Ask: sow oestrus is slow, give birth to stillbirth, what does mummy fetal reason have? What's the best way?

What are the reasons why sows are sluggish in estrus, stillborn and mummified? Is there any good way to get back to life? There is no way to be small-there are many reasons, you can search the website for related posts. -- Nutrition is the level and way of thinking. How many Dushu lakes are there in the US military?