WP_Query not returning custom fields

<?php
    $keys = array('Show Date','Birth Year','Origin');

    echo '<table>';
    echo '<tr><th>Title</th>';
    foreach( $keys as $key ) {
        echo '<th>' . $key . '<th>';
    }
    echo '</tr>';

    $myquery = new WP_Query( 'post_type=post' );
    if( $myquery->have_posts() ) : while( $myquery->have_posts() ) : $myquery->the_post();

        $title = get_the_title();
        echo '<tr><td>' . $title . '</td>';

        $values = array();
        foreach( $keys as $key ) {
            $values[] = get_post_meta($post->ID, $key, true);
        }
        foreach( $values as $value ) {
            echo '<td>';
            echo $value;
            echo '</td>';
        }
        echo '</tr>';

    endwhile; endif;

    echo '</table>';
?>