The 2012 fall breeding season is nearly here. With the high input costs of keeping each cow, it is vital that a high pregnancy rate occurs during the upcoming breeding season. Obviously, bulls represent one-half of the factory that will produce a calf crop to sell next year.
A good manager keeps an eye on his bulls during the breeding season to make sure that they are getting the cows bred. Occasionally a bull that has passed a breeding soundness exam may have difficulty serving cows in heat, especially after heavy service. Inability to complete normal service and low fertility are more prevalent and therefore more detrimental, than is low libido (failure to seek out and detect cows in heat) to calf crop percent. Such problems can best be detected by observing bulls while they work. Therefore producers should (if at all possible) watch bulls breed cows during the first part of each breeding season. Take a thermos of hot coffee at dusk or dawn’s early light and watch from the cab of the pickup to see if the bull(s) are doing the job for which they were purchased. If problems are apparent, the bull can be replaced while salvaging the remainder of the breeding season and next year’s calf crop. Likewise a small proportion of bulls can wear out from heavy service and lose interest. These, too, will need to be replaced. The greater the number of cows allotted to each bull in the breeding pasture the more critical it is that every bull be ready to work every day of the breeding season.
Injuries to bulls during the breeding season are relatively common. When a bull becomes lame or incapable of breeding, because of an injury to his reproductive tract, he needs to be removed from the breeding pasture and replaced with another bull.
Proper cow to bull ratios are difficult to define. There is tremendous variation among bulls as to their capability to breed large numbers of females. Recommendations for smaller herds that will utilize only one bull per pasture may need to be conservative. A time honored rule-of-thumb is to place about the same number of cows or heifers with a young bull as his age is in months. For instance a bull that is 14 months old going into his first breeding season should be expected to breed 14 or 15 cows; whereas as a two-year old bull may be placed with 20 - 25 cows. Mature bulls that have been examined by a veterinarian and have passed a breeding soundness exam can be placed with 25 - 35 cows and normally give good results.