Most varieties grown in North Carolina, and throughout the US, will contain substantial levels of gossypol. Non-ruminant animals such as poultry and swine can't handle much gossypol before toxicity signs develop. This is why cottonseed meal can't be used at high levels in rations for those animals. Cattle have the ability to detoxify gossypol because the microorganisms in the rumen bind it so it can't be absorbed. This ability can be overcome at very high levels of cottonseed feeding, but cattle will not normally be affected at recommended feeding levels.
Toxicity causes primarily heart damage, and deaths due to heart failure have been reported.
Most cases, however, have usually been when cattle have been allowed to consume a lot of seed over a long period of time. This problem has largely been solved by using the cottonseed in total mixed rations rather than feeding it separately. Toxicity has also been reported in young calves fed several pounds of cottonseed per day. It is not recommended that calves be fed cottonseed before they have a well developed rumen. These problems have been seen primarily in early weaned calves.