The nutritive value of South African feeding stuffs. III. Digestible nutrients and metabolizable energy content of a mixture (1:1) of lucerne hay and yellow maize at different planes of intake for sheep

Abstract

Mature Merino sheep were used as experimental subjects in a study of the digestibility of a ration of equal parts by weight of lucerne hay and crushed maize at three levels of nutrition, viz. maintenance, 1 ½ x maintenance and 2 x maintenance. The data yielded the following conclusions: (1) The digestibility of the dry matter was significantly decreased by 2•4 absolute per cent. when the maintenance ration was increased by 50 per cent. Doubling the maintenance allowance had no further influence in this respect. (2) The apparent digestibility of the protein decreased progressively as the plane of nutrition was increased, the decrease over the whole range being 5•2 absolute per cent. This difference was statistically highly significant. (3) The cellulose fraction behaved somewhat like the dry matter whilst "other carbohydrates" (sugars, starch, and hemicelluloses) showed, with increase in plane of nutrition, a progressive decrease in digestibility amounting to 2•9 absolute per cent. at the highest level of intake. This decrease was highly significant statistically. (4) The digestibility of the lignin fluctuated from 4•6 per cent. at the 1 ½ x maintenance level to 13•4 per cent. at the 2 x maintenance level.