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Published on: October 11, 2019

Written by Dr. Pat Comyn

I have recently had a client ask me what his options were with a holstein bull calf of very high genetic value (genomic prediction) that happened to be a unilateral cryptorchid. Aside from a grunt, I didn’t know how to answer, so I thought I should educate myself. As it turns out, the causes of crytorchidism in cattle aren’t  very well understood. A some observations from some reading.

  1. The left testicle is most commonly affected.
  2. Male repro tract development occurs from a different tissue (wolffian duct which is part of the mesonephros developing into the epididymis, vas deferens, seminal vesicle, and ejaculatory duct) than the female tract (Müllerian duct which differentiates into vagina, cervix, uterus etc).
  3. While many argue that chryptorchidism is “heritable”, the heritability of this trait is not well characterized meaning that we don’t know what percent of the development of cryptorchid syndrome is truly genetic and what percent is environmental (meaning uterine / maternal hormonal influence).
  4. This is an excerpt from Cryptorchidism and associated problems in animals1 R. P. Amann2 and D. N. R. Veeramachanen: Animal Reproduction and Biotechnology Laboratory Colorado State University, Fort Collins, CO 80523-1683 USA.

“Early reports on cryptorchidism (e.g., de Graaf, 1668) provided evidence of two or more diseases, because undescended testes are not located at a common non-scrotal site. Nevertheless, the general perception had been that cryptorchidism is a single disease with moderate heritability, incomplete penetrance, expressed only in males (sex specific expression), and concentrated by inbreeding or minimized by culling affected males and all siblings. However, the notion of a single-locus gene problem gave way to acceptance of a polygenic recessive model, based on relatively small studies with pigs (Sittmann and Woodhouse, 1977; Rothschild et al, 1988) and dogs (Cox et al, 1978; Nielen et al., 2001); also data for men (Czeizel et al., 1981). It is evident that abnormalities in >20 genes are associated with human cryptorchidism (Klonisch et al., 2004) and, currently it is accepted that cryptorchidism has many causes including genetic, epigenetic, and environmental components.”

  1. A search on line showed no studies where back breeding of cryptorchids to dam or siblings had been done to characterize heritability coefficient.
  2. A unilateral cryptorchid will on average produce 60 – 80% the spermatozoa of a normal bull.
  3. The affected testicle should be removed so not to place abnormal spermatozoa in the ejaculate. Too, removal will enhance hypertrophy of the normal testicle.

So here we are. A unilateral cryptorchid dairy bull calf. The owner vents his / her frustration and also inquires as to your thoughts on how to proceed. Here are my thoughts…

  1. If a dairy bull and high enough genomics, offer him out. There are dairy bulls in collection now that are unilateral cryptorchids.
  2. Consider private CSS EU qualified collection then see if the semen can be purchased by a bull stud and sold.
  3. Like point B except the producer sells the semen.
  4. The money might not be as good as a normal bull purchase but one can make lemonade from lemons.
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