What does slim tell carlson to take with him when goes to shoot candys dog?

Slim asks Carlson to take a shovel with him when he goes to shoot Candy's dog because he was being careful and understanding towards Candy's dog's death. He reminds Carlson to take a shovel to hint to Candy that 'It's alright, He's going to get a proper burial' and was intended to make Candy feel better.