Written by: Dr. Jacquie Jacob, University of Kentucky
With each 100 lb. of fiber produced, cotton plants produce about 155 lb. of cottonseed. Less than 5% of the cottonseed produced is saved for the following year's crop. There are multiple agricultural uses for the remaining cottonseed. Whole cottonseed meal can be fed to ruminant animals such as cattle, goats, and sheep. Oil can also be extracted from the cottonseeds. (Before World War II, cottonseed oil was the major vegetable oil produced in the United States.) Cottonseed meal is a by-product of oil extraction that can be used in poultry feed.
Cottonseed meal has less crude protein, dietary energy, and lysine content than more-conventional soybean meal. Cottonseed meal also contains the antinutritional factors of gossypol and cyclopropenoid fatty acids (CPFA). However, new glandless cottonseed meals have been developed that contain almost no gossypol, making cottonseed safer for poultry to consume.
The proportion of cottonseed meal appropriate for a bird's diet depends on the type of bird.
Research has shown that if they are supplemented with lysine, broiler diets can be composed of up to 20% low-gossypol cottonseed meal. Cottonseed meal contains approximately 40% crude protein, although the levels of protein vary depending on the extent to which the hulls are removed before oil extraction. Although the protein level is high in cottonseed meal, the protein level is low in lysine.
During the rearing of broiler breeder pullets, it is necessary to restrict feed consumption to prevent meat and body-fat deposition, which can adversely affect a bird's subsequent reproductive efficiency. Because cottonseed meal has a low nutrient density, it can be added to the diets of broiler breeder pullets to reduce the severity of feed restriction required during the laying period. The use of cottonseed meal as the main protein source in growing diets for broiler breeder pullets has been shown to improve flock body-weight uniformity with no subsequent loss in laying performance.
In the past, the nonuse of cottonseed meal for the diets of laying hens had been due to the gossypol found in the pigment glands of cottonseeds. In laying hens, gossypol reduces feed intake and efficiency and leads to decreased egg production and weight gain. Gossypol also adversely affects interior egg quality, leading to yolk discoloration (olive color). Although low-gossypol cottonseed meals mitigate these effects, the CPFAs in cottonseed oil result in yolk mottling and pink albumen. So cottonseed meal should not be fed to hens while laying.
Induced molting of laying hens is a common practice in the commercial egg industry in the United States. Molting rejuvenates the reproductive tract, resulting in improved egg production and egg quality. In the past, typical molting programs involved reduced hours of light exposure for the hens and the removal of feed until the hens lost 25% to 30% of their body weight. Investigations into alternatives to complete feed removal have revealed that cottonseed could have a role in the induction of molt in laying hens. While cottonseed should not be fed to hens in egg production, diets with 50% ground cottonseed have been shown to be equally effective in inducing a molt as complete feed withdrawal.
If supplemented with sufficient lysine, good quality cottonseed meal can be substituted for soybean meal in growing diets after turkeys reach eight weeks of age.