In a first analysis, in which all the females were
included (n = 505), the occurrence of a reproductive failure
in the preceding mating was investigated as a risk factor
for the recurrence of a return to estrus. After this, 36
females with previous reproductive failure (32 with return
to estrus and 4 with abortion) were excluded and the effect
of parity order (PO0, PO1, PO2 and PO>2) was then
investigated in 469 females