Question

Why is it more difficult to estimate heritability in humans than in livestock or laboratory animals?

Answer 1

Humans have always interbread with other groups and tribes, but grazing animals don't do that, so It is much easier to estimate it.

Answer 2

It is more difficult to predict heritability in humans in comparison to laboratory animals or livestock is because humans cannot be used in the selective breeding experiments, which the animals go through. The artificial selection or the selective breeding refers to a procedure in which the laboratory animals are bred for a specific phenotype or trait. This procedure has been long used in experimental medical research.