Choosing a Stallion for your Mare

Stallion selection for each mare   is the most important choice of the breeder - but we are not given much guidance on this 

The chances of breeding a top horse improve when breeders use all the tools and information at their disposal - from many different sources.  No one one method will guarantee success - or all breeders would be using it. 

 A combination of factors must be examined together in choosing stallions -  using scientific based  breeding principles  and applying an intentional selection process based on our goals - contingent upon science, history, a basic knowledge of  genetic inheritance, study of bloodlines and close relatives, genetic compatibility, balanced breeding principles,  evaluating conformation, temperament, soundness and on how these all interact with what the mare actually needs to bolster her strengths and improve weaknesses

Stallions should be chosen by focusing on what the mare needs first and foremost - and not because of his own  spectacular qualities . Specularity is unfortunately not an heritable characteristic -  compelling as it is

Selecting stallions from hyped up social media clips, or because other breeders are using them, or because of their breathtaking movement  - is a slippery and tempting  slope

It is about choosing a stallion that will raise the probability of breeding a top horse from the cross with your mare - it is the cross that is important, and not the traditional focus on the stallion

A very useful  tool that  breeders can add to their selection process is balanced breeding principles .

Choosing stallions who are genetically compatible with your mare   is the starting point for deciding whether to proceed with a stallion .  If the genetics do not  build on each other's strengths or blend together  in such a way that the power of the dna from superior ancestors may be available to the  foal - then no matter how spectacular the stallion -  it is unlikely to yield quality results

See Balanced Breeding Section

Top breeding stallions  reflect the principles of balanced breeding -  it can be seen in the  pedigree placement and reinforcement of their dominant superior ancestors - but these prepotent creatures are fairly rare - 90% of stallions fail at stud across all disciplines -  and those that fail have a much looser pedigree structure - they  are unable to reliably transmit type and sport ability in the progeny- unless they meet the right mares

Many of the stallions that fail at stud are freakishly talented riding horses, performance test winners and Bundeschampionate or World Young Horse Champions - but they are sold on as riding horses after one or two disappointing  foal crops because they do not have the tight gene groupings in their pedigree that dominant breeding stallions have - and the bigger problem is that they are largely missing out on meeting mares that carry the strains they need to produce well

Breeding strategies for selecting stallions   have traditionally focused  on conformation  or on breeding  champion parents together

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Crossing two champion parents  definately seems logical  - although history tells us the rate of success for this concept has appalling statistics  - and yet breeders of all animals  keep  on doing it 

See the Best to the Best section

Many breeders are still falling for the good looks trap and pick the best looking individuals with perfect conformation for breeding - again this seems logical - but history shows us that many of these horses have weak pedigree structures and are unable to reproduce their desirable characteristics. Conformation will not save poor genetic matches - it should be one of the final checks and not the starting point in basing breeding decisions.

See Type to Type section

A fancy pedigree full of top performing stallions has been a well tried method - but the blood of all top stallions does not always  work together well 

 Stacking the pedigree full of GP performing stallions , or Olympic winning stallions - does not translate into a foal with GP ability  

 Nor will a fancy pedigree over-ride conformation flaws in the mare

A great deal of  breeders focus on popular young stallions  , many of whom do not have foal crops on the ground yet - this  is risky , one dimensional, and generally unsuccessful - especially given that 90% of stallions fail at stud .

