An evaluation of Panicum maximum cv. Gatton: 2. The influence of stage of maturity on diet selection, intake and rumen fermentation in sheep

Abstract

The aim of the study was to evaluate the nutritional value of Panicum maximum cv. Gatton for sheep production in three different seasons and at three different stages of maturity. More mature pasture, compared to younger pasture, resulted in lower quality being selected. This was reflected in lower N values, lower digestibility and higher NDF, ADF and ADL values in selected material. Digestible organic matter intake (DOMI) also decreased with maturity. Grazing of more mature pasture resulted in lower rumen ammonia nitrogen (NH3-N) levels and higher acetic:propionic acid ratios. This trend was noted in all seasons. The nutritional value of the pasture in summer was high enough to meet at least the maintenance requirements of sheep in all stages of maturity evaluated. The nutritional value of the young and medium mature autumn pasture was also high enough to meet at least the maintenance requirements, but at the mature stage intake was too low. Intake in winter at all stages of maturity, was too low to meet the maintenance requirements of sheep.