Requirements and nutritional balance of phosphorus and crude protein in plants preferred by bighorn sheep (Ovis canadensis mexicana)

The objective was to analyze the content and nutritional value of phosphorus and crude protein diet of the bighorn sheep during the fall at the ‘Unidad de Manejo para la Conservación de la Vida Silvestre’ (UMA) Rancho Noche Buena, Sonora, Mexico. During the fall of 2018 and 2019, 37 species of plants that make up the diet of the bighorn sheep were collected. We estimated the contents of phosphorus and crude protein in plants. In addition, the nutritional balance for phosphorus and crude protein for the bighorn sheep were estimated considering as references the consumption and requirements of phosphorus and crude protein of domestic sheep. Trees and shrubs had the highest content of phosphorus and crude protein. The contribution of phosphorus was 1.39 g·kg-1, while that of protein was 125 g·kg-1 in 2018, and 93.9 g·kg-1 in 2019. Species with the highest phosphorus and protein content in the diet were Acacia willardiana, Mascagnia macroptera, Hibiscus denudatus and Simmondsia chinensis. The phosphorus balance was negative for all physiological stages in sheep, while the protein balance was negative for growing lambs in both years and for lambs in early lactation in 2019. The nutritional balance showed deficiencies of phosphorus and crude protein in the diet of the bighorn sheep during the fall season in Sonora, Mexico.