Heat detection is more difficult in beef herds than in the close confines of a dairy unit.
Producers that use artificial insemination need to accurately identify cows in estrus.
Teaser bulls, commonly called gomer bulls, are useful in these circumstances. They identify cows in heat, but are surgically altered so they are incapable of impregnating them.
Teaser bulls must have a strong libido. Many producers make the mistake of choosing old bulls that are ready to be culled because they are no longer getting enough cows pregnant. Unfortunately, these individuals often have a decreased libido.
It is better to use young, vigorous, fertile bulls because they will be more sexually active.
It is also economically advantageous to use young teaser bulls. They will gain weight over the summer and can be sold before harvested feed is needed to maintain them.
Many people believe teaser bulls don’t remain sexually active for more than a year, so they should be culled from the herd after one breeding season.
Obviously, a teaser bull must not be able to impregnate cows. In some herds, it is also important that the bull be a non-entry teaser so it cannot spread venereal diseases. Venereal infections will not be a concern if the teaser is “clean” when arriving at the farm.
There are many ways to turn a bull into a teaser, each with its own advantages and disadvantages. Surgeons also have their own personal preferences.
A vasectomy is the simplest way. Though the bull can’t impregnate cows, it is still capable of intromission, so it can spread venereal disease.
A vasectomy is performed with a spinal anesthetic. A local block in the neck of the scrotum is an option.
The surgeon identifies the vas deferens, which is the tube that transports sperm from the testicles to the urethra, and removes a short piece.
The bull should not be used
as a teaser for at least 30 days because viable sperm may still be present in the upper part of the vas deferens.
An epididymectomy is a variation on a vasectomy.
An incision is made at the bottom of the scrotum, and as the testicle is squeezed, the epididymis, which is the duct between the testicle and vas deferens, protrudes through the opening.
It is separated from the testicle, tied off, and removed.
There are many kinds of penile surgeries that can be performed to prevent intromission. Two examples are diversion of the penis and removal of the penis.
In a penile translocation, the penis and skin that covers it is moved so that it exits on the outside of the flank fold.
The surgery is quite involved and there are reports of bulls learning how to gain intromission despite the abnormal placement of their penises. For this reason, a vasectomy is usually performed at the same time.
A penectomy, or penis removal, is another alternative. The same technique is used in bulls that are suffering from calculi, or bladder stones, stuck in the penis.
The urethra is cut open below the anus and sutured to the skin. The opening allows urine and semen to exit the body below the anus. The redundant penis is then removed.