Best Way to Get Your Bulls Ready for the Breeding Season

By Peter Vitti

Beef bulls are prepared in a few ways prior to the upcoming breeding season. Some bulls are ignored, maybe left on some distant stubble field or in a drylot pen; inadequately fed. Some bulls are fed too well, so they waddle with fat. Yet, the remainder are properly prepared for the breeding season. In this way, it puts them in the best body condition that promotes good fertility, which gets their cowherd in calf.

Whether these successful bulls are young or mature, they must maintain or achieve a body condition score (BCS) of 5.0 – 6.0 (thin = 1 and 9 = obese) by the breeding season. That’s because beef bulls in this optimum body condition have the highest viable sperm count and have high sexdrive. To gain an even better premium on fertility, we should also segregate the young first-year bulls and returning two-year olds from mature bulls and put them on their own feeding program to gain weight into maturity.

For example, if a group of herd mature bulls weigh 2,000 lbs.; we want yearling bulls to weigh about 1,300 lbs. (65% of mature wt.) and two-year olds weigh about 1,500 lbs. (75 – 80% of mature wt.) at the beginning of the breeding season. Such growth rate of the yearlings will largely be based upon their adjusted autumn-weaning weight, while two-year bull performance depends upon weight-loss recovery at the end of their first breeding season. In both cases, this weight-gain is estimated to be about 2 – 3 lbs. per head, daily.

Case-in-point: I have a friend that operates a 250 cow-calf operation that calves out them in mid-March to the end of April. Bulls are released onto breeding pastures in early June and pulled by the end of July. (Note - A few weeks before the main cowherd is bred, calving-ease bulls are released to breed his 1st calf replacement heifers).

At the end of the last year’s breeding season, all bulls were separated according to stage of maturity by putting them on their own recovering hayfields, until the first snowfall. Then, they were brought onto pastures near my friend’s home and overwintered on harvested forages, concentrates and a good mineral-vitamin program.

About a few months before the present 2023 breeding season, here are some dietary and related details on how; my friend ensures all his bulls are ready to breed when the time comes:

1. Body condition of the bulls (as well as the entire cowherd) is evaluated. This allows time to increase the plane of dietary energy of all mature and young bulls, whether to put back some BCS or increase the rate of growth.

2. A mid-winter inventory of available forages is taken. Last winter, there was a feed shortage due to the previous summer-fall drought, which put my friend’s bulls (and cows) in less-than-adequate shape and fertility. This winter, there is an adequate supply of good quality alfalfa-grass hay, and barley silage.

3. Mature bulls (3 years old and older) in fairly good shape are maintained diet of 58 – 60% TDN and 12 – 14% crude protein. Yearlings and returning two-year olds are moved to achieve optimum BCS by consuming a higher plane of 62 – 65 % TDN and 13 - 14% protein.

4. Actual pre-breeding diet is really an extension of the overwinter program; mature bulls are fed alfalfa-grass hay, plus 5 – 10 lbs. of barley silage. Yearling bulls and 2-year- olds get 30 lbs. of barley silage plus a couple pounds of barley. Plus, when weather gets cold and nasty, the dietary energy is increased – mature bulls may get a few pounds of barley added to their all-forage diet.

5. A fortified mineral/vitamin program is introduced to all bulls at the same time of their pre-breeding bull diet. My friend provides them with a breedertype mineral fortified with chelated (more bio-available and retained) trace minerals as well as higher levels of vitamins A, D and E. He likes to refer - to a classic KSU study that fed zinc-methionine rather than regular zinc to breeding bulls, which resulted in a 33% increase in sperm production.

Right now, the BCS of most of my friend’s bulls are in optimum body shape for successful breeding. He is therefore optimistic about the 2023 breeding season - high-fertile bulls yield high-conception rates throughout his cowherd. And each pregnant cow will eventually go on to give birth and