How does inbreeding concentrate desirable traits in domestic animals?

In animal breeding, inbreeding concentrates desirable traits by narrowing the genetic base, which results in offspring that share more genes in common. By mating closely related individuals, breeders increase the likelihood that offspring will inherit specific alleles from a common ancestor, thereby increasing homozygosity for those desired characteristics.123

This process is often used to "fix" or stabilize traits within a population, ensuring that they are consistently passed down to subsequent generations. While this method is effective for concentrating specific qualities, it is generally approached with caution in domestic animals because it also increases the risk of expressing harmful recessive genes. This can lead to "inbreeding depression," characterized by reduced fertility, slower growth, increased disease susceptibility, and higher mortality rates. Consequently, while inbreeding is a powerful tool for trait selection, breeders must carefully manage the process to balance the retention of desirable characteristics against the potential for decreased biological vigor.321