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Bulls: A valuable part of your operation

You spent hours flipping through the sale catalogs finding the right bull, or set of bulls, that best fit your operation’s goals. You made the purchase, and now the bulls are all settled in at home. But wait, the work isn’t over just yet!

When it comes to managing bulls, we often compare them to athletes. Top athletes prepare in the off-season to perform their best when it matters most. Your bulls should be prepared throughout the year to be ready to perform when we expect them to do their job of covering cows during the breeding season. To maximize their genetic potential, prepare your bulls now by:

  • Evaluating their nutritional needs
  • Focusing on achieving ideal body condition
  • Providing mineral and vitamin supplements for optimal fertility


It is not uncommon to hear cases of bulls losing condition after they are brought home. While various rations are used to develop bulls, some type of a high concentrate ration is typically fed to determine the growth potential among their counterparts of yearling bulls. In these situations, it is important to adjust bull rations gradually from a high-energy ration to a forage-based diet or what you will feed them. An abrupt transition could result in increased stress, digestive disturbances, body condition and, ultimately, poor fertility.

Body condition

Bulls should be fed and managed based on their condition. If condition changes are necessary, these adjustments should be made gradually for the longevity of the bull, instead of making drastic changes either pulling weight off or putting weight on a bull. Body condition scores (BCS) should range from 5.5–6.5 on the 9-point scale. The ideal condition will depend on the age of the bull, number of cows expected to cover, length of breeding season and other factors. Body condition should be assessed throughout the year to best manage bulls and their nutritional needs. If bulls have excess condition after purchase, they may need to lose fat and add muscle prior to breeding. It is crucial, however, that they are still gaining weight and growing, but their condition is reduced slowly to avoid issues.

Minerals and vitamins

In addition to protein and energy, minerals and vitamins also play a critical role in bull fertility through spermatogenesis and can impact semen quality. Minerals and vitamins such as phosphorus, copper, zinc and vitamin A directly affect in fertility and often need to be supplemented due to lower levels available in forages.

We have continued to see and hear about the success Bioplex® organic trace minerals have in the cow herd with Blueprint®. While current published research on the bull side is more limited, it also looks to be beneficial to performance. In a study done by Kaehler et al. (see figure below), bulls were supplemented with inorganic minerals and collected, on average, 412 straws of semen per collection day. After the bulls were switched to a mineral with organic trace minerals, an average of 608 straws were produced per day primarily due to an improvement in transmittance percentage, meaning samples collected had a higher sperm count. If we were selling semen at $20/straw, with roughly 200 more units, we are looking at an additional $4,000 per day gross revenue by switching to Blueprint. Even if not collecting bulls or selling semen, this shows the increase in breeding potential bulls would have if live breeding a group of females and the positive impacts minerals and specifically the source of minerals, have on bull fertility.




Bulls contribute more than we probably give them credit for in an operation. We need to ensure they are getting the attention they deserve during the off-season by providing vital supplements to meet their nutritional needs. To help maximize the return on your investment, give the bulls the most premium nutrition formulated for today’s genetics. If protein supplementation is necessary, look for the CRYSTALYX® Blueprint® 20 AN or 30 options. If mineral and vitamin supplementation are all that is needed, look towards the CRYSTALYX Blueprint 6% Phos options. Remember, feed-through fly control is also an effective management tool during the breeding season, so bulls can do what they are meant to do and meet your production goals. Both the Blueprint 20 AN and Blueprint 6% Phos blocks are available with ClariFly® for control of horn, face, stable and house flies.