Puunjalostusteollisuuden jäteliemipulveri märehtijäin rehuna

Authors

• Maija-Liisa Salo Yliopiston kotieläintieteen laitos, Helsinki
• Matti Immonen Yliopiston kotieläintieteen laitos, Helsinki
• Kaija Suomi Yliopiston kotieläintieteen laitos, Helsinki

DOI: https://doi.org/10.23986/afsci.72948

Abstract

The nutritive value of dried ammonium spent sulphite waste liquor was investigated. The waste liquor was a by-product of the birch wood manufacturing industry and was composed mainly of xylane and lignin. These substances largely occurred in such a form that the usual determinations revealed only a part of them. The nitrogen, sulphur and acetic acid contents in the different preparations were 4–7 %, 4.5–9 % and 0.5–7 %, respectively. Digestibility experiments with sheep indicated that when the milk powder in a barley-straw-milk powder diet was replaced with the waste liquor amounting to 18 % (level 1) and 9 % (level 2) of the diet, the digestibility of the organic matter decreased from 84.0 % to 73.5 % at level 1 (P<0.001) and from 82.1 % to 77.8 % at level 2 (P<0.001). The waste liquor diminished particularly the digestibility of the cell-wall substances. Thus the digestibility of crude fibre decreased from 46.3 % to 15.8 % at level 1 and from 37.8 to 29.4 % at level 2 (P<0.001). The waste liquor itself did not contain any cellulose and hardly any crude fibre. The digestibility of the waste liquor obtained by difference calculations was 36.6 % at level 1 and 50.6 % at level 2. The feed unit values were 0.40 and 0.56, respectively (1 fu = 0,7 starch units). The utilization of nitrogen was good and the mineral balances were normal. The palatability of the waste liquor was poor. The upper limit for acceptance by dairy cows was 7–8 % of the concentrate, and even this concentration required a long transition period. It had no influence on the fat content of milk and the haematological values of the animals. Nor did it decrease the milk production if the concentration was so low that the feed intake remained adequate. No noteworthy differences in the palatability were observed between various sulphite waste liquor products, the least palatable was that with the highest content of nitrogen and sulphur.