Frankly, I don't live in a major tobacco area, I don't smoke, in fact I have asthma to smoke (and pigs!) so I'm not big on tobacco to begin with, but it is a known teratogen, which means it causes birth defects when fed to cattle or pigs at higher levels. What's not certain is what happens at lower levels... Add in all the carcinogens in the stuff and frankly, I'd prefer insecticides going into the cattle. If someone is organic and feeding the stuff, consider diatomaceous earth. They're both only marginally effective but at least DM is safe to the fetus!