Cottonseed is the seed of the cotton plant, formed inside the cotton boll. Cottonseed is the source of cottonseed oil and cottonseed meal. Cottonseed, like the rest of the cotton plant, contains high amounts of gossypol that can be toxic to humans. Cottonseed has been historically used as an ersatz protein-rich food in cotton-producing regions, but the modern biofortification of cotton cultivars with tolerable gossypol levels has particular relevance to impoverished cotton producers.

Cottonseed develops from the ovules within the locule of the cotton boll, a botanical fruit. Removed from the boll, seeds are initially covered in fine cotton linters, growing from the seed coat. Once the linters are removed, the seed is a brown ovoid weighing about a tenth of a gram.

The cotyledon makes up 60% of the weight of the seed without linters, the seed coat 32%, and the remaining 8% the radicle and hypocotyl. The chemical composition is 20% protein, 20% oil and 3.5% starch.

For unit weight of cotton fiber, about 1.6 units of seeds are produced. The seeds are about 15% of the value of the crop and are pressed to make oil and used as ruminant animal feed. About 5% of the seeds are used for sowing the next crop.

Cottonseed is crushed in the mill after removing lint from the cotton boll. The seed is further crushed to remove any remaining linters or strands of minute cotton fibers. The seeds are further hulled and polished to release the soft and high-protein meat. These hulls of the cottonseed are then mixed with other types of grains to make it suitable for the livestock feed. Cottonseed meal and hulls are one of the most abundantly available natural sources of protein and fiber used to feed livestock.

Cottonseed as supplement is marketed primarily towards agricultural sectors that feed dairy cows. Some feedlots use corn to supplement the forage diets of cows; high starch diets, such as those in corn supplemented diets, can lead to liver damage in cows. Cottonseed is considered a safer alternative to corn supplemented diets due to its low starch content. Cottonseed as livestock feed must also be monitored for safety since the foodstuff is high in energy/fat and too much fat content in a cow's diet can disrupt its ability to digest fiber, leading to other complications.

Cottonseed meal

Cottonseed meal is a good source of protein. The two types of meal extraction processes are solvent extraction and mechanical extraction. Most of the meal is extracted mechanically through cottonseed kernels. The flaked cottonseed kernels are put under high pressure through a screw inside a constantly revolving barrel. The screw pushes out the oil through the openings made in the barrel. The dry pieces left in the barrel are preserved and ground into meal. During the solvent extraction process, the cottonseed kernels are subjected to fine grinding by pushing them through an expander and then the solvent is used to extract most of the oil. The solvent-extracted meals have a lower fat content of 0.5% than the mechanically extracted meals with a fat content of 2.0%. Cottonseed meal contains more arginine than soybean meal. Cottonseed meal can be used in multiple ways: either alone or mixed with other plant and animal protein sources.