New study on age of parents...

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   A very interesting paper released today on the influence of age on racetrack outcomes...
Firstly, I did my own study on this back in 2013, looking specifically at paternal/sire outcomes as a stallion aged and the data showed that as the stallion got older, he was less likely to produce superior runners. We wrote about it in @InterThorough here - shorturl.at/AFN47 

There was some further work in July this year where in a population of Japanese horses they studied the influence of broodmare aging on its offspring’s racing performance. They found the quality of sires was significantly associated with the offspring’s racing performance rather than the broodmare’s age itself. eg. as the mare aged, she was sent to lesser performed stallions, on average, and this was a determinant of racetrack outcomes for older mares. The paper used an Average Earnings Index to estimate sire performance (a faulty metric I think) but they concluded that it was the effect of the sire that had more influence than the age of the mare - https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0271535#pone.0271535.ref013 

This paper was quite a different finding to that of Barron (1995) where she found that the average Timeform Rating of any foal out of a mare, peaks when its mother is 9 years old, after which it declines - https://beva.onlinelibrary.wiley.com/doi/10.1111/j.2042-3306.1995.tb03036.x  Similar to Barron's study, and contrary to the recent Japanese study, negative relationships between maternal age and the likelihood of winning stakes races (the highest class of races) had been reported by Finocchio (1985) - https://agris.fao.org/agris-search/search.do?recordID=US8738514 Additionally there was a Thesis done by Xiurui Cui under Dr Jill Stowe @UKAgriculture back in 2016. It was more about the hedonic price modeling of the age of the mare but had a similar finding - a negative correlation between dam age and performance - found here shorturl.at/avwy5

And finally we get to the paper released today by Sharman et al. Here is a link to the paper but I will also summarise some interesting findings in the paper below - https://royalsocietypublishing.org/doi/full/10.1098/rsos.220691

Firstly it was a large study - 41,107 dams and 2,887 sires with over 900,000 race performances by over 100,000 individual horses on British racecourses between 1996 and 2019. It is easily the largest study to look at the influence of age on outcomes....

Secondly, the study accounted for many of the factors that one would consider confounding, including the distance and going of the track that the offspring ran on as well as the number of runners in the race...

They found a ‘significant effect’ of maternal age on speed, with each additional year of age at conception decreasing the offspring speed by 0.017 yards per second which converts into a difference of approx 1sec/6 lengths over a race of one mile between, a 5YO and a 15YO dam....

Intriguingly, the paternal age also showed a decrease of 0.011 yards per second for every increasing year in stallion age – interesting given thoroughbred stallions play no active involvement in parental care. Overall the study points to ageing parents having a detrimental effect

Finally they suggest that epigenetic mechanisms might be at play, raising the question of whether parental age effects found in the study could cascade across further generations (e.g. you buy a mare who has old parents and her foals have a lesser chance of being a runner)

