Cottonseed Hulls as a Source of Roughage for Animals: An Overview

The aim of the paper is to examine the advantages and disadvantages of incorporating cottonseed hulls into the diets of animals. Cottonseed hulls (CSH) are a byproduct of cottonseed and serve as a valuable roughage source for small ruminants. CSH is rich in fibre, support rumen function, digestion and metabolic efficiency of ruminants. While they are low in crude protein (5.2%) and digestible energy (5.6 MJ/kg), their residual nutrients including essential minerals, fatty acids and bioactive compounds promote growth, reproduction and overall health in animals. The mineral content of CSH including calcium, phosphorus, magnesium and potassium, contributes to stronger bones and efficient metabolic functions. Linoleic acid in CSH aids energy metabolism, immune responses, and reproductive functions. However, CSH has certain limitations, such as high lignin (18%) content, low digestibility (34%) and anti-nutritional factors like gossypol, which affect nutrient absorption. Advancements in processing methods, including pelleting, enzymatic treatments, and degossypolization, have improved nutrient digestibility and nutritive value. CSH can be incorporated in the high concentrate diet of sheep and goats up to 20 to 30% without any adverse effect. Lambs on mesh and pellet CSH at 40% level attain average daily gains of 76 and 88 g respectively. It can be a good source of roughage during scarcity periods for small ruminants to meet their maintenance requirements. In addition to animal feed, CSH has industrial applications in biofuel production, activated carbon manufacturing and organic fertilizers. The high fibre bulk and limited digestibility are some of the research priorities to enhance the economic and nutritional viability of CSH as animal feed.