Neem tree foliage as a substitute for Rhodes grass hay: effects on ruminal fermentation, intake, and digestibility in...

The use of tree and shrub foliage has gained increasing attention as a sustainable feeding strategy for ruminants in arid regions. This study evaluated the effects of progressively replacing Rhodes grass hay (RGH) with partially dehydrated fresh neem tree foliage (NTF) on in vitro ruminal fermentation and in vivo dry matter (DM) intake, nutrient digestibility, and blood biochemical parameters in dry cows. Four diets were formulated in which RGH replaced NTF at 0%, 33%, 66%, and 100% of the forage component. In vitro, increasing NTF inclusion resulted in linear increases in total volatile fatty acid concentration (P = 0.039), propionate (P = 0.028), gas production (P = 0.021), CO₂ production (P = 0.039), and truly degraded organic matter (P = 0.043), while acetate-to-propionate ratio (P = 0.021), and methane (CH₄) production decreased linearly (P = 0.048). In vivo, DM, OM, CP, and NDF intakes and apparent digestibility increased quadratically (P < 0.01), peaking at intermediate inclusion levels (up to 66%) in cows diet. In addition, increasing NTF inclusion linearly increased red blood cell count (P = 0.014), hemoglobin concentration (P = 0.024), and serum glucose levels (P = 0.023). In conclusion, partial replacement of RGH with NTF (up to 66% of forage DM) reduced ruminal CH₄ production and improved fermentation characteristics under in vitro conditions. Moreover, it improved feed dry matter intake and nutrient digestibility without adversely affecting cow health, highlighting the potential of NTF as a promising forage resource for dry cows feeding in arid regions.