Young Stallions

It is very difficult to determine what a young stallion will pass on by evaluating his own conformation - and impossible to know what he will pass on in terms of athleticism and performance -  we do not know what genes are setting  his type or sport ability . Examining his  parents, grand parents, close relatives and any siblings in sport  can give clues -  If he has siblings in sport and is from a good female family  that is another good indicator of reliability

These female families should  have produced international competition horses - not just show winning mares and licensed stallions that had no career under saddle.  Some branches of certain families are more successful than others 

The actual dam of the stallion is paramount  - with no data available on the young stallions producing ability  - you are relying on the  mares  power - her temperament, conformation ,  soundness and production ability

If the dam is from a strong  female family she  may be carrying superior mitachondrial DNA and sex lilnked genes on the X chromosome  which could make all the difference to a stallions ability to produce top tier foals and horses

See section on mitachondrial DNA

As Madam Vuillier said " It is the mare that makes the stallion and not the other way around"

Stallions rely   more on their maternal strength to succeed as sires  rather than their  male line inheritance -otherwise all sons of prepotent sires would succeed at stud

 Good female  ancestry raises the probability of  reliable and superior producing power

 Once a stallion has a good number of GP progeny on the ground his    ability to transmit superior qualities can be determined in other ways

Hands down the best way to  evaluate   what  a stallion passes on is by appraising  as many of his progeny as possible - but this requires a stallion to have had at least several foal crops and better yet successful progeny in sport  - not simply assessing his progeny from foal shows, mare show performances ,  and newly licensed stallions with no career in sport

This means a stallion would need to be 12 years old to evaluate any possible GP progeny

We need  to watch the progeny  in sport to determine the athletic ability and contribution  from the  stallion

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Balanced breeding prinicples and pedigree analysis are the ideal starting point in narrowing down a list of stallions for each mare - in line with breeding goals

They  are the most reliable way to ascertain     the genetic dominance of  the mare in question ,-  then a short list of  genetically compatible stallions can be drawn up 

This way you do not end up getting crazy and impulsive  about a stallion and then have to work backwards to get a  mare to fit

Stallion pedigrees can be evaluated in the same way and hypothetical test matings can be run between stallion and mare - to find a genetically compatible mating where the parents lineages are a tapestry of interwoven bloodlines -  and are present in such a way that the foal has the best chance of inheriting the superior DNA and sport ability of its superior  ancestors

Clive Harper "these methods are not a silver bullet, merely a way of minimising the risks of breeding failure"

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Pedgiree - expert Clive Harper makes the most profound statement  on selecting stallions 

" The most important principle in breeding - which most people find difficult to understand - is that a stallion will tend to get his best progeny from mares whose pedigree lines complement or supplement his own genetic strengths"

To complement means the mare may add an element - such as providing a daughter of a sire to balance a son of that sire in the stallions pedigree, or adding a full sibling to an important line in the sire's pedigree. To supplement means to add more lines of what is already present in the stallion pedigree -   to strengthen and cement the effect of important bloodlines and ancestors.

Examining a stallions top progeny in sport and his stallion sons is definately the most effective way to determine what patterns are working with  his own pedigree structure

Graf Top Pedigree  

A simple but effective  example is  stallion  Graf Top

Graf Top is by Graf Grannus - who is 3 x 4 x 4 to elite  sire Gotthard - this is his pedigree dominance within 7 generations

He also has Goldficsh ii at   6 x 6 x 5 x 6 x 4    - he is the sire of Gotthard and appears once as sire of Graf also

This line is present only via sons (which will ideally  require a correction  later)

Graf Top's dam  Capries  comes to the genetic party by  adding  in another  daughter line of Gotthard in the  3rd generation 

Graf Grannus has the stronger genetic pattern here and she is able to tap into and expand that by adding another line of what is already present -  Gotthard is represented here at  4 x 5 x 5  x 3  - right in the engine room of the pedigree

   It can just be this simple -  adding in one line of what is already dominant in the stallion

Foals by Graf Top have a raised probability of  inheriting the superior sport characteristics of Gotthard with these duplications in this position.

It gives an example of how a mare  who does not have a  solid genetic dominance of her own  - can be used in breeding - to breed a top horse. 

Capries is the product of an outcross mating.  She is by Calypso II out of a Gotthard / Steinpilz (TB) mare - holstein / hanoverian / thoroughbred.

