AUSTRALIAN STUD BOOK The Australian Stud Book is the authority to which breeders must register all their bloodstock in order for the progeny to be eligible to race.

BLUE HEN A broodmare who is shown to be the ancestress of a high number of stakes performers.

BROODMARE SIRE Also known as the damsire – the sire of the dam of a horse, or maternal grandsire.

BY  A horse is ‘by’ a certain sire – this term is never used for the dam.

CATALOGUE-STYLE PEDIGREE  A pedigree set out as in a sales catalogue – usually with a tabulated pedigree at the top, a description of the sire’s achievements at stud, and then detailed information on the dam and her race record, other progeny etc. The second and third dams (and depending on room, sometimes more if there isn’t much to say about the family!) are also detailed.

COLT  A male under the age of four years which has not been gelded.

CROSS  Usually refers to a particular cross of sire over broodmare sire.  For instance, Nothin’ Leica Dane and Brackenbury are both bred on a Danehill (sire) / Sir Tristram (broodmare sire) cross.

DAM    Mother of a horse.

DAMSIRE  Also known as the broodmare sire – the sire of the dam of a horse, or maternal grandsire.

DISTAFF  The female or dam’s side of the pedigree.

ENTIRE Male horse over three years old which has not been castrated, also known as a stallion.

FAMILY NUMBER  Family numbers were developed by the Australian Bruce Lowe earlier this last century.  Family number 1 had produced the highest number of English Classic race winners, while Family 42 had produced the least.  While the system has been found to be severely defective (for instance, he did not consider horses racing the U.S.A.), the family number system is useful to line breeders, who use the family number to help identify horses tracing to the same taproot mares.  Family numbers are passed on through the tail female line – a stallion cannot pass his family number on to his progeny.

FILLY A female under the age of four years.

FIRST DAM  The dam or mother of a horse.

FIVE EIGHTHS SISTER / BROTHER Where five of the eight great-grandparents are the same as those of another horse. One of those common grandparents must be on the tail female line. See Tail female line.

FOAL  The offspring of  a dam.  The foaling season for southern hemisphere Thoroughbreds officially commences on 1st August each year.  Foals born on or after that date officially turn one year old (yearlings) on the following 1st August. Northern Hemisphere foals start their year on 1st January.

FROM  A horse is ‘from’ or ‘out of’ a certain dam – these terms are never used for the sire.

FULL SISTER / BROTHER A horse by the same sire and same dam.

FULL SISTER / BROTHER IN-BLOOD A horse whose four grandparents are exactly the same as another horse – even though one or both of the actual parents are not the same, but are full sister or brother to the parent/s of the other horse.

GELDING  A male horse which has been castrated.  Gelding is usually performed in a horse’s second or third year, but it can be carried out from a very early age.   Reasons for gelding include unruly behaviour, lack of concentration on raceday activities and excess body weight (stallions generally carry more body fat than geldings or mares and consequently place more pressure on their legs). Geldings can be turned out with other horses, while stallions generally cannot.

HALF SISTER / BROTHER  A horse from the same dam.  A horse by the same sire is not termed a ‘relation’ – it is referred to only as being ‘by the same sire’.  This is because a stallion may have 100-odd progeny every year for many years, whereas most mares will only have 10 or so foals in their lifetime, making the relationship more relevant.

INBREEDING Mating a mare to a stallion who carries the same individual within the first four generations is ‘inbreeding’ to that individual.  For example, Danehill is inbred to Natalma, who appears on the second remove of his sire and the second remove of his dam.  As a product of that mating, Danehill is said to be inbred 3 x 3 to Natalma.  To give even more detail to this description, Danehill is inbred 3m x 3f  – ie, through a son (m) and a daughter (f).  This method of description was developed by David Bay and is now widely used.  See ‘Sex balanced’.

LINE BREEDING  Takes over as an extension of inbreeding – the reinforcement of ancestors further back in the pedigree. If a horse is described as being linebred to Star Kingdom 4m, 5f x 4m, that describes that one the sire side of the pedigree (sire and dam separated by the ‘x’), that Star Kingdom appears through a son (‘m’ for male) on the fourth remove and a daughter (‘f’ for female)on the third remove further down in his pedigree.  The dam carries a son (m) of Star Kingdom on her fourth remove, or generation.

NICKS  / CLICKS  Crosses (usually of a sire over a broodmare sire) which have proven to have an above average record for producing stakes winners.

OUT OF  A horse is ‘from’ or ‘out of’ a certain dam – these terms are never used for the sire.  It would  be physically impossible for a foal to be ‘out of’ a stallion!

OUTCROSSING  No exact definition in horse breeding has been agreed upon for outcrossing, however it is the mating of a mare to a stallion who has no significant ancestors common to her pedigree within the first few generations.

