Old mares?
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strideaway
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Old mares?
Please enlighten me, we had company over the other night and were informed that old mares can not produce good runners.This man said there are studies out there proving this.Can this be true?We have an older mare that has producer very good runners in the past and we hope she keeps it up for at least another couple of years.Thank for any input, C.
If you have a proven producer, that is gold.
That statistic is often quoted - that a mare's best runners are usually among her first four foals.
This argument was brought up to me at a sale last year - I pointed out that the particular mare had produced 10 runners and 9 winners, a more relevant statistic, I thought. There are certainly many examples of this phenomenon.
Statistics are great for when you are sitting in the arm chair with a sales catalog trying to eliminate horses, but I'd hang on to that mare, and try to breed a good filly from her to keep.
That statistic is often quoted - that a mare's best runners are usually among her first four foals.
This argument was brought up to me at a sale last year - I pointed out that the particular mare had produced 10 runners and 9 winners, a more relevant statistic, I thought. There are certainly many examples of this phenomenon.
Statistics are great for when you are sitting in the arm chair with a sales catalog trying to eliminate horses, but I'd hang on to that mare, and try to breed a good filly from her to keep.
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StealingKat
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Statistics are bunk... If you have a good mare that is producing healthy gorgeous foals go ahead and breed her. My best mare is in her very late teens and keeps producing amazing conformationally correct babies. I often encourage people to bid on the older ladies at auction as they will produce nicely and the price range is generally better. I often open my doors to other breeders "rejects", these older mares are like gold to me and they end up with a forever home. It works for both the mare and for me 
Always bet on the grey!!
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Intrinsic Worth
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Everyone can point out the exceptions but for an over 15 year old mare to produce a stakes quality animal is extremely unlikely and the odds get more heavily stacked against you every year. The stat is something overwhelming like 80 % of all graded SWs are in the first 4 foals. It is also far more likely that you'll have complications with the pregnancies the older she gets.
Where is that statistic from? Curious...
I question how that statistic is being interpreted. If a large fraction of all graded SWs are in the first (insert small number) foals, it does not follow logically that older mares produce lower quality offspring. To say that, you would have to look at mares who have produced many offspring and see if there is a bias as to which ones are more successful.
This statistic can be easily explained by recognizing that few mares produce large numbers of offspring, so if you look at any random sample of horses, graded stakes winners or otherwise, they are more likely to be among the first n offspring of their dam (where n is a small number).
I'm not saying that the bias doesn't exist (I can think of reasons why it could be biased in either direction), but we need to be careful when we cite 'statistics.' Are they from reputable sources? Are they relevant? Are we interpreting them correctly?
We also can't rely on anecdotes to "disprove" a statistically significant trend.
I question how that statistic is being interpreted. If a large fraction of all graded SWs are in the first (insert small number) foals, it does not follow logically that older mares produce lower quality offspring. To say that, you would have to look at mares who have produced many offspring and see if there is a bias as to which ones are more successful.
This statistic can be easily explained by recognizing that few mares produce large numbers of offspring, so if you look at any random sample of horses, graded stakes winners or otherwise, they are more likely to be among the first n offspring of their dam (where n is a small number).
I'm not saying that the bias doesn't exist (I can think of reasons why it could be biased in either direction), but we need to be careful when we cite 'statistics.' Are they from reputable sources? Are they relevant? Are we interpreting them correctly?
We also can't rely on anecdotes to "disprove" a statistically significant trend.
„Age of mares“ and breeding-success is a most interesting question – statistics on this theme are often misunderstood as it is difficult to exclude the biases in them.
I’ll give You an example:
I’ve data on 1,711 contemporary (German) mares with at least 2 foals (up to 13; in total 7,461 foals) that got a handicap-rating on their performances on the race-course (here is the first bias: considered are not all offsprings but only those who had run and got a rating). Average foals by mare is (7,461 / 1,711 =) 4.4 in this sample.
The “best offspring” in order of birth and measured by handicap-rating is the “first” by 31 percent, the “second” by 30 percent and the “third” by 19 percent. But: 61 percent of the mares considered had only 4 rated foals in total. There are 153 mares with 8 and more rated foals, 80 of these mares (50+ percent) had their best foal as 4th or later. The only one mare with 13 foals in this sample had her best with the 11th.