She has no common bloodlines both sides of her pedigree at 7 generations - and at first glance is not a good candidate for breeding -  unless  - with a closer look -she has superior ancestors and  elements in her pedigree that can be built on- with the right stallion.

Capries actually produced a full brother - Graf Top II who on record at Horse Telex only had 13 progeny - yet he produced 4 PSG dressage horses and one 1.40 m showjumper - so something in the crosses was clearly working

We will look at the  show jumper   that  Capries produced as an example  of how to build on her genetics and how to choose a stallion for her  - Stakkato's HIghlight - by Stakkato.

Stakkato is an excellent choice for Capries and is a direct example of what Clive Harper is talking about when he says that stallions tend to get their best progeny from mares that supplement and complement their own genetic structure (and vice versa).

Stakkato HIghlights pedigree

Stakkatos sire Spartan is out of  Gottilde - who is in fact a  full sister to Capries'  own dam  - Geri.

These full sisters appear at 3 x 2 in an inbred pattern - Gottilde and Geri - and Geri is very importantly on the tail female line of this horse, which takes advantage of any superior mt DNA and sex linked genes from this family which has produced some elite performance horses

These full sisters are not just any horses - both are by Gotthard who is the linebred target in this instance

Geri also produced  the GP dressage horse Giovanni (Graphit) , and her daughter Candy produced well known stallion Laptop (Loredo)

Full sister Gottilde is dam of sire Spartan (Servus) and dam of a 1.60 m and  1.50 m show jumpers Alwins As and Starlett N

Geri and Gottilde are also  sisters to Gambrinus  1.60 m show jumper

So not only does Stakkato add a full sister to a horse in Capries' pedigree - he also adds  2 crosses of Gotthard - in a similar way to Graf Grannus -  allowing Capries to link in with her one line of Gotthard -  to the sires greater genetic strength here.

And very importantly Stakkato adds a Goldfisch II  daughter on the 5th generation - this is a line that is usually only seen via sons only  so a daughter is very valuable here - as we have 3 crosses of Gotthard who is by Goldfisch ii - so  there is an over riding male dominance in this line with 3 sons - but the daughter on the 5th  brings it into a sex balance which is more effective for  the transmission of sport ability  to the progeny.

Stakkato in effect brings potency, reinforcement and balance to Capries' own pedigree structure.

This closely  related group of  mares were bred often to Stakkato or his son Stolzenberg -  so the breeder obviously realised that something about Stakkato was working with his mare line - even if he didn't know  exactly why

The mare Capries happened to get what she needed in this mating, and also in the mating with Graf Grannus to produce the stallion Graf Top - but these things happen rarely by chance. A different stallion with no common bloodlines would have left a random outcrossed pedigree with no common relatives either side - a foal with no genetic potency - that may have been a nice riding horse but would have been little use in sport  or for breeding in the next generation

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This is a very good example of how pedigree analysis  can show you  how matings can be planned for in a concrete way  -  how  to build in and reinforce particular superior ancestors in the mares pedigree and bring in female family bloodlines which you would not get in random matings to popular stallions

It is an excellent example of how running test matings between  mare and stallion pedigrees,  can effectively be used to manipulate the genes that will be available to the foal - and to allow the breeder to have more control and creativity in the selection process - instead of just blowing in the wind with haphazard choices

By running test matings  breeders will end up considering stallions they may never have looked at in a million years  instead of going with what is popular - it can mean bringing in different and perhaps fresh bloodlines or revitalsing female families that have lasped into obscurity for a few generations

 This is also the beginning of putting the mares needs first - and this is why balanced breeding and genetic compatibility should be the first stop in stallion selection

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The basic key to determining a stallions, or any horses genetic strength, is to take note of which horses are duplicated in his pedigree - this is a start. Also take note of which generation they are in, and whether these lines are coming in via sons only, or sons and daughters, (sex balanced line breeding )  or daughters only. (Filly and colt factors )  This way you can see which corrections need to be made in the next mating. 

