If there are glow plugs in the combustion chamber. The tractor has a pre-combustion chamber design, not open chamber.
Quoting you post which does state glow plugs.
Quote "I've got several of each, come on over and try them for your self. I can go out and crank up my loader tractor in any weather we have, including -5*, no glow plugs or anything else, all it needs is a good batt... Climb on, turn the key and it will start... Bet you none of my gas tractors will start that fast...
That's why I like "direct" injected diesels instead on "indirect" injection. Direct will start easier in the cold and you don't have to use the glow plugs..." Unquote
Also if you think the glow plugs are not energized while cranking, you don't know what is going on.