OBSERVATIONS OF WHITE-TAILED DEER AND CATTLE DIETS IN MEXICO

Most rangelands in northern Nuevo Leon, Mexico, have been grazed inten sely for more than 10 years simultaneously by cattle and white-tailed deer (Odocoileus virginianus texanus). There is a lack of information concerning diet selection of white-tailed deer and cattle in this regi on. We observed the dietary preferences of these ungulates in northeas tern Nuevo Leon for a 6 month period. Two adjacent areas were subjecte d to rotational grazing (RG) and continuous cattle grazing (CG). Fecal analysis was used to determine dietary overlap of these 2 sympatric r uminants, Cattle diets averaged 70% grasses, 23% browse, and 4% forbs, Deer diets were 63% browse, 24% forbs and 12% grasses in both areas. The preferred species for cattle in both areas were grasses, Deer pref erred forbs on the continuous grazed area and grasses on rotational gr azed area Zacate toboso [Hilaria mutica (Buckl.] Benth.) was the most preferred species by both ruminants in both management systems. Differ ences between cattle and deer diets were significant (P < 0.05), The s imilarity index was higher on the rotational grazed (23%) than on the continuous grazed area (15%) (P < 0.05), The higher similarity index i n RG area may have been a result of the altered forage preferences of deer. Zacate toboso under RG could be an important feed resource in th ose areas where white-tailed deer and cattle graze in common.