We studied, for several years, the application of Bruce effect (Bruce effect, Bruce 1959, Nature, 184, 105) on the breeding management practice resulting in blocking of implantation or pregnancy termination in domestic animals, for example horse and dog. We concluded that four situations exist that can block female reproduction (Bartoš et al. 2021 Mammal Rev. 51: 143-153). These four situations are defined by a combination of two factors: 1) when (before or after the implantation of blastocyst); and 2) how, with respect to the presence of nonsire male (contact or non-contact effects), which may be fundamentally important for the prevention of reproductive failure in breeds. We, therefore, propose a general term “effect of nonsire male’s presence”: “An effect of a nonsire male’s presence or his odour on a mated or pregnant female causing her pregnancy block or disruption” (Bartoš et al. 2022, Anim. Behav.).