How to determine % of xx/ox

[Marigold]

Starting my first thread and hoping COTH can help answer a question. Here’s the hypothetical situation:

• Horse A is unlisted in HorseTelex
• Sire is listed with an XX/OX rate of 41.60%
• Dam is full TB

How could someone approximate the blood percentage in Horse A? Is it as simple as multiplying 41.60% by the 100% of the dam?

A second hypothetical situation:

• Horse B is unlisted in HorseTelex
• Sire is listed with an XX/OX rate of 41.60%
• Dam is a TBxSport Horse, also unlisted in HorseTelex.

I’m guessing it’s safest to assume that the mystery “sport horse” in the dam doesn’t contribute. For working purposes, does that make the dam’s XX/OX rate 50%? What does this make Horse B?

I’ve never really looked into the calculation, and of course I can’t find anything online. Is this simple multiplication, or are there other factors I’m overlooking?

Any help from the experts here would be appreciated!

[D_BaldStockings]

[QUOTE=Marigold;8951962]
Starting my first thread and hoping COTH can help answer a question. Here’s the hypothetical situation:

• Horse A is unlisted in HorseTelex
• Sire is listed with an XX/OX rate of 41.60%
• Dam is full TB

How could someone approximate the blood percentage in Horse A? Is it as simple as multiplying 41.60% by the 100% of the dam?
Add 41.6 and 100 = 141.6 then divide by 2 = 70.8%

A second hypothetical situation:

• Horse B is unlisted in HorseTelex
• Sire is listed with an XX/OX rate of 41.60%
• Dam is a TBxSport Horse, also unlisted in HorseTelex.

I’m guessing it’s safest to assume that the mystery “sport horse” in the dam doesn’t contribute. For working purposes, does that make the dam’s XX/OX rate 50%? What does this make Horse B?

[B]Assuming the dam has at least one TB parent, her 5 must be at least 50%. her WB parent is assumed to be a blank.
the Sire is 41.6 + dam of 50 = 91.6 divided by 2 = 45.8%

[/B]I’ve never really looked into the calculation, and of course I can’t find anything online. Is this simple multiplication, or are there other factors I’m overlooking?

Any help from the experts here would be appreciated![/QUOTE]

If you have actual pedigrees on the horses in question that are not TB/OX and they are entered in horsetelex you can use their figures to recalculate the additional TB percentage, basically it halves for each generation back in the pedigree.

If the horses are unregistered, the results are meaningless since they can’t be verified; so you should not state that your horse is any %.

[Marigold]

[QUOTE=D_BaldStockings;8952174]
If you have actual pedigrees on the horses in question that are not TB/OX and they are entered in horsetelex you can use their figures to recalculate the additional TB percentage, basically it halves for each generation back in the pedigree.[/QUOTE]

Thank you for this, that’s very helpful! If I don’t have a percentage for the dam, but know she was half TB, to be safe could I use 50% (ex. conservatively estimating that the non-TB half did not contribute), or is the calculation not that simple?

And just to take that a little further to make sure I understand your point, if the sire is 41.6%, he would contribute 20.8% (that would be his “half” as he is a generation back) and the dam, if theoretically 50% xx/ox, would contribute 25%, thus making the foal at least 45.8%. Is that approximately correct?

@D_BaldStockings;8952174

If the horses are unregistered, the results are meaningless since they can’t be verified; so you should not state that your horse is any %.

Thank you for the warning. To clarify, this is not a question I’m asking because I’m going to put this information in a sales ad. I just want to be able to approximate this for myself (roughly) when evaluating event prospects if the full breeding is unlisted. I really appreciate the help!

[zipperfoot]

IIRC XX on horsetelex includes Arabians and Anglo-Arabians as well as TBs. For example, my yearling filly by Ironman out of my TB mare is about 70% XX but about 14% is actually Arabian (at least if my math is correct…).

[D_BaldStockings]

[QUOTE=Marigold;8952878]
Thank you for this, that’s very helpful! If I don’t have a percentage for the dam, but know she was half TB, to be safe could I use 50% (ex. conservatively estimating that the non-TB half did not contribute), or is the calculation not that simple?

And just to take that a little further to make sure I understand your point, if the sire is 41.6%, he would contribute 20.8% (that would be his “half” as he is a generation back) and the dam, if theoretically 50% xx/ox, would contribute 25%, thus making the foal at least 45.8%. Is that approximately correct?

Thank you for the warning. To clarify, this is not a question I’m asking because I’m going to put this information in a sales ad. I just want to be able to approximate this for myself (roughly) when evaluating event prospects if the full breeding is unlisted. I really appreciate the help![/QUOTE]

Note that a horse with 2 grandparents TB (where both parents are TB-X) will have the same blood % of 50% as a horse with one TB parent. However this does not mean that the genes and resulting characteristics of the Grandparents were transmitted reliably through the half-blood parents.

Also mitochondria are transmitted from the dam in tail female fashion. This has to do with athleticism.

[Marigold]

[QUOTE=D_BaldStockings;8953710]
Also mitochondria are transmitted from the dam in tail female fashion. This has to do with athleticism.[/QUOTE]

I didn’t know that, thank you Stockings! And more generally, thank you for taking the time to discuss this - it’s tough to find the information online, but very informative