What Can it be cosidered a reproductove Loss?
Return to estrus, abortion and not in pig sow.
Whats is a return to estrus?
As the name says it's when a sow is mated however the mate fails and she goes back to estrus.
Whats is an abortion?
It is defined as a birth /eviction os the litter before the fisiological time of delivery of the sow.
What is "not pig in sow"?
Not pig in sow , also known as a pseudociesis it's whan a sow's body resposd to all simptoms of a real pregnancy. There are hormonal changes, visibble fisics alterations such as lactation and a variation on the sow's behavior all matching with pregnancy behaviors.
(https://www.agrolink.com.br/saudeanimal/artigo/suinos----a-falsa-gestacao-_49554.html))
What is a Skip Heat?
It is whan the sow is heated but by choice it will not be mated. That can happend after an abortion, After a delivery and the sow is not ready (strong enough) for a new pregnancy or any other specific reason that it will not be mated, but it will wait to the next cicle 21 days after to mate it.
(https://academia.agriness.com/arquivos/tutoriais-s2/s2_tutorial_salta_cio.pdf)