INFLUENCE DES CULTIVARS ET DES STADES DE CROISSANCE SUR LE RENDEMENT EN MATIERE SECHE ET LA COMPOSITION CHIMIQUE DE FOURRAGES D’AVOINE IMMATURE

Abstract

The forage yields and the detailed chemical composition of six cultivars of oats harvested at the vegetative stage (three cuttings during the growing season to simulate grazing) and at the heading and dough stages (one cutting for silage) were established over a period of 3 yr. No significant difference in the dry matter yields of the cultivars was found within any of the three stages of growth. Highly significant increases in the yields, however, were recorded with advance in maturity from 4210 kg/ha at the vegetative stage to 6754 kg at heading and 9219 kg at dough stage. Likewise, the percent dry matter increased progressively from 12% to 19% to 33% for the same stages. In general, the organic and mineral compositions of the cultivars did not vary significantly within any stage of growth, but were influenced by the age of the tissues. The total digestible nutrient, the crude protein, the cell contents and the mineral elements Ca, P, K, Mg, Na, Zn and Fe decreased while the nitrogen-free extract, the cell walls, the lignin and the hemicellulose increased from the vegetative to the dough stage. The other constituents exhibited a less defined pattern or remained relatively stable from one stage to another.Key words: Yields, chemical composition, stages of growth, cultivars, forage oats