Fertilization in the Bitch

The first division of the zygote takes place almost immediately, becoming 2, then 4, then 8 cells and so on. And approximately 7 days after ovulation or 4 days after fertilization, a cellular mass called morula forms and, 24 hours later, passes to the uterus. The morula is an undifferentiated embryo of between 36 and 64 cells.

Thanks to important scientific studies, they have been able to confirm that in most cases this sequence of events begins with the highest level of estriadol, and continues with the increase of LH, giving way to ovulation, first and then, if it is the case, fertilization and the primary development of the embryo. However, in some females who behave significantly different than the others, there can be a variation in the number of days that it takes (4 or 5 days before or later) for the levels of LH to show up at the beginning of the estrus period.