$products = Mage::getModel('catalog/product')->getCollection()
    ->addAttributeToSelect('breed','other_field');

$products->getSelect()
    ->order(new Zend_Db_Expr('e.breed asc, e.other_field desc'));

foreach($products as $product) {
    var_dump($product->getData());
}

SELECT `e`.`entity_id`, `e`.`type_id`, `e`.`attribute_set_id`, `e`.`breed`, `e`.`other_field` FROM `catalog_product_flat_1` AS `e` WHERE (e.status = 1) ORDER BY `e`.`breed` asc, `e`.`other_field` asc