Breeding Related Cats

[RejoiceErb]

I have a question for very experienced breeders, how closely can you safely breed purebred cats? We have a queen who carry’s Cinnamon and Dilute, we want to keep these colors in our cattery but the Queen is retiring. She has a daughter who possibly carries these colors, but would it be safe to breed her daughter to the same queen’s son who has a differant father? So the kittens would be half siblings (same mother, different father).

 

[lutece]

I would start with these questions:

• Calculate the overall coefficient of inbreeding for each cat, and for the proposed mating. Other than the proposed half-sibling mating, are these cats generally outcrossed, or are they already line bred or inbred to start with?
• Do you know the bloodlines well, and whether the cats in these lines are generally healthy? If there are any health issues in the lines (including fertility issues), they can be intensified by close breeding.
• For the next generation after the proposed half-sibling mating, will you have outcrosses available so that you can prevent further close breeding in the next generation?

I also strongly recommend that you consider using genetic testing as a tool in your breeding program!

• You can test your queen's son and daughter to see if they actually carry cinnamon and/or dilute.
• You can do genetic diversity testing, which is a GREAT way to see how inbred or genetically diverse your cats actually are.
• Genetic diversity testing would also allow you to determine the expected diversity of the half-sibling mating you are considering. This is even better than doing a pedigree analysis with coefficient of inbreeding.

For genetic testing, I would recommend Optimal Selection Feline, which is a very big test panel including genetic diversity. Or you could use UC Davis if you just want to test for the color genes (cinnamon and dilute).

If you'd like help calculating coefficient of inbreeding, send me a private message and I will be glad to help.

 

[RejoiceErb]

I would start with these questions:

• Calculate the overall coefficient of inbreeding for each cat, and for the proposed mating. Other than the proposed half-sibling mating, are these cats generally outcrossed, or are they already line bred or inbred to start with?
• Do you know the bloodlines well, and whether the cats in these lines are generally healthy? If there are any health issues in the lines (including fertility issues), they can be intensified by close breeding.
• For the next generation after the proposed half-sibling mating, will you have outcrosses available so that you can prevent further close breeding in the next generation?

I also strongly recommend that you consider using genetic testing as a tool in your breeding program!

• You can test your queen's son and daughter to see if they actually carry cinnamon and/or dilute.
• You can do genetic diversity testing, which is a GREAT way to see how inbred or genetically diverse your cats actually are.
• Genetic diversity testing would also allow you to determine the expected diversity of the half-sibling mating you are considering. This is even better than doing a pedigree analysis with coefficient of inbreeding.

For genetic testing, I would recommend Optimal Selection Feline, which is a very big test panel including genetic diversity. Or you could use UC Davis if you just want to test for the color genes (cinnamon and dilute).

If you'd like help calculating coefficient of inbreeding, send me a private message and I will be glad to help.

Well they would the same mother but other than that they would be completely unrelated. The boy’s father is imported so he has completely different lines than the daughter’s side.

All of the parents are tested and N/N for health concerns associated with the breed. As for the colors we are wanting to preserve in our lines, of course we would test the kittens to make sure they carry the colors before breeding them.

Thank you so much for the information. Any more thoughts would be very appreciated.

 

[RejoiceErb]

The goal is to produce a male carrying all of the colors and desirable traits, who can be bred to the original queen’s daughter. The only way we have to produce this kitten on our own is by breeding the original queen to an imported male.

But if we think this might cause issues in our lines, we would find another way.

 

[lutece]

Well they would the same mother but other than that they would be completely unrelated. The boy’s father is imported so he has completely different lines than the daughter’s side.

Even if the boy's father is imported, he still might go back to related cats farther back in the pedigree. What breed are you working with?

It's possible for a cat to appear outcrossed because it has no repeat ancestors in a 5 generation pedigree, but still have a high coefficient of inbreeding (over 30%) because of bottlenecks earlier in the history of the bloodlines or the breed. On the other hand it's possible for a mating that looks really close, such as a half-sibling mating, to have a relatively low coefficient of inbreeding (under 15%) if the other cats in the pedigree are truly unrelated.

I'd be happy to help you calculate COI, you could start by sending me pedigrees of the cats in private message (or links to the cats' pedigrees in an online database).

 

[lutece]

All of the parents are tested and N/N for health concerns associated with the breed.

It's great that you are testing the parents! Lots of potential health problems don't have genetic tests, however. So when I ask about how closely you know the bloodlines, I'm just asking whether you know a lot about the health and fertility of the cats going farther back in your queen's pedigree? If I were making this breeding decision, I would feel more comfortable about line-breeding on your queen if her bloodlines are generally healthy, long-lived, and fertile, without predispositions towards illness, etc. If you aren't really familiar with the lines in her pedigree, you could contact other breeders and talk to them.