Seasonal production of Andropogen Gayanus: II. Seasonal changes in digestibility and feed intake

Abstract

SUMMARYTwenty-seven sheep feeding trials were carried out on freshly cut Andropogon gayanus, fed daily during three wet seasons, 1966–8.In each year, dry-matter voluntary intake and digestibility were highest during the first part of the growing season and declined with advancing maturity of the herbage. However, at the time of ear emergence in early October, there were small increases in voluntary intake of dry-matter and crude protein digestibility, although further decreases followed after mid-October.Determinations of in vitro digestibility indicated that elongating stems during early October were at least as digestible as leaves.Seasonal changes in crude protein digestibility were much greater than changes in dry-matter digestibility; seasonal changes in feed intake were intermediate. Voluntary feed intake was related to dry-matter digestibility.Voluntary feed intake and digestible crude protein were both closely related to the crude protein content of the forage. It was concluded that crude protein is a useful criterion for predicting nutritive value.