Nutritional Value of Climate-Resilient Forage Species Sustaining Peri-Urban Dairy Cow Production in the Coastal Grasslands of Benin (West Africa)

SIMPLE SUMMARY: Climate change has increased the frequency of drought along the coastal zone of West Africa, resulting in fodder shortage during the dry season. As forage cropping and conservation are not practiced in this area, animals rely on forage species remaining during the dry season. We assess the vegetation to characterize the range of forage species available for ruminants during the dry season in this region. Among the thirty-three plants consumed by the cows, only thirteen species were available and highly consumed during the dry season. Results showed that most of the forage tested, particularly Poaceae, were of poor in nutritional value; however, the cultivation of some promising drought-tolerant plants such as Dactyloctenium aegyptium, Zornia latifolia, and Chamaecrista rotundifolia could sustain ruminant production along the coastal areas. ABSTRACT: Along the coast of West Africa, grazing ruminants rely on perennial forage species remaining in uncultivated plots, roadsides, and marshlands during the dry season. To assess the quality of these forages, thirteen drought-tolerant plants were harvested at the mature stage, and the samples were evaluated for chemical composition, in vitro fermentation characteristics, and metabolizable energy (ME) content. They are ten drought-tolerant grasses, including: Andropogon virginicus, Brachiaria deflexa, Cenchorus biflorus, Dactyloctenium aegyptium, Eragrostis tremula, Leptochloa caerulescens, Loudetia aroundinacea, Paspalum notatum, Paspalum vaginatum, Pennisetum purpureum, two perennial herbs, Chamaecrista rotundifolia, Zornia latifolia, and one multipurpose tree, Elaeis guineensis. Legume species had the highest nutritional value (highest crude protein and ME, and lowest neutral detergent fiber) of the species studied. In terms of the in vitro data, the gas produced after 120 h of incubation ranged from 149 mL/g in E. tremula to 185 mL/g in Paspalum. Z. latifoliaa and had the fastest rate of fermentation, producing half of the total gas in 19.5 h, whereas E. tremula required 49.9 h (p < 0.01). The production of branched-chain fatty acids (isobutyrate and isovalerate) was greatest for E. guineensis and the lowest in both Paspalum species (p < 0.01). The study suggests the need for the protein supplementation of the animals to ensure maximum forage utilization and to satisfy the nutrient requirements of ruminant livestock.