Infertility in a cryptorchid bull: a case report

Area of Science:

• Veterinary Science
• Reproductive Biology
• Animal Science

Background:

• Cryptorchidism, the failure of one or both testes to descend into the scrotum, is a condition that can affect male fertility.
• Unilateral cryptorchidism in bulls can impact semen quality and reproductive hormone levels, raising questions about their utility in artificial insemination (AI) programs.

Purpose of the Study:

• To evaluate the reproductive potential and hormonal status of a unilateral cryptorchid bull maintained in an AI center for 3.5 years.
• To determine if retaining such a bull for breeding purposes is economically and biologically justifiable.

Main Methods:

• Collected and analyzed ejaculate quantity and quality over the bull's time at the AI center.
• Measured basal and stimulated plasma testosterone concentrations at various life stages.
• Performed post-mortem histological examination of both testes and measured tissue testosterone concentrations.
• Compared findings with control bull calves.

Main Results:

• Over 53% of ejaculates were discarded; only 2% were of excellent quality.
• Hormonal analysis indicated impaired steroidogenesis compared to controls.
• The retained testicle showed no spermatozoa, Sertoli cell degeneration, and fibrosis.
• Testosterone levels were higher in the scrotal testicle parenchyma but lower in its epididymis compared to the retained testicle.

Conclusions:

• The unilateral cryptorchid bull demonstrated significantly reduced semen quality and impaired testicular function.
• Histological findings confirmed the lack of spermatogenesis in the retained testicle.
• No justification was found for maintaining this bull in an AI center for breeding purposes due to its compromised reproductive capacity.