Feeding a cow with roses does not get extra appreciation meaning

Proverb "Feeding a cow with roses does not give extra appreciation" means that you shouldn’t waste your effort and time on people who can’t grasp the meaning and effort of your action to appreciate it enough. In short, we could say that it means that you shouldn’t waste your time on someone who doesn’t deserve it. Similar proverb can be "Casting pearl before swine" which originated in Bible (Matthew 7:6, Jesus’s Sermon on the Mount).