The nutritional composition and digestion of plants foraged by red deer (Cervus elaphus xanthopygus) in northeast China

We studied species of plants foraged by red deer in the Muling forest region of northeastern China during January 2014 and 2015. We focused on nutritional composition, energy content, and the digestibility of these plants. Crude protein content varied by plant species. Average crude protein content was 7.5 ± 1.7% of dry matter, ranging from 4.5 to 10.3%. Crude lipid content did not vary by species and averaged 7 ± 1.5% (range 5.4–9.8%). Non-fiber carbohydrate (NFC) and neutral detergent fiber (NDF) content varied broadly with average values being 20.1 ± 4.8% (range 13.5–28.8%) and 64.7 ± 5.9% (range 53.5–71.8%), respectively. Energy content ranged from 16.7 to 19.7 kJ/g. Average dry matter digestibility (DMD) was 46.1 ± 4.8%, with a range from 38.7 to 54.6%. Only three plants, Saussurea manshurica, Aralia elata and Equisetum hyemale exhibited DMD > 50%. NFC content explained most of the variation in energy content (r = 0.451). In contrast, energy content was inversely related to NDF (r = −0.443). There was no correlation between crude protein, crude lipid, and energy content (rprotein = 0.004, rlipid = −0.190). S. manshurica, A. elata and E. hyemale had higher NFC and lower NDF content. Thus, these species offered the greatest nutritional value for wintering red deer in the study area. Along with high CP and NFC content, Taxus cuspidate also had high lignin content, and was thus, considered a good forage species for red deer.