Seasonal trends of macro and micro minerals in 10 browse species that grow in northeastern Mexico

Leaves and twigs from shrub species consumed by range goats: Bernardia myricaefolia, Caesalpinia mexicana, Celtis pallida, Diospyros texana, Eysenhardtia polystachya, Gymnosperma glutinosum, Hellieta parvifolia, Parkinsonia aculeata, Pithecellobium ebano and Pithecellobium pallens were evaluated for comparative seasonal contents of Ca, Mg, Na, K, P, Cu, Fe, Mn and Zn. Plants were collected in summer (September 12, 1995), autumn (December 1, 1995), winter (February 22, 1996) and spring (May 31, 1996) in the counties: Linares, Santiago, Iturbide and Montemorelos belonging to the state of Nuevo Leon, Mexico. During summer, mineral concentrations were higher in general. Only Ca, Mg, K, Mn and Fe were in substantial amounts, in all seasons, to meet adult goat requirements. All browse plants had extremely low P and Na contents. Moreover, Cu in all and Zn in most plants resulted with low marginal levels to meet adult goat requirements. However, plants such as B. myricaefolia, D. texana, E. polystachya, G. glutinosum and H. parvifolia can be considered prominent components in diets of range goats because of their high mineral concentrations. It appears that ration formulation for goats should include evaluation of the dominant available plants and consideration of their probable mineral contents during certain seasons for ration formulation.