Intake and digestibility of sunflower (Helianthus annuus)

Abstract

The palatability and nutritive value of fresh sunflower (Helianthus annuus) c.v. Fransol, cut at the flowering stage of growth was determined using eight heifer calves of approximately 200 kg live weight. Intakes were determined over twenty one days and the apparent digestibilities of dry matter, organic matter and nitrogen, using chromic oxide as an indigestible marker were determined during the last nine days of the intake period.

Average daily intake over the twenty one days was 25.0 g/kg W. Intakes of dry matter g/kg W were significantly (10%) higher in week 2 than in week 1. Linear regression equations were obtained of dry matter intakes against live weight and against metabolic live weight.

Digestible organic matter and digestible nitrogen contents of the sunflowers were 596 g/kg and 11.6 g/kg respectively and the metabolisable energy was 9.2 MJ/kg dry matter. Optimum intakes of metabolisable energy of 63.0 MJ/d and of digestible crude protein of 512 g/d by a 220 kg heifer was sufficient to provide energy and protein requirements for a predicted live weight gain of O.89 kg/d. Comparison between predicted L.W.G. on fresh maize showed sunflower to compare favourably with green maize as a complete ration.