Bovis ISSN 2398-2993

Testicular degeneration

Contributor(s): Jonathan Statham , Paul Wood

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Introduction

  • Cause: various.
  • Signs: the presence of one or two small testes, and reduced fertility performance.
  • Diagnosis: physical examination of the testes and collection and examination of semen.
  • Treatment: dependent on underlying cause.
  • Prognosis: testicular degeneration can be temporary or may result in permanent reduced fertility or infertility.

Pathogenesis

Etiology

Predisposing factors

General

  • Over conditioning of pedigree bulls is common prior to sale and subsequent more harsh commercial herd conditions may be associated with testicular degeneration.

Pathophysiology

  • Scrotal sac disruption:
    • One of the main functions of the scrotum is temperature control.
    • Any disruption to this can interfere with spermatogenesis Sperm: spermatogenesis.
    • Whilst external weather conditions are capable of insult and can affect sperm quality, it really requires significant trauma, severe skin infection, allergic reaction and scrotal edema, a scrotal hernia or variocele to result in serious infertility.
  • Fat deposition in the scrotal neck from over conditioning may interfere with countercurrent heat exchange mechanisms and so precipitate degeneration.
  • Orchitis/epididymitis Orchitis and epididymitis:
    • Infection may commonly involve one testicle, causing elevated temperature and damage to the spermatogenic epithelium.
    • However inflammation can also interfere with the temperature gradient of the whole scrotum and indirectly affect spermatogenesis of the second testicle.
  • Systemic illness:
    • This can affect spermatogenesis in three ways:
      • Pyrexia may result in disruption to the temperature gradient of the scrotum.
      • Toxic agents may result in damage to the spermatogenic epithelium.
      • Systemic illness may interfere with the hormonal mechanism which control spermatogenesis.
    • Illness may result in a temporary or permanent reduction in fertility.
  • Pharmacological agents:
    • Anabolic steroids, administered to young bulls, can result in reduced testicular size and delayed development of seminiferous tubules and interstitial cells, causing a delay in puberty.
    • By inference, treatment with corticosteroids may also be likely to affect semen quality short term.
    • There is evidence that some NSAIDs may also have an effect Anti-inflammatory drugs: overview.

Timecourse

  • Degeneration may occur over weeks to months and be inapparent in the initial stages.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Statham J M E (2010) Differential diagnosis of scrotal enlargement in bulls. In Practice 32, 2-9 VetMedResource.
  • Penny C (2009) The development of a UK bull breeding soundness evaluation certificate. Cattle Practice 17, 64-70 VetMedResource.
  • Eppink E (2006) A survey of bull breeding soundness evaluations in the south east of Scotland. Cattle Practice 13, 205-209 VetMedResource.
  • Penny C (2005) Practical semen collection and examination techniques for breeding soundness evaluation of bulls. Cattle Practice 13, 199-204 VetMedResource.
  • McGowan M (2004) Approach to conducting bull breeding soundness evaluations. In Practice 26, 485-491.

Other sources of information

  • Chenoweth P (2015) Bull Health and Breeding Soundness. In: Bovine Medicine. 3rd edn. Wiley-Blackwell Publishing, Oxford.  pp 246-261.
  • Logue D N & Crawshaw W M (2004) Bull infertility. In: Bovine Medicine – Diseases and Husbandry of Cattle. 2nd edn. Wiley-Blackwell Publishing, Oxford. pp 594-626.
  • Entwistle K & Fordyce G (2003) Evaluating and reporting bull fertility. Australian Association of Cattle Veterinarians, Brisbane, Australia.


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