What does the term "inbreeding" mean in animal pedigrees?
Inbreeding in animals happens when the same ancestor appears multiple times in a pedigree through different children or offspring. Due to the sheer numbers of animals in any given pedigree, it's bound to happen as you move further back in any animal's history. In small specialized or closed populations such as specific dog breeds, it ends up happening quite frequently.
How is inbreeding displayed on a pedigree chart?
Inbreeding is shown in pedigree reports via colored boxes on the right side of an animal's pedigree cell. Each ancestor that's inbred will show up with the same colored box in the pedigree chart so that you can easily spot duplicate animals in the pedigree. If you hover over any of the colored boxes, you may see a message that looks like this: 4S x 3s x 5D. This message contains information about where the inbreeding occurs and also the sex of the offspring. In the above example, the inbreeding would have occured three times, with info about each occurrance separated by the 'x'. The first occurance 4S appears in the fouth generation (4) on the sires half of the pedigree (S stands for sire), through a male offspring (because the 'S' is capitalized). The second occurance 3s appears in the third generation, on the sire's side of the pedigree, but this time through a female ancestor because the 's' is lowercase. The final inbreeding 5D happens in the 5th generation on the dam's side (D stands for dam) through a male offspring because the 'D' is capitalized.