• Cause: the exact cause of penile body deviations remains debated. Localized fibrosis after an earlier trauma to penile tissue as well as a weakness in the dorsal apical ligament are two postulated etiologies.
• Signs:
  • Deviation of the penis in a ventral or lateral/horizontal direction prior to intromission.
  • Indirect sign of females returning to estrus Estrus: signs and detection or poor pregnancy rate Fertility: analysis - key performance indicators.
• Diagnosis: close observation of the mating process is required to detect the abnormality. Intromission is disturbed.
• Treatment: depending on suspected etiology, either shortening of the convex side or strengthening of the dorsal ligament have been described.
• Prognosis: guarded – less than 1 in 4 bulls are likely to return to service.

Presenting signs

• Typically, only detected during detailed examination of a bull suspected to be sub-fertile or as part of a breeding soundness examination (where observation of mounting and intromission is performed).

Geographic incidence

• Recognized and described worldwide.
• Deviations involving the penile body, ie ventral or simple lateral, appear less common than those involving the free penile end (spiral) Free end penile deviation. The S-shape deviation appears to be less common still.

Age predisposition

• Most affected bulls have worked successfully prior to the deviation being diagnosed.
• The S-shaped deviation appears to occur in bulls at least 4 years of age.

Breed/Species predisposition

• No breed disposition confirmed.
• A hereditary/genetic component is not suspected.