Signs of testicular degeneration

SIGNS OF TESTICULAR DEGENERATION

They are similar in all species of animals and range in degree from mild to severe depending upon the cause and duration of the degeneration.

The fertility

  • In the male with testicular degeneration may vary from slightly reduced conception rates to moderate to severe infertility to complete sterility.

The size of the testes

  • It is usually reduced from normal to about one-half to two-thirds of its normal size depending on the duration and degree of atrophy of the seminiferous tubular epithelium.
  • In acute orchitis, inflammatory conditions, obstruction of the efferent ducts, or testicular tumors, an increase in testicular size is usually noted.

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The consistency of the testes

The tonometer is useful for the objective measurement of testicular consistency.

  • The tonometer test correlated closely with other tests of semen quality.
  • Bulls with soft testes tended to produce fewer sperm cells.
  • Acute orchitis is characterized by a tense swelling and enlargement of the testis accompanied by pain and heat. This should be differentiated from hydrocele or hemaotcele.
  • Chronic degeneration and atrophy of the testes especially in older males is characterized by fibrosis of the testes often with calcification. Fibrotic testes are hard, firm and often lack tonicity or elasticity.
  • Ultrasonics can be of value in the detection of connective tissue in fibrosis of the testes.
  • Testes containing tumors may be enlarged and have an irregular shape and consistency on palpation.

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The libido or sex drive

  • It is usually not related or associated with testicular degeneration except in acute orchitis or other painful testicular diseases or in testicular atrophy associated with severe debility or inanition due to a variety of causes
  • Leydig cells are much more resistant to stress factors than the cells of the germinal epithelium

The semen picture

Points to be cosidered

  • It is very helpful in diagnosing testicular degeneration.
  • Semen may be collected by the artificial vagina, by electroejaculation or other methods.

Since it requires about 60 days or more for sperm cells to develop from spermatogonia until they are ejaculated, it may be desirable in diagnosing testicular degeneration to take several samples at weekly or greater intervals.

  • The semen production and quality in young immature bulls continues to improve in motility, concentration and morphology for months after puberty is reached so if an initial semen sample is poor, subsequent samples are indicated.
  • The first semen samples taken after a long period of sexual rest may also be misleading as these are often of poor quality with many dead spermatozoa.
  • In males where testicular degeneration is severe, semen quality is usually poor.

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Sperm cell concentration

  • May be reduced to one-third to one-half of normal values or show severe oligospermia or azoospermia.
  • Watery translucent semen is common in affected bulls and rams.

Sperm cell motility

  • It is reduced one-third to one-half or more due to an increase in abnormal cells, dead cells, necrospermia, or poorly viable cells.
  • The duration of motility after ejaculation is shortened.

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Sperm cell morphology

  • After staining it reveals an increase in abnormal heads, tails and middle pieces.
  • The degree of change in the morphology of cells may vary from normal semen which usually contains from 5 to 15 per cent abnormal cells, to a 15 to 20 per cent increase in abnormal cells, to a 15 to 20 per cent increases in abnormal cells in mild cases of testicular degeneration, to a 20 to 30 per cent increase in moderate testicular degeneration, and to a 35 to 60 per cent or greater increase in severe testicular degeneration.
  • The occurrence of large numbers of primary abnormalities that arise during spermatocytogenesis or spermatogenesis and early spermiogenesis are more indicative of a severe testicular degeneration than the presence of secondary abnormalities that occur late in spermiogenesis or during storage of spermatozoa in the epididymis.

The appearance of primitive cells such as giant cells and spermatocytes with restitution or pyknotic nuclei together with a marked reduction in sperm cell concentration and motility are signs of severe degeneration of the testes.

  • Testicular biopsies may be of value in certain species such as the dog and horse but are impractical for technical reasons in the bull.
  • Furthermore the above signs and additional tests of sequential semen samples will accurately reveal the relative degree of testicular degeneration.

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Last modified: Monday, 4 June 2012, 9:45 AM