Utilization of date palm leaves for livestock feed

Date palm by-products are a variety of products produced during date production and processing. Whereas some of these by-products are classically used as complementary feeds for livestock, others have gained less attention as feed materials. Date palm by-products include wasted dates, stones, floral stems, panicles, and leaves. Wasted dates and stones have high energy content, while stems, panicles, and leaves contain high fiber content. Generally, all the date by-products usually contain 3%–7% crude protein. The by-products are usually offered to animals without any treatment, after soaking in water to improve tenderness or mixed with other feeds such as straw, grasses, or concentrate. Date palm leaves have gained less attention as a feed. Most of the palm leaves are not harnessed beneficially and are thus burned by the farmers, causing great environmental pollution. Date palm leaves have a low nutritive value as a feed for livestock due to their low crude protein and high fiber contents, as well as low nutrient digestibility. Date palm leaves contain about 5%–7% crude protein and high fiber content ranging from 42% to 72%. Combustion, gasification, anaerobic digestion, and composting are the main technologies for biomass conversion of date palm leaves. Treatment with urea and ammonia can overcome the problem of low protein contents in most agriculture by-products. However, due to some concerns about the safety of this strategy, it is not recommended to popular farmers because of the technology and expertise involved. Ensiling of agriculture by-products or crop residues with fibrolytic enzymes, organic acids, lactic acid bacteria, and fungi has gained little attention as strategies to enhance their nutritive value. Ensiling with some additives increased protein contents, decreased fiber contents, enhanced ruminal fermentation, and improved feed digestibility. Physical (e.g., chopping), and chemical (e.g., addition of ammonia or urea-N and ammonium hydroxide) treatments of agriculture by-products or crop residues have gained some interest in ruminant nutrition with a limited enhancement of their nutritive value before feeding.