get_posts sub taxonomies

Hi im reading the codex and found this example

If specifying a category from a custom post type then instead of using ‘category’ you would use ‘{your_custom_post_type}_category’. For instance, if you had a custom post type called “dogfood” and wanted to only show posts from the category “brand” you would use the below code.

<?php
$args = array(
   'numberposts' => 8,
   'orderby' => 'rand',
   'post_type' => 'dogfood',
   'dogfood_category' => 'brand',
   'post_status' => 'publish'
);
$show_brands = get_posts ( $args );
?>

i tried to implement that in my site to make a list of the recent post, but i need a sub category of my custom taxonomy to stay in the example of the codex i need from dogfood only the “pedigree” brand how can i call it?