Morning and afternoon sampling and herbage chemical composition of rotationally stocked elephant grass cv. Napier

摘要

Nutrient intake by grazing animals depends on the amount of dry matter consumed and its chemical composition. Forage grasses, as with any other plants, produce assimilates during the day via photosynthesis to sustain live tissues, plant growth and organic reserves (Taiz and Zeiger 2013). In that context, herbage chemical composition may vary according to variations in the photosynthesis-respiration balance throughout the day. From dawn to dusk the balance increases and herbage dry matter content as well as concentration of soluble carbohydrates increase, the reverse happening from dusk to dawn. That could interfere with nutritive value and nutrient intake of grazing animals (Delagarde 2000), since for a given bite volume the amount of herbage and its composition could vary depending on the time of the day. That could have implications for rotationally managed pastures, indicating a potential effect of time of changing animals from one paddock to the other as a management strategy. Against that background, the objective of this experiment was to evaluate dry matter (DM) content and the concentration of soluble carbohydrates (SC), crude protein (CP), neutral (NDF) and acid (ADF) detergent fibre in herbage samples harvested during the morning and afternoon periods from rotationally stocked elephant grass cv. Napier.