Persistent Frenulum in Bulls

Persistent frenulum in bulls is a congenital defect in which the frenulum, a band of connective tissue that normally regresses by puberty, abnormally persists between the glans penis and the prepuce (sheath). This condition interferes with normal penile extension and prevents successful breeding due to ventral deviation of the penis during erection.

The frenulum is a collagenous band of connective tissue present at birth and attaches the glans penis to the penile section of the prepuce.

The attachment should begin to break down by 4 weeks of age and separation should be complete by 8 to 11 months of age.

Persistence of the frenulum attachment beyond 11 months of age is considered pathologic

When this thin band of collagenous connective tissue fails to rupture the penis can extend, but the persistent frenulum deviates the tip of the penis ventrally and may prevent intromission.

A persistent frenulum is a band of tissue from the median raphe at the posterior of the glans penis to the prepuce. This epithelium-covered band varies in width and thickness and usually contains one or more blood vessels.

Surgical Procedure

• A persistent frenulum can be repaired surgically and the resection of a persistent frenulum can be performed with the bull standing or recumbent.
• Surgery of small frenula is done with the bull standing and after injection of a local anaesthetic and for large frenula after general anaesthesia.
• The bull should be held off feed for 12 hours before surgery and sedated with xylazine hydrochloride (0.05 mg/kg body weight intravenously) and acepromazine (0.03 mg/kg intravenously).
• The penis is extended and the frenulum grasped at its attachment to the penis and prepuce.
• By ligating each end to reduce the possibility of haemorrhage, the frenulum is resected using Mayo scissors.
• Bleeding is usually minimal, but may be controlled using electrocautery or suture ligation.
• The bull should be rested for 14 to 21 days before breeding activity is resumed.
• The condition is inherited and strongly suggests a simple autosomal recessive pattern.