Influence of the time of day on nutritive value of elephant grass cv. Cameroon under rotational grazing management by dairy cows

Abstract

The milk production in Brazil has been considerably increasing in the past years. However, production indexes such as milk production per head and animal performance and productivity can still be considered low, when compared to other countries. In Brazil, pastures are a common characteristic to the different dairy systems. Therefore, identification of efficient grazing management practices is essential to increase production indexes, with no consequent increase in production costs. An adequate grazing management practice allows for increase in milk productivity on both animal and land basis, and simultaneously, promotes sustainable development of the dairy systems in the long term, avoiding pasture degradation and mitigating environmental impacts. The balance between plants' photosynthesis and respiration sets the upper limit on non-structural carbohydrates concentration at the end of the day. This limit alters the concentration of other nutritional parameters in the forage available to animals. In rotational grazing systems, with short occupation periods (e.g. 1 day), moving animals to a new paddock at the end of the day might synchronize the start of a meal, with the moment in which forage's nutritive value is highest. The objective of the study is to determine concentration of soluble carbohydrates, starch, NDF, ADF, lignin, crude protein and ether extract in rotationally grazed elephant grass cv. Cameroon in the morning and in the afternoon, by dairy cows. (AU)