hereford bull

A Washington County Hereford bull in his “working clothes“. Having efficient and effective bulls is vitally important to having a successful breeding season. Before the breeding season begins, take the proper steps to ensure your bulls have the best possible chances to be successful.  Photo Credit: Mark Mauldin

The relatively mild winter climate in the Deep South offers cattlemen a fairly wide range of options in relation to the timing of successful breeding/calving seasons. The variation in systems makes the timing of this article a bit tricky, but there are a lot of bulls in this area turned out  from mid-February on through early Spring.

We talk a lot about managing the cowherd to help ensure reproductive efficiency, and that is incredibly important, but we can’t forget about the bulls. As the saying goes, it takes two to tango. While in relation to cows, there is a relatively small number of bulls on the ranch, their reproductive efficiency is just as important as the cows’ in terms of having a successful breeding season. It is important to emphasize efficiency, not just ability. We want as many cows as possible bred as early as possible in the breeding season, not after three or four tries or whenever Ole Joe the bull gets around to it. It is crucial to take the proper steps to ensure your bull battery has the greatest opportunity to be efficient, thereby giving your herd the greatest opportunity for a success breeding season.

A quick side note: Proper bull management is especially important on small operations. In large ranch settings,  bulls are turned out in groups, so if one bull is not up to the task, the others can help take up the slack. If you only have one bull, you need to do everything in your power to ensure that he is ready to go – your entire calf crop depends on his performance.

Steps to be Taken Before Breeding Season

Breeding Soundness Exam (BSE)

Before turn-out, a veterinarian should perform a Breeding Soundness Exam (BSE) on all breeding age bulls. As the name implies, a BSE is an exam specifically focused on evaluating a bull’s ability to successfully breed. The BSE will result in the bull being classified as satisfactory, unsatisfactory, or deferred. Unsatisfactory indicates a condition that impairs the bull’s ability to breed that is not likely to improve over time. Deferred indicates a condition that could improve over time, but the bull should be re-evaluated again later. I hope it goes without saying that unsatisfactory bulls should be replaced, and deferred bulls should not be depended on until the are deemed satisfactory.

In general, a BSE includes:

  • A general physical exam, looking for any visible conditions that would prevent the bull from effectively breeding
  • An in-depth evaluation of the reproductive system, again looking for anything that would substantially limit reproductive efficiency/ability. During the exam, scrotal circumference is measured; based on the bull’s age, there are minimum measurements required for the bull to be considered satisfactory.
  • An evaluation of a semen sample under a microscope. During the BSE a semen sample will be collected and the sperm in the sample will be evaluated based on morphology (size and shape) and motility (ability to move properly). There are minimum standards in place for both criteria that the bull must reach to be considered satisfactory.

The optimum timing of a BSE takes a little planning. The BSE should be performed as close to the beginning of breeding season as possible, but not so close that there is not time to find replacement bulls, if the BSE deems that a necessary step. Around 60 days before the planned start of the breeding season is the standard recommendation.

While not specifically part of the exam, during the BSE is also a convenient time for the veterinarian to collect a sample for a trichomoniasis test. Discuss the need for the test with your veterinarian, especially if you have brought in any new, non-virgin cattle (cows or other bulls) since your bulls were tested last.


I am not a veterinarian – discuss a pre-breeding vaccination protocol for your cow herd and bulls with your veterinarian. Some standard pathogens to consider vaccinating for include Leptospirosis, Vibriosis, IBR, BVD, PI3, BRSV, and in some cases Trichomoniasis. The vaccination protocol needs to be completed at least two weeks before the start of the breeding season. Depending on the products used and the specific situation, multiple doses of the vaccine(s) may be necessary. In these situations, there generally needs to be three or four weeks between doses. Two weeks before breeding season, four weeks between doses, it adds up in a hurry – talk with your veterinarian sooner rather than later to get a plan in place before you’re in a time crunch.

Body Condition Score

If a bull is working the way you want him to, he will lose a considerable amount of weight during the breeding season. To ensure that the expected weight loss does not impact his ability to breed cows in a timely manner, it is important to ensure that all bulls begin the breeding season at a sufficient Body Condition Score (BCS). A BCS of six is a good target for the beginning of breeding season. Evaluate your bulls’ BCS now. If they are below a six, additional supplementation is required. In this situation, be careful, increase the plane of nutrition gradually. Rapid, substantial changes in nutrition can cause a variety of problems. Give your bulls sufficient time to gain any needed condition.

New Bulls

If you have or are planning on adding new bulls to your battery this year, make sure you give the group time to sort out their hierarchy before the beginning of the breeding season. Bulls that are not accustomed to each other will fight to determine the hierarchy of dominance within the group, there’s not much to be done about that, except maybe fixing some fences after the fact. Give them several weeks to sort everything out before breeding season; when they are with cows they need to be focused on breeding, not fighting.

Another consideration relating to new bulls, if you are replacing a mature bull with a young/virgin bull, you should expect to see a drop in the number of cows serviced in a timely manner. This falloff is not guaranteed because there are tremendous differences in libido from bull to bull, but it should be taken into account when calculating the total bull power needed. Some general guidelines from Are Your Bulls Ready for Breeding Season by Glenn Selk:

The old rule of thumb is to place the young bull with about as many cows as his age in months. Therefore the true “yearling” would only be exposed to 12 or 13 females. If he is a year and a half old (18 months), then he should be able to breed 15 – 18 cows. By the time the bull is two years of age, he should be able to breed 24 or 25 cows. Realize that tremendous variability exists between bulls. Some are capable of breeding many more cows than what is suggested here. AND sadly enough, a few bulls will fail when mated to a very few cows.

Bottom Line – Don’t forget about your bulls.  Give thought to the steps needed to ensure your bulls are prepared for a successful breeding season well before turn-out. If you have questions or would like to discuss any of the points mentioned above in more detail, don’t hesitate to contact me or your county’s Agricultural Extension Agent. Also, check out the links below for more information on pre-breeding bull management.

Bull Management 101 for Breeding Season Success

Make Pre-Breeding Vaccines a Priority

Breeding Soundness Exam: A Risk Management Tool for Cow-calf Producers

Nutritional Management of Bulls

Feedstuff Considerations for Feeding Bulls 

Video: Understanding Common Reproductive Vaccines

Panhandle Ag Team Cattle & Forage Management Calendar