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ARTICLES

Breeding Black Spanish Horses in Australia


Published in the 2008 January edition of the NSW Branch AHAA Magazine

I often receive emails or phone calls from people inquiring about buying black horses or breeding black horses. I do not profess to be an expert however apart from having a degree in Applied Science Majoring in Equine studies and holding numerous certificates in horse colour genetics, I have been breeding black horses for many years. I have no intentions of trying to explain the factors that lead to black colour intensity as this is a more complex study, but I can explain the very basics of black colour breeding that I use in my breeding program at Black Horse Manor. The percentages I quote are only estimates as maths is not one of my strong points!

Firstly there are a couple of terms and concepts that are required to be understood in order to understand black colour breeding. They are:

  • Genes come in pairs called alleles.
  • Each parent contributes one gene/allele to a pair.
  • Dominant – A dominant gene/allele is written as an upper case letter. This means the gene/allele will mask the presence of a recessive gene eg. AA or Aa is dominate over aa.
  • Recessive – A recessive gene/allele is written as a lower case letter. This means a recessive gene/allele will only be expressed in the absence of a dominant gene eg. ee or aa
  • Homozygous – this means the genes (pair of allele) are the same. Unless masked, homozygous traits are general expressed. As each parent contributes one gene or allele, homozygous is demonstrated by 2 identical lower or upper case letters – eg AA or ee.
  • Heterozygous – this means the pair of genes/alleles contains one dominant (upper case letter) and one recessive (lower case letter) gene/allele. Either parent can contribute the dominant or recessive gene/allele eg. for Aa the father could pass on the A and the mother could pass on the a or visa versa.
  • EE, Ee or ee are the genes associated with the chestnut or red factor colour
  • AA, Aa or aa are the genes associated with the black and bay colour (agouti).
  • Bay is Aa or AA and black is aa. Bay is dominant to black.
  • Chestnut is ee and non chestnut is EE or Ee.
  • Chestnut masks bay.

There are 4 main colours that I try to understand in my black breeding program as these are the colours most relevant to the Spanish Horse. The following are the colours with their corresponding genetic alleles:

  • Black - aaee
  • Chestnut –AAee, Aaee, or aaee (liver chestnut),
  • Bay – AaEe, AAEe or AAEE
  • Grey –GG or Gg. Non grey is gg.

Grey in fact is not a colour and in very simple terms, it is a modifying gene which changes a base colour (black, chestnut or bay) over a period of time to grey. Shades of grey, dapples and the length it takes to turn grey are all influence by various other modifying genes.

Using Black to Breed Black

Obviously my preference for breeding black is to use black horses however black Pure Spanish Horses, especially mares are rare in Australia (and good ones even rarer). Black horses can be genetically tested to see if they are homozygous however this test is only available from America at this stage. Not many black Spanish horses in Australia are homozygous.

  • aaEE x aaEE (both parents are homozygous black) =100% homozygous black
  • aaEE x aaEe (heterozygous black) = 50% homozygous black and 50% heterozygous black
  • aaEe x aaEe (both heterozygous) = 25% liver chestnut, 25 % homozygous black and 50% heterozygous black.
  • If a black horse throws a chestnut to any colour, then it is not homozygous black.
  • If 2 black horses produces a bay foal then one or both parents is not black.

Using Bay to Breed Black

When using bay to produce black it is very important to research the horse’s pedigree and try and ascertain if it is a heterozygous bay. Homozygous bays will not produce black. Obviously without a genetic test it is hard to know for sure if a horse is heterozygous or homozygous however by studying the colours behind the horse and colours of any offspring, will give you a very good indication. Heterozygous bay can produce the following:

  • AaEE (bay) x aaEE (homozygous black) = 50% homozygous black and 50% heterozygous bay
    AaEe (bay) x aaEe (heterozygous black) = 37.5% bay, 25% heterozygous black, 12.5% homozygous black and 25% chestnut.
  • AaEe (bay) x AaEe (bay) = 55% bay (25% homozygous bay, 30% heterozygous bay), 25% chestnut and 20% black.
  • AaEe (bay) x AaEE (bay) = 75% bay (25% homozygous bay, 50% heterozygous bay), 25% black (50:50 hetro/homo) and no chestnut.
  • AaEE (bay) x AaEE (bay) = 25% homozygous black, 25% heterozygous bay, 50% homozygous bay and no chestnuts.