What You can’t see in this statistics is (and this is the most important bias!): which type of mare has many foals – only those whose first foals did so well that the mare continued breeding and only so had the opportunity to get a better later on? Are breeders more patient on a mare’s (below average) breeding results in mares who had well above average racing-performances of their own?
Some years ago there was a research in fertility of tb-mares. It showed that there is a steady ( “rising”) and significant decline of fertility by age of mares. So the question is: do breeders breed their young mares with a high fertility to better stallions than later on when the chance of fertility is lower? Is a decline in class of sires used another reason for less “best” foals in aging mares?
I’ll give You an example:
I’ve data on 1,711 contemporary (German) mares with at least 2 foals (up to 13; in total 7,461 foals) that got a handicap-rating on their performances on the race-course (here is the first bias: considered are not all offsprings but only those who had run and got a rating). Average foals by mare is (7,461 / 1,711 =) 4.4 in this sample.
The “best offspring” in order of birth and measured by handicap-rating is the “first” by 31 percent, the “second” by 30 percent and the “third” by 19 percent. But: 61 percent of the mares considered had only 4 rated foals in total. There are 153 mares with 8 and more rated foals, 80 of these mares (50+ percent) had their best foal as 4th or later. The only one mare with 13 foals in this sample had her best with the 11th.
What You can’t see in this statistics is (and this is the most important bias!): which type of mare has many foals – only those whose first foals did so well that the mare continued breeding and only so had the opportunity to get a better later on? Are breeders more patient on a mare’s (below average) breeding results in mares who had well above average racing-performances of their own?
Some years ago there was a research in fertility of tb-mares. It showed that there is a steady ( “rising”) and significant decline of fertility by age of mares. So the question is: do breeders breed their young mares with a high fertility to better stallions than later on when the chance of fertility is lower? Is a decline in class of sires used another reason for less “best” foals in aging mares?
This is a case where statistics don't tell the whole story. I would think, generally speaking, older mares that have produced stakes winners at an advanced age have already produced stakes horses early in their breeding career. This would insure they are being bred to good stallions, which will increase their chances of producing stakes winners again. On the other hand, mares that haven't produced stakes horses early in their career will likely be bred, if at all, to much poorer or unproven horses the older they get. So statistically, Im sure it does show that older mares produce less stakes winners, but that statistic is largely driven by what the mares do as younger mares.
Also it is difficult to get an older mare into a highly successful stallion's book, unless she is one of those rarified mares that is a multiple stakes producer.
Also it is difficult to get an older mare into a highly successful stallion's book, unless she is one of those rarified mares that is a multiple stakes producer.
Nerd wrote:Where is that statistic from? Curious...
I believe I saw it in MarketWatch. Bloodhorse has done a few articles outside of Market Watch as well. There was a corollary statistic I recall as well which was something like if a mare hasn't produced a SW by a certain age that it is extremely unlikely that she ever will--so it was crossindexed by quality as well as quantity.
halo wrote:This is a case where statistics don't tell the whole story. I would think, generally speaking, older mares that have produced stakes winners at an advanced age have already produced stakes horses early in their breeding career. This would insure they are being bred to good stallions, which will increase their chances of producing stakes winners again. On the other hand, mares that haven't produced stakes horses early in their career will likely be bred, if at all, to much poorer or unproven horses the older they get. So statistically, Im sure it does show that older mares produce less stakes winners, but that statistic is largely driven by what the mares do as younger mares.
Also it is difficult to get an older mare into a highly successful stallion's book, unless she is one of those rarified mares that is a multiple stakes producer.
This is another case where California is an island onto itself I suspect. Pour over the various Barretts catalogues and you will see the same mares over and over, year after year, having produced nothing, probably never will produce anything, but the foal factory keeps spitting them out.
Of course if you are breeding for yourself, you can do anything you want but anyone breeding commercially should bear in mind that there are buyers out there who will put a line through any foal out of a mare more than 18 years old no matter how nice or who she's by. There's a reason why the page includes the dam's birthdate and some buyers take that piece of information very seriously.
In addition to what Halo said, which I agree with totally, another thing that should be considered is that most mares' first breeding is their best. It's the one entered into with the highest hopes, and it's often--until a mare has proved herself--the one where the most money is spent on a stud fee. Depending on the quality of the foals, mares are often bred less and less well as they age, making that statistic a self-fulfilling prophecy.