Additional damage inherits all of the properties of the base damage.
101925
Tainted Spring
Only usable as an action to recruit or employ an animal is announced.
If this action is successful, the animal gets +1 strength (for an ally) or inflicts +1 damage (for damage-dealing retainers).
As above, and the animal gets 1 additional starting life.
Rulings
Must be played (as well as other "as the action is announced" action modifiers) before action modifiers that are not explicitly played "as the action is announced" (e.g., Conditioning).
Replace the action card (if any) before playing it.