Using Chestnut to Breed Black

Chestnut is a wildcard as it masks the colour bay. People who wish to breed black horses often fall into this trap. The horse can in fact be homozygous for bay however the action of ee masks the AA. The only chestnut that gives 100% chance of producing black is a liver chestnut. Lets look at combinations:

  • AAee (chestnut) x aaEe ((heterozygous black) = 50% chestnut, 50% heterozygous bay and no black.
  • AAee (chestnut) x aaEE (homozygous black) = 100% heterozygous bay, no chestnut or black.
  • Aaee (chestnut) x aaEE (homozygous black) = 50% heterozygous bay and 50% heterozygous black.
  • Aaee (chestnut) x aaEe (heterozygous black) = 25% heterozygous bay, 25% homozygous black, 25% heterozygous black and 25% chestnut.
  • aaee (liver chestnut) x aaEE (homozygous black) = 100% black – 50% homozygous and 50% heterozygous.
  • aaee (liver chestnut) x aaEe (heterozygous black) = 25% homozygous black, 50% heterozygous black and 25% chestnut.

Using Grey

Now when you add the colour grey into the equation it is very important to know what the base or foal colour of the grey is. It is also very important to know if your horse is homozygous grey (GG) or heterozygous grey (gg). Remember, homozygous grey to any colour will always produce grey. Grey is also a colour that can be bred out, so if a solid is produced by either 2 grey parents or one grey-one solid parent, then you must breed that offspring back to a grey to reintroduce grey (using a homozygous grey - 100% chance, using heterozygous grey - 50% chance). Some of our nicest black Pure Spanish stallions in Australia are actually a result of heterozygous grey x heterozygous grey.

It is with this knowledge that I made the decision to import the heterozygous grey Pure Spanish mare, Kenia-FC from Spain as I could not afford to purchase a black Pure Spanish mare/filly. In Kenia-FC’s case her father is black and her mother is grey. This makes Kenia-FC genetically aaE_Gg or aaEEGg and gives me a 50% chance of producing a solid colour (black or chestnut). I actually believe that Kenia-FC is aaEEGg thus 50% chance of producing black only, however the only way to be 100% sure of this is to have her genetically tested.

Black Horse Manor’s resident stallion is the imported black stallion Galero XIV, who I believe may be homozygous (yes I know this is only a guess!). This means I have a 50:50 chance of having a solid black foal from the cross with Kenia-FC. So far Kenia-FC has given me one gorgeous filly by Galero XIV that was born jet black but is now turning grey. So you see I drew the wrong 50% and produced grey! However every mating is a new 50:50 chance so one day I will produce a black foal that will stay black. These foals are usually born a smokey colour rather than jet black at birth.

Using Other Colours for Breeding Pure Spanish Horses

I personally do not consider a Spanish horse that is claimed to be buckskin, cremello, perlino, palomino or any other dilute colour, as these colours require the action of a dilute gene and as far as my research goes, the dilute gene only exists in Lusitanos and Spanish/Lusitano crosses. Dun and roan are other colours I do not consider as they too require specific genes to be present. (do not confuse roan with ticking or roaning caused by the sabino gene). Until scientific research demonstrates anything different, I am unlikely to change my point of view on this. Sometimes a bay will display physical markings of a buckskin or dun, however if you have a good look at the pedigree it will in fact genetically be just a bay. These dilute, dun or roan genes do not just appear – they have to be carried and introduced by either/both parent! These colours may have existed in the Pure Spanish Horse in the turn of the century however where bred out years ago.

In my derivative breeding program I will use these colours as I am only concerned with breeding performance horses and colour is not a factor. In fact I have a super black and white paint mare due in foal to Galero XIV (Imp) in February 2008, and I am praying for a black and white 1st cross filly!

Quality

Although I have a focus on black breeding at Black Horse Manor, I will never compromise conformation, temperament or movement for colour. I am proud of my band of broodmares and I am confident that any black Pure Spanish Horse I produce is of the highest quality. It is this reason that I in fact only have a small number of black Pure Spanish broodmares as good quality ones are hard to find and too expensive to import. So if you are trying to breed black (or any colour for that matter) you must never compromise on quality for colour.

Conclusion

The only way to be 100% certain to breed black Pure Spanish Horses is to breed a homozygous black to a homozygous black – everything else is just chance. You can however slightly tip the odds in your favour by understanding the mechanics behind colour breeding. This goes for any colour breeding – you just have to be patient. I have only supplied a very simple explanation, so if you wish to know more I thoroughly recommend the following colour calculator website and 2 books:

  • www.animalgenetics.us
  • Bowling, A (1996) Horse Genetics. University Press: Cambridge, UK
  • Gower, J (1999) Horse Colour Explained – A Breeder’s Perspective. Kangaroo Press: Roseville, NSW.

If you wish to ask me any questions please address them to the Secretary of the NSW branch of the AHAA and I will provide the answer in the next newsletter. Remember, the above is only the logic used by us at Black Horse Manor – other breeders may have their own beliefs.

 

Sabina Callaghan BA Applied Science Equine.
Black Horse Manor Pure Spanish Horse Stud
www.blackhorsemanor.com.au