s just as important to pay attention to cow behavior. Keeping track of how many cows are observed in heat will give some information on whether cows are becoming pregnant. If you notice more cows than expected are in heat later in the breeding season, then a problem may exist for either the cows or bull. Investigating issues at the right time will be more successful than trying to investigate six to nine months after the fact.
High temperatures also can affect the success of the breeding season. Because high temperatures have the ability to suppress hormones associated with both sperm and oocyte development, cows and bulls need access to shade (natural or man-made) during high temperatures. Make sure there is adequate fresh water and that bulls do not have to travel too far between water sources and where cows congregate.