Review: Effect of Processing Whole Cottonseed on Nutrient Digestion, Performance of Lactating Dairy Cows, and Gossypol Bioavailability

Whole cottonseed (WCS) may be processed to reduce ruminal protein degradation and increase the flow of amino acids to the small intestine or to improve the handling characteristics involved with mechanized feed handling systems. Processes that have been studied include delinting, pelleting, roasting, extruding, and coating. The effect of processing on nutrient digestibility and animal performance varies among processing methods. Processing methods such as mechanical delinting and coating with gelatinized corn starch do not appear to alter nutrient digestibility or animal performance, but processing methods such as roasting or extrusion effectively decrease ruminal protein degradation and alter nutrient digestion. The response of lactating dairy cows to roasted or extruded cottonseed varies from trial to trial, but an analysis of data from several trials indicates that the milk yield response to roasted cottonseed in the diet is positive. Processing also affects gossypol form and bioavailability. Processing methods that do not rupture the seed and involve heating appear to increase the bioavailability of gossypol, whereas processes that rupture the seed before or during heating appear to reduce free gossypol concentrations effectively. Additional research is needed to define the effects of processing on nutrient digestion and gossypol form and bioavailability when cottonseed is fed for long periods.