Nutritional characteristics of browse species from Northeastern Mexico consumed by small ruminants

Abstract

SummaryMany browse plants that grow in northeastern Mexico are consumed by domestic and wild range small ruminants. However, their nutritional value is determined by their chemical composition and digestibility. Chemical composition depends on the nature of the plant, but climatic conditions determine leaf maturity. Thus, studies to estimate the seasonality of the nutrient profiles of forages from shrubs are necessary. This paper has the objective to discuss the nutrient profiles and the organic matter digestion from the forage of 32 browse plants (13 legumes and 19 non legumes), that grow in northeastern México, and which are consumed by range small ruminants. Browses such as Acacia berlandieri (L.) Wild Acacia rigidula Benth., Ziziphus obtusifolia T and G., Desmanthus virgathus L. and Cercidium macrum I.M. Johnst. are the most abundant in the range, and also are the most selected by ruminants. The seasonal crude protein (CP) content in browse species varied within a range of 4.0 to 22.0%. The cell wall (from 24 to 53%) and its components: cellulose (from 5 to 31%) and hemicellulose (from 2 to 28%) also varied, and in most evaluated shrubs were lower than Medicago sativa hay. Seasonal lignin content also varied among plants species (from 1 to 24%; annual mean), and was higher than Medicago sativa hay. Condensed tannins were low and seasonally variable in most plants (from 0 to 23%). In general, during winter OMD (ranging from 30 to 68%) was higher than in other seasons. Lignin and condensed tannins negatively affected OMD (r = -0.40; P<0.01 and r = -0.53; P<0.001, respectively). The most selected shrubs were those with the highest tannin content. All plants were low in P and Na relative to the needs of adult goats, sheep and white-tailed deer. It is concluded that the chemical composition and OMD of browse plants were very similar among seasons. Because of their high CP, low cell wall, high mineral content and OMD in all plants, these could be considered as good protein supplements for range small grazing ruminants. However, they must be supplemented with P and Na throughout the year.