Agriculture, cattle-tending, and trade are the duties, of the Vaishyas. While service of the (three) twice-born classes is the duty, 0 king, of the Shudras.
कृषिश्च पाशुपाल्यं च वाणिज्यं च विशामपि। द्विजानां परिचर्या च शूद्रकर्म नराधिप॥