Don't eat dogs - Inukuwazu

...This is because it was believed that dogs are fertile and have easy births, but it is also said that if a woman gives birth on the day of the dog, she will have an easy birth, and if a couple has sex on this day, she will become pregnant. Also, in wheat-growing regions, sowing wheat on the day of the dog is called "dogs do not eat," and it is disliked because it is believed that some people will die from not being able to eat the wheat. This taboo is often linked to the story of the future of grains. ...

*Here are some explanations of terms that refer to "dogs don't eat dogs."

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…これは犬が多産で産が軽いと信じられたためだが，戌の日にお産をすれば安産だとか，この日に夫婦が交われば妊娠するともいう。また麦作地帯では，戌の日に麦まきすると〈犬食わず〉といい，その麦を食えずに死ぬ者が出るといって嫌う。この禁忌が穀物将来説話と結びつけて語られる場合も多くみられる。…

※「犬食わず」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報