Almost 8 million tons of cottonseeds with a product value of $800 million were produced in the United States in 2005. Most of the cottonseeds are produced in the southern and southeastern United States. Texas, with almost 3 million tons valued at $300 million, leads the nation; and Alabama, with 275,000 tons valued at $25 million, was ranked tenth in cottonseed production in 2005 (USDA-NASS). Table 1 presents the Top 10 states in the nation producing cottonseeds.
|States||Production, 1,000 tons||Price, $/ton||Value, $1,000|
Whole cottonseed, a by-product of the cotton industry, has been used as a supplemental feedstuff for livestock for more than 100 years. Whole cottonseed can be used as a practical source of supplemental protein and energy to reduce the cost of production. One of the major advantages of feeding cottonseed is its reduced cost of handling in areas where it is produced, eliminating the need for processing. One disadvantage of feeding fuzzy cottonseed is that it moves easily through small-diameter auger systems.
“Whole cottonseed” is a term used to describe the fuzzy seed from varieties of cotton plants. Linted cottonseed does not undergo the natural delinting process. Mechanical and acid treatments are the two processes used for delinting cottonseed. The processing of the cotton plant results in a variety of by-products of ginning (gin trash, gin motes, and whole cottonseed), cottonseed processing (delinted cottonseed hulls, cotton linters, and cottonseed meal), and cotton textile milling (cleaning and carding waste, cotton mill sweeps, and cotton mill dust). Easiflo cottonseed processing is a technique in which the fuzzy, whole cottonseed passes through a patented process to glue the lint to the seed for ease of handling and mixing. A 2% gelatinized cornstarch is used to form the crust on the seed. The feeding value of coated cottonseed is similar to fuzzy cottonseed; however, an increase in DM intake has been observed.
Whole cottonseed and other cotton by-products contain gossypol, a yellow polyphenolic compound indigenous to the cotton plant. The concentration of free gossypol in feedstuffs such as whole cottonseed and cottonseed meal varies considerably. The level of gossypol in the seed is about 0.7 to 0.8%; its concentration can be affected by the variety of cotton, soil conditions, levels of fertilizer applied, water supply, and any factor that may affect plant growth.
In nature, gossypol exists in two forms: free and bound. The free form is toxic, and the bound form is considered nontoxic. However, gossypol can be freed in an animal’s digestive tract. Gossypol also exists in two isomers referred to as + and – gossypol. The negative gossypol appears to have more biological activities and is responsible for its toxic effects. The diet of the animal tends to play an important role in the development of toxicity, with high concentrate rations having increased incidents when higher levels of cottonseed are fed. Animals also can tolerate high levels of free gossypol in the seed rather than meal form of cottonseed. Free gossypol in cottonseed will have a slower release compared with the meal.
Nonruminant animals are sensitive to the toxic effects of gossypol, whereas ruminants are somewhat resistant. The signs of toxicosis include labored breathing, decreased growth rate, and anorexia. Long-term feeding of high levels of cottonseed to bulls reduces semen volume and characteristics; however, feeding vitamin E at 4000 IU improves the symptoms. Red blood cell fragility has been used as an early indicator of gossypol toxicity in cattle (Calhoun et al., 1990). Red blood cell fragility occurs when a mature ruminant’s ability to detoxify gossypol has been exceeded.
Recommended levels of cottonseed in the diet of mature cows and weaned calves are 0.5 and 0.33% of body weight. Large breeds of dairy cattle are usually fed 6 pounds of cottonseed, and not more than 8 pounds per day with no signs of toxicity. Feeding 0.5 pounds of cottonseed per day to Angora goats increases red blood cell fragility (Calhoun et al., 1990).
Solaiman, S. G. 2007. Feeding value of whole cottonseed for goats: notes on goats. Technical Paper No. 07-08. Tuskegee University.