Okay. This issue also confused me. I took to adding Strength to all natural attacks except where it was expressly noted in the rules that it was not. This led to some over-the-top damage codes, for example with the Tormentedīs gore attack, but hey, ever noticed the size of that horn? Being speared by the horn of a Size 3 (elephant-sized) demon actually must feel like a damage 18 attack.
With the Tusk and Ram attacks, it hasnīt led to too much trouble, but, again, the Trample damage codes tended to be over the top. Since usually, with several Goblin and Ogre Myrmadons in my army, I am the one who does the trampling, I tend not to add a Strength bonus to Trample attacks. Note that all those are house rules and not supported by FAQ or anything.
Iīm actually more interested in a ruling for those mounted models who werenīt supplied separate stats for mount and rider. Orc Kutara lancers, for example, have a Strength of 3, which I assume represents the bulk and muscle of the Kutara. Do the Orcīs falchion attacks get a strength bonus? Looking at the way real-life cuirassiers, hussars and ulans fought, Iīd say yes, since the cutting power of the strike (swinging upward, always swinging upward) gains from the added height and momentum of the horse.
With a lance, it is easier to picture, since itīs actually the mountīs momentum alone that drives the lance into the opponentīs body. One can imagine the force of the impact if one looks at historical armour when I visited the Royal Armouries in Leeds they had several suits of plate on display where the tip of a lance had gone clean through breastplate and backplate (not to mention the wearerīs body in between), sporting a hole I could have put my fist through.
On the other hand, those models who do have a split statline usually have a lower Strength stat for the rider, so it would be fair to give the Orc a strength of, say, 1 for his own attacks.