See links to Balanced Breeding and Analysing Pedigrees.

This is how breeders can make more informed decisions in choosing stallions, and begin to think in generations - see how the mating the following year can be used to cement the bloodlines you are looking to build in for the current mating

All matings require something different - the methods that have traditionally been available to breeders are inbreeding, linebreeding or outcrossing

A mare may need a stallion that duplicates certain ancestors in her pedigree  to  produce increased uniformity in  a certain type  and ability - see above example with mare Capries

Or a mare  may already have a very inbred pedigree and  require a stallion who can provide an outcross mating 

She may even require some very carefully evaluated inbreeding or heavy linebreeding

The only way to critically evaluate  which method is required is with   balanced breeding and genetic compatibility principles

Learning how to read pedigrees is difficult - but some of the basic principles can be learned with some effort. It  does take some years to develop the skills to  analyse  the  more complex and successful patterns which work and what doesn’t work - but breeding is not meant to be easy -  it is a lot of work. Similarly with riding - it takes 10 years to learn to ride a horse -  but most breeders are not prepared to give this same time frame to learn the principles of breeding.

Even if you learn  only the basic principles such as sex balancing a dominant bloodline in the stallion - as seen above in the dam  Graf Top - you will be streets ahead in the quest to upgrade the ability and type  in your  foals

Patterns of Success in Pedigrees

By far the most important way to evaluate what a stallion needs in his mares is to 

examine the pedigrees of his  stallion's top progeny and try to identify how the dam lines have connected with the stallions - by noticing any particular dam sires, duplicated bloodlines or other close relatives. 

Are there any bloodlines which keep appearing in the crosses that are too frequent to ignore? - there will be - more studies on this later

If a common factor can be recognised then we can plan our matings to copy the same pattern, and if we see this a few times in a stallion's top progeny then we can assume the bloodlines complement each other and may increase the odds of breeding a top horse. This is how nicks and genetic affinities  come into being and produce horses that are superior to both parents.

When starting out -  the simplest way of doing this is by studying the dam sires of the top progeny 

 With the top progeny of De Niro, you may notice that a considerable number of the mares are by the stallion Weltmeyer. 

Some examples are Danone 1 and 11, Desperados, Beldonwelt,  Dante Weltino, George Clooney., Delgado, Dixieland, Dreamy, Super Nova, Donatello, Dante,  Dewindo, Delmar.

Rubinstein is another common damsire for GP horses by De Niro. 

Examples are Degas, De Niro Gold, Delatio, Dionysos, Deep Impact, Voice, De Beers Degas. Diokletian, duchess, Dressed to Thrill, Delwhinnie,  Newton Domino, Denzello, Denksport, Mid West Casino, Doctor Rossi, Just Wimphof,  Kurioso , Vital Nova. 

Shogun xx is another  common dam sire of De Niros GP progeny, either as the actual dam sire or via Wanderbursch . Examples are Dagostino, Dablino, D-online, Daintree.

These are just a very small sample and it is a very simplistic model -  but these dam sires occur frequently enough for it to be a pattern. Do the research  to see what is actually working, then you can look at the pedigrees to see why.

If you have a mare with any of these dam sires or their sons,  or appearing  as grand dam sire,  and you want to breed with De Niro - then you would be following a successful pattern.

It is far better of course to evaluate the entire pedigree of the mare with the stallion to get a true picture of what is working - the actual power line in the mating could be in the bottom quadrant  of the  mare line - but it is better than a  total shot in the dark

Pedigree analysis is the first tool  to come up with a shortlist of stallions that are genetically compatible for your mare - before you then go on to factor in the other equally important aspects of conformation, athleticism, temperament and soundness.

It allows you to draw a line through stallions that, although they have great commercial and popular appeal - are not going to add to the mares genetic strengths and may even detract from them. 

