Before the 30th day of gestation, there is no bone formation, so it is reabsorbed. Thus, reabsorption occurs from the first week to the third post-mating week with a return to heat.
We begin by defining the problem: When do sows abort? Are abortions occurring above normal levels? In that case … How much? Is it seasonal? What is the incidence pattern? Is there some kind of relation with other variables?
Abortions often cause scaremongering. However, we must bear in mind that during the first days of gestation – before the calcification process – it is possible to have embryonic losses. These are not observed since a reabsorption phenomenon subsequently occurs and they generate a repeated bristle (what we commonly call “cyclical”, “cyclical” or “empty”).
During the second week, hormonal changes are also very common and have a direct impact on gestation. A very notorious effect is the change in the corpus luteum that produces high levels of progesterone and can lead to miscarriage
We must avoid moving the sows in the first 35 – 40 days of gestation, as well as covering sows in a catabolic state (when they have less than 10mm of backfat thickness).