Gold Strike was bred to Munnings. The foal will be inbred 3x4 to Mr. Prospector. TB breeders can please explain inbreeding?

Why would one inbreed like this? I am clueless. They inbred to get Rich Strike as well. Is this the norm?

This is totally the norm. Most commercial pedigrees have Mr P at least twice, ND at least twice – if not three or four or six times.

Typically, this kind of doubling on an ancestor is called “linebreeding”.

The reason for doing so is to consolidate the desired genetics by doubling on the ancestor with the desired traits. This makes it statistically more likely the trait you’ve selected will appear in the offspring. While the term inbreeding is often used in a negative connotation, issues only arise from inbreeding when the ancestor inbred to has negative traits (could be conformation, disposition, etc) or hidden genetic disorders – example being those that that require two copies for offspring to be affected.

The only other pitfall is when a specific stallion monopolizes the gene pool because of the success of his offspring, it can sometimes be difficult to find a match that does not have this stallion/ancestor in their pedigree. This is referred to as an “outcross” and is often done to promote genetic diversity and breed forward. A few generations down the line, they may linebreed again.

Right now, it is very common that successful race horses are linebred to Mr P and Northern Dancer. Mr P was a fantastic stallion that let the mare come through while adding a dose of speed. For that reason, many of his get and grandget (especially those linebred to him) are incredibly successful on the track.

This is not just the norm in the Thoroughbred racing world. It is very common in every breeding circle, from meat cattle to dogs - Doberman (dogs) have one of the lowest genetic diversities in dog breeds because specific sires were selected over and over again.

In warmbloods, it’s now almost impossible to find a brilliant dressage horse who is not at least linebred to Donnerhall and Weltmeyer – two incredible stallions that revolutionized more than one registry with their incredibly talented offspring.

It is not a bad thing, but it must be done while looking forward.


Having a closed stud book, TB’s will always have common ancestors. They did a good job of limiting Mr. Prospector in their choice of Munnings, Holy Bull is an outcross to just about everything.

This Munnings/Gold Strike foal “to be”, will not be unusual as TB pedigrees go, and 3 x 4 to Mr. Prospector isn’t an issue.

Rich Strike’s pedigree however, is not the norm at all.


Great explanation of critter breeding 101 @beowulf. :smile:


3x4 to a major stallion is so common in TBs it would hardly register with me. Likely, those who planned this mating didn’t sit down and say, “Let’s go for 3x4 Mr P!” They probably said, “Munnings is hot right now, he complements her physically, and we can get a deal.” Many matings also rely heavily on what also works with the female family; I did some digging and couldn’t find anything specifically promoting Munnings/Speightstown with her, but it’s usually a consideration. Apparently Munnings also has a good nick with Mr P line mares, which TrueNicks probably gives a great grade via Smart Strike. Some breeders rely heavily on the nicking sites and variants; I think of them as a bonus, but you have to look closely at how the grades are collected and I always give weight to the specific female family with sirelines vs sireline over sireline alone.

For example, we purchased a mare in January named Magical Mist (by Congaree). Her half sister Magic Appeal is the dam of Letruska (by Super Saver). Super Saver is gone, so we decided to breed her to Runhappy (by Super Saver) trying to capitalize on a sireline that has worked well (!!) in that female family. There isn’t any notable inbreeding here (5x5 to ND), but even if there was 3x4 to someone I would still try to bank on the Super Saver sireline. (And Runhappy is no slouch either!) That female family LOVES Successful Appeal, and if there was a good commercial sire by him (or other Valid Appeal son) that would be a no brainer…but Runhappy/Super Saver is the next best thing.


Have you seen a conformation shot of the mare? I haven’t, but I haven’t looked very hard to find one. I hope they got “a deal” for Munnings, because they bred late. I’d guess that the decision would have been after the Derby win by Rich Strike, which would have been May or June, so late in the season.

Otherwise it makes no sense to put this mare to Munnings for an 85K fee.

20 yr old mare, so better late than never must be the thought?.

Not a good one…

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I’m not a conformation expert, but is that an unfortunate hind end or just the angle/placement?

Looks like she’s under in both of these.

As far as why she was bred so late… she was given to a new owner the Monday before the Derby and wasn’t in his possession until the Wednesday before the derby. So, it was a holy moly we might have a broodmare worth something situation.


Those definitely look better. Must have been a bad angle. Thanks.

You pay nothing until the foal is on the ground (or until you sell the mare), so the time of year is irrelevant to the cost.

Better late than never is absolutely right in this case. A valueless mare is suddenly producer of a Kentucky Derby winner.


100%. At age 20, this could be her last foal so why not swing for the fences and breed up as much as you can. It doesn’t look bad for Munnings either to have a KY Derby producer on his book! With a mare like this it wouldn’t be out of the question to work a foal share deal, or pay with proceeds after it sells.


Yes, I understand LFG but thought they might get a “deal” especially since she did produce a KD winner and apparently his book wasn’t full. He’s pretty popular now though…

I wonder if they’ll keep or sell ? It will be a May or perhaps June foal. Do you think they will try selling the mare in foal? I can’t imagine which would be the best way to go for them, business-wise. I suppose it will depend somewhat in how Rich Strike does in the Belmont.

Too bad Animal Kingdom was exported. He’s a good outcross stallion and his daughter Regal Glory is a stunning filly. Her win today was wonderful.


Jack Christopher, by Munnings, just won the GR1 Woody Stephens in spectacular fashion.


There are many stallions I am bitter about the US losing. Animal Kingdom is one of the highest on the list.