All  foals will tend toward the mean average of the breed  in terms of quality - and not toward the superior aspects  and qualities of  their champion  parents.   You may well get a far more outstanding foal from a stallion who is less breath taking himself,  and not as well known as say  Glamourdale or Viva Gold - but quality and athleticism are the goal in breeding sport horses rather than an average foal from a 'name' father  -  and  overall quality is what will attract the buyers and  sell the foal

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If you have a new mare and you know nothing about her breeding history or you bought her as a foal and do not own any other members of her family - then you won't have any clue as to how she will produce. Picking an older proven stallion for mares like this can be a good idea, because you can evaluate many of his  progeny  in terms of type and conformation and also learn what bloodlines work with these stallions.

For older mares who have progeny to evaluate,  or even better if you bred the mare yourself and her grand dam, you will have a far better idea on how that line produces.

The right choice for the mare is a stallion that  raises the probability of producing  a high calibre vital, athletic typey foal -  not just using a stallion because it competed at the Olympics, or because everyone else is rushing to use that stallion , or because it is unimaginably spectacular and haunts your dreams.  Aside from the lucky nick mating where the stallion just happens to ' nick' with the mare -  average foals will be the result if the stallion choice is not based on extensive research and putting the mares needs first.

Picking Young Stallions

it is  very difficult to determine what a young stallion will pass on in terms of his own conformation and impossible to know whether he will transmit his own  superior athleticism and movement qualities.

Young stallions are invariably  chosen for their incredible movement but they have no foal crops to evaluate and there is no way to know if they have the ability for top level sport

To raise  probability and  reliability factors young stallions should be from good female families which have produced international competition horses at top level sport  - and not just show winning mares and licensed stallions with no career in the sport. 

The stallion's actual dam is paramount. With no data on the young stallions producing power  you are relying on the mares production record , her soundness conformation, and her temperament to determine her heavy lifting power

If she is from a strong female family line she may be carrying superior mtDNA or sex linked genes which could make all the difference to the stallions ability to produce top tier foals

"It is the mare that makes the stallion and not the other way around" Madame Vuiller

Maternal strength is what enables a stallion to succeed at stud and not his male line inheritance -if the opposite were true then all the sons of prepotent sires would be a success at stud

In young stallions, good female ancestry is the best determinant of long term success - it raises the probability of reliable and superior producing power

If a very young stallion has siblings and close relatives that are successful in sport, this also helps to raise the reliability  factor

Once a stallion has produced  several GP progeny his ability to transmit superior type and sport characteristics can be evaluated in other ways

Top producing and rare prepotent stallions will usually have a high concentration of close relatives in their pedigrees - often they will have a full brother and sister feature within 6 generations, or a pair of full sisters, or a complex pattern of three-quarter related siblings. Overall, they will have more complex inbred pedigrees rather than being the result of an outcross mating

If these same tight groupings of  close relatives  and patterns from superior ancestors  can be seen in the pedigree,  it is a  more reliable way of choosing young stallions  - because it is a fairly safe bet they will be good producers.

Picking young stallions - while sometimes taking advantage of the latest genetics -  is always going to be  riskier.  The stallion may be retired to stud without a ridden career and you will not know if he had the ability to compete up the levels and to stay sound and sane for this process.

I picked the young stallions Destano, Dante Weltino, For Romance, Quaterhit, Franklin and Morricone in their first year of breeding  at 3 years old because they had very inbred pedigrees within 6 generations and I knew they would carry a certain amount of prepotency for passing on their top qualities. You can see the trends in these pedigrees on the Analysing Pedigrees page. 

i was either using them as outcross stallions or 

I  had mares that would tie into the inbreeding of these stallions - as Clive Harper says above - a stallion will tend to get his best progeny from mares who supplement and complement his own genetic strength.

