When Should I Semen Check my Bulls?

Every spring, those bulls that have been freeloading for the past nine months finally get to earn their keep by going out to pasture to breed cows. To make sure they are up to the job, we must semen check these fellas before turnout. Otherwise, they may still be freeloading, yet this time it costs you a lot more money. Knowing a semen check needs to occur is one thing, knowing the best time to do it is another.

Check after March 31st
While a semen check aids in identifying problem bulls, it is only a snapshot in time. A bull could pass with flying colors one day, and then injure his penis the next, rendering him worthless. Therefore, it is best to perform the examination after the most likely period when injuries occur to the testicles.

The cold, wet weather of March is tough on bull testicular health. These conditions challenge the temperature regulation ability of the bull’s reproductive system. Because of this, for commercial cow/calf producers it is best to wait until April to semen check your bulls. This way injuries that occur in the cold will be evident at the time of the exam.

Give yourself time to find a replacement
On the other hand, waiting too long presents issues as well. The biggest concern is when a producer waits to check their bulls until the day of turnout. At this point, finding a replacement becomes an emergency. Because most producers start breeding cows in roughly the same two months, those scrambling to find a replacement bull are doing so with everyone else who waited until the last minute. You will not likely find the quality you are looking for in bulls at this point in the buying season either.

Rather than waiting, check bulls at least two to three weeks before turnout. This provides time to find a replacement bull if necessary. Keep in mind that some bulls may fail their first semen check, yet simply need to be “cleaned out” for the spring and pass their second check. Your Sioux Nation veterinarian can let you know if the abnormalities present are likely to clean up on a second test.

Be early enough for vaccines to work
The second reason to test at least two to three weeks before bull turnout is the efficacy of the vaccines we often administer during the semen check. All vaccines require time to become effective, and that period is usually around two to three weeks. Also, some vaccines can cause a temporary decrease in fertility. This is due to a small immune response to the vaccine, which is normal and necessary. While this may not cause a major issue, if it leads to one cow not settling first cycle, you lose the 21 days of gain her calf would have had next year.

No matter when you start breeding cows, it is best to check the bulls between two to six weeks before the turnout date. Being a planner and having seen my share of last-minute bull shoppers, I tend to recommend people schedule the exam early within the six-week time frame. Yet even if you get behind and need to turn them out on pasture today, it is still best to semen check those bulls. It is much less expensive to learn they have a problem in May than realize it at preg check in November.