Cattle Genetics – Testicle Size and Shape 

There is a lot of debate about testicle size and shape of a beef bull. Is bigger better? What are the minimum requirements for circumference? How about how they hang? One hangs lower than the other, what does that mean?

There is also a lot of research that has gone into testicle size and shape. Gerald Fry has extensively been researching the subject for a long time, and has written a book on the subject, in addition to his website, which has a lot of great information on cattle genetics.

I think that Gerald Fry brings up a lot of good points about cattle genetics. I agree with him on most of them. However, could there be something more (or less) to shape and size of the testicles?

While talking to South African rancher Ian Mitchell-Innes, who if you don’t know already I’m doing an internship with right now, he made an observation about herbivores in wild. One day he noticed what the testicles looked like on wild male herbivores. The testicles on these animals are hard to see, because they are smaller. The most important characteristic is the fact that they are shaped like a cylinder. Why are they  shaped like a cylinder? Predators. They can’t run fast enough if they have large testicles, the Lions will eat them! Their “package” needs to be slim and trim. Interestingly this seems to directly contradict Gerald Fry’s observations and research over the last 30 years!! Ian’s cattle also have a similar testicle size and shape as the wild herbivores.

So, who is right? I don’t think anyone is “right.” However, there is a lot to be said for animals in the wild who all share the same cylindrical scrotum shape. As I mentioned, Ian’s cattle also have a scrotum that is cylindrical shaped. He has very good reproduction and herd fertility. The answer lies, in my opinion, in the environment into which the livestock are in. Domesticated cattle in the United States can obviously have a larger scrotum and testicles. There are no Lions, Wild Dogs and Hyena.

While I’m not trying to discredit Mr. Fry and the research he’s done over the last 30 years, it’s interesting to note that cattle and other herbivores can have a testicle shape and size that is contradictory to what we have thought. So what should you do as a cow/calf producer? Keep doing what you are doing, but take note of the fact that we don’t have all the answers. Domesticated cattle in the United States are different and consequently for those of you back home (the US) taking his research into serious consideration is a good idea.

What do you all think of this interesting contradiction? Have you noticed a difference when it comes to testicle size and shape in your herd’s fertility?

Chris Stelzer

Chris Stelzer is a published Author, founder of Agricultural Insights and creator of many resources that help family farmers and ranchers grow their businesses. His flagship courses are the Grazing Mastery Program and The Farm Marketing Mastery Program. 

Chris Stelzer

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