Interestingly, all these stallions ended up at Grand Prix level and two at the Olympic games - i had no way of knowing this would happen when i bought the semen -  they went all the way - they had the pedigree structure to access the power of their bloodlines and they were in the right environment to succeed in sport 

This highlights the problem of most horses not having the correct opportunities to go all the way to the top. These stallions - even though they had the ideal pedigrees to be top producers and performers - got lucky - they were born in the right environment at the right time and brought on by top riders who could bring out and nurture the power of the bloodlines these stallions clearly had inherited - it shows how equally  important environment is in genetic expression

By the way my next inbred stallion prediction  is Dream Royal  and he is from a top mare family - his  semen should be available next season in Australia - this is one stallion i would be excited to buy semen from as a youngster and eagerly await his progeny record 

So, picking a young stallion because he has an inbred pedigree or because you are after a specific factor to build into your mare's bloodlines is one reason to do so. Picking a young stallion purely on the basis of mind blowing movement is random lottery style breeding and very unlikely to produce a good result - unless there is a lucky nick with the mares pedigree.  It is putting the stallion first with no regard to the mare's requirements.

Breeding is about weighing risks and testing limits.  And it is important that a certain percentage of breeders take  risks for the future of the breed and to create great breeding stock

Looking at Stallion Type

Stallions will generally be of a good type – they have had to jump through a lot of hoops to get approved as breeding stallions – their general conformation and movement will be good if not outstanding. 

Stallions have to go through a stallion test with regard to type, performance, aptitude for dressage and jumping, and temperament. These testing periods are getting shorter and shorter-  -  this used to be a 100 day test for many years , then a  30 day test and is now mostly a 2 day test. Not only that -  stallions can now  obtain a provisional license just from their performance on the lunge rein.

Many stallions will appear outstanding in their phenotype – but all will be of a certain standard. They will of course have differences in the angles of their long bones, cannon bones, pasterns, shoulder angle, length of neck and neck set but overall they will pass muster.

It is very difficult , if not impossible to know what new, young stallions are going to breed on in terms of type. Most  spectacular young stallions will have one  or two foal crops and then disappear from view, having been unable to reproduce their own types and abilities in the progeny - over half of performance test winners disappear in this way.

If pedigree compatibility was evaluated as  one factor at the stallion licensing days, - this would enable those stallions that do not have breeding pedigrees to be sold on as riding horses and would also allow those stallions that may not be as spectacular - but have pedigrees with tighter gene groupings, to be given a chance at breeding

This would  change the landscape of evaluating stallions and could drastically improve the  90% failure statistic

We are not there yet -  hopefully one day we will be - in the quest to breed better horses

Evaluating Progeny

The very best way to determine  what a stallion will pass on in terms of type is by evaluating as many of his progeny as possible. In Australia this may mean watching as many foal auctions, foal show days, and online video clips as possible - and taking trips to Germany.  Outlier countries like Australia are at a serious disadvantage as is stated by Tom Reed at Morningside stud - we do not have the 'soft knowledge' that european breeders have through observing generations of bloodlines in the flesh

Look at what a stallion  throws in terms of neck set, loin and croup angles, point of shoulder,  shoulder angle, angle of the humerus from  point of shoulder to elbow, length of femur and ilium in the hind end,  hock angle, stifle height and legs.  

It is far easier to evaluate a stallions progeny for type when they are 3 years and over. These things are very difficult to see in foals where the bones have not reached their mature length – if a foal will develop into a horse with a very weak long croup , a bad sacro iliac position, or a very over angled hock, it is impossible to see these at this young age.

 It is entirely possible that a stunning foal will be a very average 3 yo and vice versa.

Notice if a stallion stamps his foals in anyway – if there is a lot of variation in the foals then the mothers must have the stronger genetic pattern  and override the type of the foal.   If the foals all have a similar look it can indicate a level of prepotency. Study the stallion's parents,  and  all 8 grandparents, and  as many horses in the pedigree as you can up to 6 generations.  If the stallion is linebred to certain ancestors, then take a look at these target ancestors  because they could well be the main influencer of type and ability  in the foal.  Study any full or half siblings of the stallion to determine the eventual type of your foal

If the stallion throws similar features  in the foals over a wide variety of mares then he may be prepotent for some of these characteristics. If you see his progeny have the same shoulder angle or hip angles over 3 generations then it may be a heritable set of characteristics. 