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brogers Members Profile Send Private Message Find Members Posts Add to Buddy List Champion Joined: 20 Feb 2007 Location: Lexington, KY Status: Offline Points: 1106	Post Options Post Reply Quote brogers Report Post Thanks(1) Quote Reply Topic: New study on age of parents... Posted: 06 Oct 2022 at 11:19am
	A very interesting paper released today on the influence of age on racetrack outcomes... Firstly, I did my own study on this back in 2013, looking specifically at paternal/sire outcomes as a stallion aged and the data showed that as the stallion got older, he was less likely to produce superior runners. We wrote about it in @InterThorough here - shorturl.at/AFN47 There was some further work in July this year where in a population of Japanese horses they studied the influence of broodmare aging on its offspring’s racing performance. They found the quality of sires was significantly associated with the offspring’s racing performance rather than the broodmare’s age itself. eg. as the mare aged, she was sent to lesser performed stallions, on average, and this was a determinant of racetrack outcomes for older mares. The paper used an Average Earnings Index to estimate sire performance (a faulty metric I think) but they concluded that it was the effect of the sire that had more influence than the age of the mare - https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0271535#pone.0271535.ref013 This paper was quite a different finding to that of Barron (1995) where she found that the average Timeform Rating of any foal out of a mare, peaks when its mother is 9 years old, after which it declines - https://beva.onlinelibrary.wiley.com/doi/10.1111/j.2042-3306.1995.tb03036.x Similar to Barron's study, and contrary to the recent Japanese study, negative relationships between maternal age and the likelihood of winning stakes races (the highest class of races) had been reported by Finocchio (1985) - https://agris.fao.org/agris-search/search.do?recordID=US8738514 Additionally there was a Thesis done by Xiurui Cui under Dr Jill Stowe @UKAgriculture back in 2016. It was more about the hedonic price modeling of the age of the mare but had a similar finding - a negative correlation between dam age and performance - found here shorturl.at/avwy5 And finally we get to the paper released today by Sharman et al. Here is a link to the paper but I will also summarise some interesting findings in the paper below - https://royalsocietypublishing.org/doi/full/10.1098/rsos.220691 Firstly it was a large study - 41,107 dams and 2,887 sires with over 900,000 race performances by over 100,000 individual horses on British racecourses between 1996 and 2019. It is easily the largest study to look at the influence of age on outcomes.... Secondly, the study accounted for many of the factors that one would consider confounding, including the distance and going of the track that the offspring ran on as well as the number of runners in the race... They found a ‘significant effect’ of maternal age on speed, with each additional year of age at conception decreasing the offspring speed by 0.017 yards per second which converts into a difference of approx 1sec/6 lengths over a race of one mile between, a 5YO and a 15YO dam.... Intriguingly, the paternal age also showed a decrease of 0.011 yards per second for every increasing year in stallion age – interesting given thoroughbred stallions play no active involvement in parental care. Overall the study points to ageing parents having a detrimental effect Finally they suggest that epigenetic mechanisms might be at play, raising the question of whether parental age effects found in the study could cascade across further generations (e.g. you buy a mare who has old parents and her foals have a lesser chance of being a runner)
	Abel Tasman...Keen Ice...Divisidero....Verrazano...Catchy...Carrick...Ivictory...

Gay3 Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 19 Feb 2007 Location: Miners Rest Status: Online Points: 55609	Post Options Post Reply Quote Gay3 Report Post Thanks(0) Quote Reply Posted: 06 Oct 2022 at 12:17pm
	Very interesting Brian, plenty of food for thought despite parental age already being factored in by many astute breeders. There are simply so many variables involved in the quest fro a horse that'll pay it's way, not to mention an elite performer
	It takes a wise man a lifetime to grow a tree and a fool five minutes to kill one.

Progold Members Profile Send Private Message Find Members Posts Add to Buddy List Champion Joined: 20 Feb 2007 Location: Australia Status: Offline Points: 3223	Post Options Post Reply Quote Progold Report Post Thanks(1) Quote Reply Posted: 07 Oct 2022 at 2:36pm
	I did a study some years ago regarding age of stallions that I am pretty sure I put in the old Breeders Guide of the Sportsman when they used to have one. The outcome was that rather than age, the number of mares that a stallion had covered was a more accurate reflection of a decrease in the number of stakes winners that they sired. Whether that holds up with the huge numbers that shuttle stallions cover now is another thing.

djebel Members Profile Send Private Message Find Members Posts Add to Buddy List Premium Joined: 07 Mar 2007 Status: Offline Points: 56200	Post Options Post Reply Quote djebel Report Post Thanks(1) Quote Reply Posted: 07 Oct 2022 at 2:44pm
	When doing a study of such vastness was it or is it possible to see at what stage of the stallions work load a top class foal was conceived ? ie, was the successful foal a early covering, a late covering, the 3rd of the day or the 1st ?
	reductio ad absurdum

