Because only the chromosomes can be seen in a karyotype, and microdeletions or insertions are mutations at the molecular level, it is virtually impossible to detect such mutations at the chromosomal level.
Hybrid inviability is when a hybrid animal is biologically unable to grow up to be a healthy mature adult. This condition results in isolation from hybrids and pure breeds.
Hybrid infertility is a conditio experienced by hybrid animals when they cannot reproduce. This prevents the spreading of the hyrbid species into uncontrollable populations.