Stallion Rankings

The WBFSH puts out the top sire list  each year for dressage, showjumping and eventing stallions. These should be considered along with  lists for the top 100 dressage / jump horses, and the list for the top 500 dressage horse world rankings.

However,  although they make interesting reading, stallion rankings are in many ways not reliable enough to base breeding decisions on. The only way these rankings could be made useful is to include how many foals each stallion has sired - in total and yearly - and therefore how many chances did each stallion have for a chance of producing an international dressage horse or 1.60  m jumper. A sire with 3000 foals born has a far greater chance to produce international sport horses than a stallion with only 700 progeny - this unfairly skews the rankings.

Often one of these 'top' ranked sires will have only one or two competitors that scored all the points.

A current example of this is the stallion Zonik - who was ranked 55th two years ago but who is now ranked number 10 with a bullet in the list of 2025 top sires - and this is largely due to the success of his GP son - Zonik Plus.

This is also an example of how - from a few short videos on the internet - this stallion rocketed  to superstar popularity with breeders rushing to buy his semen.   At least he is a successful GP competitor and not just a young freakish mover.

A long career at the top of the sport indicates that the stallion can tolerate the years of education and the tough rigors of training, which bodes well for soundness and temperament -   which are heritable characteristics.

Another example would be Valegro and Negro - how Valegro single handedly shot his sire into the stratosphere.  Negro of course does have other GP competitors but many breeders would have run to use him based on his best son - and what a son.

Research by Chris Hector  revealed that in 2009, 23 out of the top 30 dressage stallions had only 1 or no progeny on the world's top 100 dressage horses.

Unless breeders are enthusiastic about research and performing due diligence before choosing stallions, it is very easy to get the wrong impression about all the stallions on the top 30 list.

The stallion rankings should also provide information as to which of these stallions appeared as dam sire of top international horses. Sometimes a stallion can be far more influential via his daughters than his sons, examples are Weltmeyer,  Rubinstein , Brentano ii 

So the rankings, while interesting and somewhat useful, are not much help in choosing a stallion for each individual mare based on her own traits, strengths and weaknesses and pedigree.

Just because a stallion like De Niro  or any stallion on the WBFSH rankings - has 105  GP progeny this does not mean he is a correct choice for each mare

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These rankings are not much help unless we know exactly how many progeny a stallion has, but we can assume for most of the top stallions, they have thousands - this would indicate a failure rate of at least 90 %(if the goal is to produce a Grand Prix horse). Perhaps the success rates are higher for some jump stallions

There are far more unsuccessful progeny produced by any stallion than the small number of GP ones. If a stallion like De Niro,  has world wide produced around 8000 foals   then the 105 GP progeny figure takes on a different significance and the failure rate is more glaring

What is the difference with the top progeny and the ones that don't make it? Obviously, some of these will have died, gone unsound, or been sold into unsuitable riding homes or kept for breeding. Assuming that many of the progeny had a fair go in the competition ring with the correct environment and rider -  the difference   must be the mare - and how her pedigree crosses and blends with the stallions - the stallion is the constant factor - only the mares change.

Having analysed the pedigrees of all 105 of De Niro's top progeny, this figure of successful  offspring could be raised much higher if balanced breeding principles were used to construct matings - many of his successful progeny had patterns that repeated throughout the different pedigrees way too many times to be a happy accident, and certain dam sires and grand dam sires were repeated in the same manner

The best results will come from an wholistic approach - assessing genetic compatibility, bloodlines and close relatives, conformation, temperament, soundness and  keeping in mind  the health of the breed in general.