NUTRIENT AND MINERAL PROFILE OF WHITE-TAILED DEER (ODOCOILEUS-VIRGINIANUS, TEXANUS) DIETS IN NORTHEASTERN MEXICO

The study was conducted to estimate and to compare the monthly variati on of nutrient content of diets of deer, During 1989, samples of plant species were collected and pooled, according to the botanical composi tion of feces to simulate the monthly diet of deer. Collections were c arried out in four ranches (about 12 000 ha) located in the state of N uevo Leon. Two diets in each ranch were evaluated for CP, neutral dete rgent fiber (NDF), acid detergent fiber (ADF), insoluble nitrogen in a cid detergent fibre (INADF), in vitro dry matter digestibility (IVDMD) , macro and trace minerals. Deer consumed diets with a high content of browse species (annual mean 94.2%). Forbs represented 5.2% and grasse s 0.6% of the total composition. The crude protein (CP) in diets varie d(P < 0.01) throughout the year (annual mean 15.1%). The IVDMD was low during all months (annual mean 39.9%), High levels of the shrub Acaci a rigidula (about 50.0%) which had high levels of condensed tannins (a bout 15.0%) may negatively influence the in vitro digestion of DM. Cal cium, Mg, Na and K concentrations in deer diets were in adequate amoun ts to satisfy ruminant requirements. Phosphorus levels in diets were e xtremely low during all months. Conversely, higher concentrations of P in feces may indicate that deer had consumed more forbs than those de termined by microhistology in feces. Although deer requirements of tra ce elements are unknown, they selected diets with concentrations of Fe , Mn and Cu to cover beef cattle requirements. However, Zn was the mos t limiting trace element appearing at marginal levels in diets during 6 months (summer and fall). It is recommended to managers and owners t o open forest canopy in the range to allow an increase of forbs and na tive grass diversity and density with its associated increased nutriti onal value.