The nutritional value of condensed distillers solubles for cattle

Condensed distillers solubles (CDS) is a by-product of bio-ethanol production from grains. Its quality may vary because of the use of different grains and grain fractions and of different production processes. In order to better valorize CDS in cattle nutrition, chemical composition and nutritive value of 5 batches originating from the 3 Belgian plants, 1 Dutch and 1 German plant were evaluated. CDS is a pasty product with a dry matter content varying from 248 to 325 g/kg and a low pH (3.5 – 4.7). Crude protein content was very high for the German CDS (495 g/kg DM) and varied from 238 to 315 g/kg DM for the other products. CDS is also rich in crude fat (61 – 95 g/kg DM) and sugars (97 – 154 g/kg DM). CDS contains little cell-walls (43 – 154 g NDF/kg DM). Crude ash content varied from 41 to 108 g/kg DM. According to the dairy cattle requirements CDS is high in P, K and Na but low in Ca. The organic matter digestibility of CDS fed to sheep in combination with maize silage (in a ratio of 40/60 on DM-basis) was high and varied moderately from 85.3 to 88.9%. From that a net energy value for dairy cattle (NEL) between 7.78 and 8.45 MJ/kg DM was derived. Rumen by-pass protein (%BP) and intestinal protein digestibility (%BPd) of CDS were estimated from in vitro digestibility with protease using regressions based on in situ nylon bag data from a set of 31 protein rich dry by-products. The %BP varied from 30.3 to 41.7% and %BPd from 81.5 to 99.1%. According to the Dutch protein system the content of protein digestible in the intestines (DVE) and the rumen degraded protein balance (OEB) was highest for the German CDS amounting to 235 and 204 g/kg DM, respectively. For the other products, DVE varied from 123 to 168 g/kg DM and OEB from 56 to 110 g/kg DM. It can be concluded that CDS is an energy and protein rich feed, but its nutritional value for cattle may vary considerably.