Stallion potency as they age?

[wgc517]

I was looking at Not for Love (sire) for one of my mares but he is 20 years old. My question is does a stallion lose some of their genetic traits to transfer as they get older. Does a stallion transfer the same amount of traits when he is 8 as when he is 20?

thoughts?

[ElPrado]

The genetic material remains the same. He may produce less sperm, due to his ability to produce sperm failing.
Mutations have been known, but that would be extremely rare.

[xfactor fan]

Maybe, maybe not.

Sperm production has a fast turnaround. In a perfect world there would be no changes in the chromosomes and genes during each cell division.

However once a change has been made, it will be handed down in each cycle of cell division and will be in each sperm produced from that cell line.

Cell divides into two. One then splits again, sharing half the chromoses from the parent cell and turns into a sperm.

The left over cell that didn't become sperm now spints in two again, with one cell becoming two sperm cells. And the cycle continues.

As a male ages, the chances of cell damage increases, which ups the chance that changed cells will make it into changed sperm cells.

However there are lots of sperm cells produced, so the chances are slim that a changed cell will actually end up fertalizing a egg are slim.

Hope this helps.

[wgc517]

thank you for the very informative information. It is great to have such knowledgeable people on here. I appreciate it.

[Dave C]

There are two issues to your original question, fertility and the ability to sire top quality foals. I don't think you are asking about fertility. The ability to sire top quality foals is debated. Most sires will show a noticeable decline in the number of stakes winners as they age. There have been a few notable exceptions such as Northern Dancer but the exceptions are rare. The reason for this decline is what is debated. As a sire becomes proven the types of mares that he is sent tends to change which may cause some of the decline such as when a proven sire is sent unproven mares to upgrade them. Another possibility is that there is a correlation between the sires health and the vitality of the sperm that he produces. There is evidence through multiple species to suggest that the health of the sperm affects which genes are active in the resulting embryo. It is an unavoidable consequence of life that stallions and mares accumulate asymptomatic mycoplasmic infections as they age that may contribute to the declining performance of the foals that they produce as they age. The cause of the observed decline is not proven, continues to be studied by researchers and pedigree people, and in the end should not be a deciding factor in a breeding decision unless you are only breeding for a champion. The offspring of proven stallions continue to perform as good solid horses that can pay their bills and their daughters are often amongst the best producers a sire will have as a broodmares sire.

[wgc517]

Thanks Dave C, that was also very helpful...

[kimberley mine]

Something else to consider:

* A stallion who is not top class may have mare owners go to younger, more fashionable stallions. Since he is breeding lesser quality mares, his production stats may decline.

* A stallion who hits very strongly with a particular bloodline may have reduced access to that bloodline as he ages. Cozzene is a great example: he loved son strains of Ribot, and as the Ribot sireline diminished and the mares bred on that pattern aged, he got fewer top-class stakes winners.

Not For Love, however, is Mr P over ND, and so he is unlikely to have that problem. He is also the best stallion in Maryland and has been for a long time, so the likelihood that mare owners will start going to other fashionable stallions is lower.

[tbrace]

All I know is, as stallions get older, they have fewer great foals. Why? Many reasons probably.

Look at stats for even AP Indy and Storm Cat. Strange but true category.

[wgc517]

That is true but people are still breeding to those older proven horses so they must feel that the ability to get that better foal is still there.

[Linda_d]

All I know is, as stallions get older, they have fewer great foals. Why? Many reasons probably.

Look at stats for even AP Indy and Storm Cat. Strange but true category.

Wouldn't fertility issues and smaller books also come into play somewhat?

It would seem unlikely that an older stallion (20+) would continue to be bred to 75-100 mares each season. Some very old stallions might only breed a handful of mares.

Also, if a stallion was having some fertility problems, he would not only produce fewer foals, but the owners of some of the best mares might go elsewhere rather than risk having their mares open for a year.

[kimberley mine]

It's not just fertility that can lead to smaller books. Physical issues might cause that as well. Think Kingmambo with his neck problem, Successful Appeal colicking a few years ago and needing the rest of the season off, or this year Lonhro getting injured and needing to stay out of the shed for a while.

[Jorge]

Secretariat is the all-time good example. He came from two old equines, yet his quality was quite unique. Go figure! Then you have Mr. Prospector, who sired his sole Ky Derby winner (Fusaichi Pagasus) when over 26. Go figure again! Then, if you don't want to cite a top-notch horses, take the case of Restless Native, who sired G-1 winner Restless Con at age 26. Restless Native managed to mate Filouette as a substitution for another younger sire. People lose faith in older sires too quickly. I would really like to examine statistics where countries with a limited supply of sires are forced to use their sires "forever" and see their stud records. Perhaps the US is not the best example because there are so many sires here to choose from that the statistic is too confusing.

[Linda_d]

I think that Jorge brings up a good point, especially these days when so many of the best mares are owned by farms/individuals breeding for sales results, and so go to the currently popular sires, many of which are fresh off the track.

It would be interesting to compare the "success" of older TB sires to the the "success" of older AQHA and Standardbred sires since these are significant "racing" breeds.

I'm not sure that it would be accurate to say that older AQHA, APHA, and ApHC performance sires produce fewer great horses than younger ones, but coming up with good criteria for measuring "success" would be a lot harder than it would be for race horses.