BrutalAttack, you are so arrogant...Re: Additive means in addition! You should have read the article, as it wasspeaking to the lowered pregnancies, not to calf mortality. According to this article, the healthy ratio is way above what seems to be found in areas a wolf population,such as the Park. NO herd can sustain itself with the numbersstated in this article, let's hope the numbers are wrong.....