PEDIGREE  Family tree of a horse – in the Thoroughbred it can be traced back to the creation of the breed (from a mixture of Arab and Barb horses) two hundred years ago. Modern day Thoroughbreds can trace their ancestry back to one of three particular foundation stallions, the Godolphin Arabian, the Byerley Turk and the Darley Arabian.  The Australian Stud Book is the authority to which breeders must register all their bloodstock in order for the progeny to be eligible to race.

PINHOOKING  The purchase of a weanling with the intention to re-sell it as a yearling, or the purchase of a yearling to sell as a ‘ready to run’ horse.

PROGENY  The offspring of a horse.

RASMUSSEN FACTOR Inbreeding to superior females through different offspring. For instance, Blue Hen mare BEST IN SHOW being duplicated in a pedigree through daughter Show Lady and son Gielgud, or daughter Monroe.

REMOVES  Generations in a pedigree.  For instance, a horse may have Star Kingdom on its third remove – that means that Star Kingdom is three generations back in the pedigree (if he was sire of the sire of the sire of the subject horse he would also be the ‘great grandsire on the tail male line’).

RIG  A male horse which has a testicle that has not descended into the scrotum.  Gelding of  a rig requires a surgical operation.

SECOND DAM  The grand-dam (grandmother) on the female side of the pedigree.

SEX BALANCED  Usually referred to when inbreeding, if the individual to which the horse is inbred (or closely linebred) appears through both a son and a daughter, it is said to besex balanced’.  For instance, if a horse was inbred 4 x 4 to Star Kingdom, through his son Biscay and his daughter Dark Jewel, Star Kingdom would be ‘sex balanced’. This is a desirable pattern for speed enhancement. 

SIRE     Father of a horse (a stallion at stud is not termed a sire in catalogue pedigrees until he produces a winner).

STALLION  Male horse over three years old which has not been castrated, also known as an ‘entire’.

TABULATED PEDIGREE  A pedigree displayed in table or grid format.  The sire is always positioned at the top of the pedigree and the dam at the bottom.

TAIL FEMALE LINE The ‘bottom line’ of a tabulated pedigree   ie the dam, second dam, third dam, fourth dam etc.

TAIL MALE LINE  The ‘top line’ of a tabulated pedigree – ie the sire, grandsire, great-grandsire etc.

THIRD DAM  The great grand-dam on the female side of the pedigree.

THREE QUARTER SISTER / BROTHER IN-BLOOD Where the dam is the same (or a full sister) and the sire is a half brother to the sire of the other horse (three of the four grandparents are the same).

THREE QUARTER SISTER / BROTHER Where a horse is by the same sire and the dam is a half sister to the dam of the other horse (three of the four grandparents are the same).

WEANLING  Horse under the age of one year (at 1st August in the Southern Hemisphere) which has been weaned from its dam.

YEARLING  A horse born after 1st August* officially becomes a yearling on the following 1st August.

* Australian rules regarding foal birth date outline that if a mare is served on 1st September or later, her foal born before 1st August the following year will be counted into the crop commencing 1st August and as such, not turning one year until the following August.


  1. Danny Kotel says:

    sex balance … does the sire need to appear through both a son/daughter or grandson/grand-daughter for that to be considered sex balanced and does that also mean that a sire (eg Danzig) appearing on the top and bottom of the page through sons only IS NOT sex balanced?

    • Hi Danny – sex balancing an individual (for instance Danzig) means that Danzig has to be represented by an immediate daughter and an immediate son. Grandson and granddaughter doesn’t count if their Danzig parent is of the same sex (ie two sons of Danzig).
      To answer the last part of your question – yes, a sire (eg Danzig) appearing on the top and bottom of the page through sons only IS NOT sex balanced.

  2. Can someone tell me if there is a relationship name for a horse whose (a) sire is the same as the other horse. (b) the sire of the dam is a full brother to the dam of the other horse. In other words six grandparents the same.

  3. Anna Riley says:

    What do you call a thoroughbred horse whose dam is the same as the grand dam of another horse. ie; Leiny by Lunar out of Veezy
    Scottie by Smokie out of Simmer by Great Scott out of
    PS… fictitious names

    • Hi Anna
      Assuming they are by different stallions as in your example, the terminology would be that the Scotty is ‘out of a half sister to Leiny’.

  4. Heather Wyllie says:

    My mare has the same dam bloodline as the stallion. Can you tell me if this is good or bad for mating please. I’m confused about the whole thing. Thank you.

    • Hi Heather – I assume you mean that the mare is from the same female family as the stallion rather than sharing the same sire line?
      If it is the same female family, it is more likely to be a good mating, however other elements in the mating have to be taken into consideration.

  5. Systematic crossing of two or more breeds in which the crossbred ewes are mated to rams of the breed contributing the least genes to that ewe’s phenotype.

  6. Many thanks.keep up the good work

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