Why use deber for this

Question

Why conjugate deber in the conditional and not the verb that is an infinative? Like instead of 'El pastor debería cuidar a las ovejas', have it be 'El pastor cuidaría a las ovejas'?

Silvia Píriz · Accepted Answer

Hola Sidney O.
That's a great question!
The reason we conjugate deber in the conditional rather than the main verb is that deber + infinitive is a structure used to express obligation, advice or recommendation.
Let's compare your two sentences:
El pastor debería cuidar a las ovejas. = The shepherd should look after the sheep.
El pastor cuidaría a las ovejas. = The shepherd would look after the sheep.
In the first sentence, debería expresses what the shepherd should do. The verb cuidar remains in the infinitive because it follows the conjugated verb deber.
In the second sentence, cuidaría is the conditional form of cuidar, expressing what the shepherd would do, usually under certain circumstances.
So, although both sentences use the conditional tense, they convey different meanings:
Debería cuidar = should look after (advice or recommendation)
Cuidaría = would look after (hypothetical action)
I hope this helps clarify the difference!
Saludos
Silvia