Hello, I am in need of assistance in making vanilla mobs, (pig,cow,chicken,etc..), hostile when attacked.

Then I would suggest you @ForgeSubscribe and use onEntityAttackEvent and extends it about your own way. Good example of how this works is almost similar ThaumicTinkerer onLivingDropEvent or somewhat like that. I did not remember right and exact names, but... This should be pretty helpful

If you are developing for 1.7.2+, I believe you should use @SubscribeEvent instead of @ForgeSubscribe.

This is what I have so far, not entirely sure where I go from here.

@SubscribeEvent
    public void hostileMobEvent(AttackEntityEvent event) {
    	if (event.entity instanceof EntityAnimal) {
    		entity.
    	}
    }

Does anyone have any suggestions as to where I head from there?

You can change the AI of vanilla mobs directly.  However, passive animals don't have a targetTasks list, so I don't think it would be easy to add hostile AI tasks. 

 

So I think what you want to do is create your own custom EntityHostileCow, EntityHostileSheep, etc. that extend the original passive animal.  But you would add target AI tasks similar to what hostile mobs have.

 

Then you would handle the LivingSpawnEvent, and if the event.entityLiving instanceof EntityCow you'd replace it with your EnityHostileCow, and so forth.

 

If your custom classes extend the vanilla ones, then they should generally be treated as the original, except the AI would be different.  Note that to successfully attack a mob also needs to register an attackDamage attribute.

 

 

I am trying to make my custom entity look like a cow. In 1.7.2 forge, what is the method that I need to call?

This is what I have so far, I am looking at making a cow act like a zombie. For this, I am creating a custom entity like you said, and then altering it to appear and sound like a cow.

 

public class TSTweaksCow extends EntityZombie {

public TSTweaksCow(World par1World) {
	super(par1World);
}
}

 

How would I go about loading the model.

You should extend EntityMob and add the AI tasks you want!