Managing Young Bulls During Breeding Season

Producer Question from 2012

Q.  I start my breeding season in 30 days and have just purchased some young bulls. How should I manage the bulls? (May 21, 2012)

A.  Before the breeding season begins, a few simple management procedures involving the bulls can increase the likelihood of a high pregnancy percentage among the cows.

1) In multi-sire pastures, make certain that the bulls that will be pastured together have been in a common trap or pasture prior to the breeding season. Bulls WILL establish a social hierarchy. It is better to get this done before the breeding season begins rather than wait until they are first placed with the cows.

2) Put young bulls with young bulls and mature bulls with mature bulls. Mixing the ages will result in the mature bull dominating the younger bull completely, and in some instances causing a serious injury. If the plan is to rotate bulls during the breeding season, then use the mature bulls first, and follow with the yearling bulls in the last third of the breeding season. In this way, the young bulls will have fewer cows to settle, and will be 1 - 2 months older when they start breeding.

3) The cow to bull ratio is very difficult to decide upon. A conservative rule-of-thumb (for young bulls) is to place them with roughly the same number of cows as is his age in months. For example:

Bull age in months

  12 -15
  15 -18
  18 - 24

Number of females in breeding pasture

  10 - 12
  12 - 18
  18 - 25
  25 - 35

Some bulls are known to be successful breeding 50 or more; while some are failures with only 10 cows. Observing bulls early in the breeding season may give the producer a little idea of the libido and breeding capacity of the bull.

Dr. Rick Rasby Dr. Rick Rasby, Professor of Animal Science
Animal Science, University of Nebraska–Lincoln, Lincoln, NE