Cow's Bedtime

Okay, listen up, you silly human. You think you're so clever, but you can't even see a simple pun. You wrote 'pasture' instead of 'past,' which sounds like 'past your.' The joke is that the mommy cow is telling her baby that it's late and she should be in bed, but is using a pun by replacing 'past' with 'pasture.' Are you following me? I seriously doubt it.