Testicles

[denny10012]

Might sound like a funny question but " Does the size of a Stallions testicles determine his fertility "

 

[Lindi-loo]

In a word "NO"

 

[Miniv]

Nope.

 

[Lizzie]

For several years now, we in Gypsy Horses, have been researching the possible link between small testicles and the inability to get mares in foal reliably. We absolutely have found a link. Several horses who seldom got mares in foal or maybe just one, even though breeding quite large mare herds, were seen to have small testicles. We also think the problem is genetic. One very famous stallion in the UK, consistently failed to produce more than one or two foals over a number of years. His one known son, who came to the US, also produced only one filly in the UK and none since coming here. Both had very small testicles and low sperm counts when tested. Another Gypsy stallion with small testicles has also failed to produce at all. He is now gelded.

We have discussed the problem a great deal on our forum, so, while it might not be true in all cases, we do think there is a link

Lizzie

 

[bluerogue]

I had a vet tell me once that size does matter. But not a great deal. He had a big, long explanation, and it's been several years since I had Houdini gelded. I don't remember everything that he said. He also said that genetic capability plays a role, and that will trump size. So if you have a stallion who has big... jewels... but low genetic capability, he will still be a low producer. And the reverse is true also, if your stallion has small jewels, but high genetic capability, he will produce high volume of swimmers.

So, to answer your question, size doesn't really matter in the long run! It's more of a case by case basis. Even in bloodlines, there is great variability. If there is a question about a particular horse, just get him tested.

 

[Matt73]

Nope. As long as there are testicles and they're not atrophied (from disease etc.) and are producing sperm, size doesn't matter.

 

[Jill]

My official answer is NO. I don't want to see any additional "one-up-manship" between Destiny & DunIT

 

[valshingle]

I disagree. I have been told, several times, by both canine and equine vets that the bigger the testicles, the more sperm the stallion produces. So while size may not make a huge difference, it does affect the number of sperm a horse produces. I believe this can make a significant difference in how fertile a horse is for AI.

 

[Becky]

I agree with Val. My vet has said that testicular size directly affects fertility in a stallion. While I have had stallions with relatively small testicles get their mares in foal, the ones with larger testicles seem to have better luck getting the mares in foal with less breedings through fewer heat cycles.

 

[Matt73]

I disagree. I have been told, several times, by both canine and equine vets that the bigger the testicles, the more sperm the stallion produces. So while size may not make a huge difference, it does affect the number of sperm a horse produces. I believe this can make a significant difference in how fertile a horse is for AI.

Nope. You can have a huge set that produce very little or no sperm and vice versa. The Grand Prix jumper Cumano has a humungous pair and is well known for having poor quality/low quantity sperm.

 

[shorthorsemom]

Don't know if it is urban myth or not, but the smaller testicles hang closer to the body and are warmer and warmer equals less sperm. I do know that testicles that do not descend are absolutely tiny little things, the warmth and inside the body equals smaller testicles. So maybe the smaller ones do produce less because of warmth???

 

[Gilly]

I had a colt gelded and the vet was very interested in the fact that one of the testes was slightly malformed. It was clearly evident when she drew my attention to the difference between the normal one and the malformed one as they were placed side by side. This would definitely have made a difference to his fertility if he had been left entire but would not have been evident by external examination - even by a vet. The vet said the malformed teste would not have produced sperm or if it had, certainly in greatly reduced volume. So I would assume that there must be studs with minor malformations that are not visible - who are producing foals but perhaps with a greater rate of returning mares that 'normal' studs.

 

[rubyviewminis]

This article should answer all questions. My vets have always told me the same thing.

http://archive.ctba.com/01magazine/mar01/images/infert.pdf

 

[Genie]

I have only heard that they should be similar in size. I Don't want to be an expert on testicles

:OKinteresting

 

[valshingle]

Nope. You can have a huge set that produce very little or no sperm and vice versa. The Grand Prix jumper Cumano has a humungous pair and is well known for having poor quality/low quantity sperm.

As noted in the article, there are many variables that go into a stallion's fertility. I had one stud dog that had chronic sporadic motility and low sperm count problems. His definitive diagnosis (on necropsy) was that he had chronic inflammation of the testes, probably from a low grade infection at some point. As long as there is nothing else going on, a stallion with larger testicles will produce more sperm than a horse with smaller testicles.

 

[StarRidgeAcres]

I only have my own, and limited, experience to reference. Corona had small, different sized testes. I had his fertility tested. Lots of sperms, low number of irregular ones, fast movers (sorry, don't remember the medical terms) but I bred him to probably 6 mares and only took. Of course in hindsight that was a blessing.

Pete's entire "package" is huge!lol. People always comment on it. Makes me wonder if it's nature's way of compensating for his tiny body size. He successfully bred a 34" mare this summer. Just a thought.

Spirit on the other hand has two large, even-sized

ones and he can look at a mare and get her in foal!

 

[REO]

I don't want to see any additional "one-up-manship" between Destiny & DunIT

No kidding! Last thing I need is Nort & Pooka comparing boy berries!

I've always heard that bigger ones have more sperm volume.

But of course there are individual circumstances like illness, genetics etc.

 

[SampleMM]

Well, I find this very interesting........ I had a stallion that had very small testicles but after I bred him they got huge. He was able to get multiple maiden mares bred and one mare that hadn't taken for two years straight after a very rough delivery. Any thoughts on enlarging after their first sexual experience?

 

[valshingle]

I am only guessing, but

1) Could it have been age? Meaning was he young when they were smaller and he just matured over time?

2) Hormones. I imagine that breeding and being with mares in season caused some hormones to be secreted. Perhaps that continued stimulation caused increased hormone release which in turn caused an increase in testicle size. I just did a google search on this subject, but most of the articles were not exactly scientific, lol! I guess that's what happens when you type in 'testicles enlarge after sex'!!!

 

[Lindi-loo]

Have to remember it only takes 1 sperm to fertilise the egg..so even if the testicles are huge it has no relevence to how many they produce and if they carry more sperm or not..it really does depend on sperm count..a pony with a small pair with a high count can obviously carry as many as a pony with a large pair with a low count..but still only takes just 1

..a pony with a malformed testicle or a stallion bred from a stallion that had problems with fertility to begin with is surely going to have a genetic chance of poor fertility himself so thats a different matter all together