During rain and heavy raining season, take a look at the sow, if there are any signs of this kind of wound, especially a pregnant sow which has slat plaster under the body.
As observed, these are insect bites while sleeping, whether they are cockroach or crickets called umbical insects. Check it out.
If any insects found, quickly kill the insect because it causes stress and insomnia it is a higher risk especially on pregnant sow. If there is a lot of insect wounds found, it may cause the piglets to be born with lesser weight.
Cr: Mr. @Chutimet Deeying Academic The International Technical and Academic Center