Second Chance Members Profile Send Private Message Find Members Posts Add to Buddy List Champion Joined: 02 Dec 2007 Status: Offline Points: 56833	Post Options Post Reply Quote Second Chance Report Post Thanks(0) Quote Reply Posted: 08 Oct 2022 at 6:02pm
	The great and now deceased stallion More Than Ready. Just four stakes-winners winners (by my possibly shoddy research) from his current 3,4,5 and 6yo's in Oz. 1.15% stake winners to foals. Ok am being simplistic, but age shall indeed weary them on occasion.

diomed Members Profile Send Private Message Find Members Posts Add to Buddy List Champion Joined: 16 Nov 2016 Location: Roscrea Status: Offline Points: 904	Post Options Post Reply Quote diomed Report Post Thanks(0) Quote Reply Posted: 09 Oct 2022 at 5:20am
	If a mare is bred fifteen years in a row it will not be to the same stallion. She will meet stallions born on average later and later. By later I mean not older, but with a later year of birth. For example, is the mare was born in 2000, and had her first foal in 2004, and a foal every year after that with her last foal in 2020, she will have been bred to a stallion born in 2000 (same year as the mare), then to a stallion born in 2001, then in 2002, then a stallion born in 2003 and so on. Please realise that I am not saying her first stallion mate was actually born in 2000 but that that is probably the average year of birth of all the stallions available to her (actually it is probably earlier than that by a few years), and the average year of birth of her stallion mates is a later year of birth each time she is mated. You might think this minor point is hair splitting, but over the last few weeks I analysed 620,000 ten generation pedigrees and find that from 1900 to 2019 there have been interesting declines, possibly declines in quality. I tested the pedigree extracts against 159,000 ratings and there was a relationship between the numbers. The first decline was from 1900 to about 1927, the second from about 1980 to 2019 and this second decline has been a decline every year with one exception (two consecutive years gave the same figure). My guess is the first decline coincided with an excess of St Simon (1991) (m) in pedigrees, the second decline with the excess of Northern Dancer in pedigrees that began with the importation of many sons of Northern Dancer into Europe to use as sires. Breaking the accepted stallion book of 40 mares with the breeding of 97 mares to Be My Guest (1974) (m), the move to stallion books of 150/200, and the introduction of stallion shuttling increased the excessive presence of Northern Dancer in pedigrees. The numbers, graphed year by year from 1900 to 2019, clearly show the two declines. My guess is the mare's pedigree remained the same but she met stallions year by year who had pedigrees that were deteriorating (on average). I am not going to give my pedigrees calculations on here, and a second version (work in progress) might give improved results.
	foalmare.com - my thoughts about pedigree

Take2 Members Profile Send Private Message Find Members Posts Add to Buddy List Champion Joined: 04 Mar 2007 Location: Australia Status: Offline Points: 7060	Post Options Post Reply Quote Take2 Report Post Thanks(0) Quote Reply Posted: 30 Dec 2022 at 6:59pm
	Peter pring adequately covered age and crops of stallions, age of brooodies, and foaling number, in a more simplistic method than the studies referred to in this thread from memory 2nd to 6th foals cant remember crop numbers for stallions, but i think optimum ages via him were 4-12 for mares and similar for sires, have to get it out again and check on it Edited by Take2 - 30 Dec 2022 at 7:01pm
	change is simply a destination on a journey reached by taking the first step (i said that) lol www.3rdmillenniumbloodstock.com.au

furious Members Profile Send Private Message Find Members Posts Add to Buddy List Champion Joined: 19 Feb 2007 Status: Offline Points: 30978	Post Options Post Reply Quote furious Report Post Thanks(0) Quote Reply Posted: 30 Dec 2022 at 7:03pm
	Oceana and Star Kingdom had a champion, a second champion, a good, a few winners and downhill from there ect. But is it the age or just the right combination or genes.