Animal feed resources information system

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Wood sugar and wood molasses

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).


Click on the "Nutritional aspects" tab for recommendations for ruminants, pigs, poultry, rabbits, horses, fish and crustaceans
Common names 

Wood sugar, wood molasses

Related feed(s) 

Wood molasses result from a process that transforms the wood cellulose into sugars.


Processes for converting wood into molasses have been known for more than a century.

To change cellulose into glucose, high temperatures and pressures are required when dilute acids are used. With concentrated acids the process can be carried out at room temperature, but the percentage of unrecovered acid makes the cost very high. Hemicellulose is more easily converted into sugars. The hemicellulose from hardwood (e.g., maple and beech) yields a high percentage of 5-carbon sugars, while hemicellulose from softwood (e.g., pine and fir) yields a fifty-fifty mixture of 5-carbon sugars and 6-carbon sugars. Ruminants can assimilate both types of sugars, whereas the 5-carbon sugars are less available to monogastric animals.

The Madison wood-sugar process, which consists in hydrolysing cellulose into simple sugars, is one of the more economical of the many methods developed for this purpose. It involves continuous pumping of a spray of hot 0.5-0.6% sulphuric acid on chips or sawdust heated in a digester to 150 C at the start and gradually increased to 185 C. After removal from the digester the sugar solution is cooled to 138 C and neutralized with lime. The resulting sugar solution contains 5-6% simple sugars and is concentrated to a syrup for feeding. One ton of wood will yield about 0.5 ton of sugars.

A newer related procedure is the solubilization of hemicellulose from wood by steam during the manufacture of hardboard. This process is economical as it does not require chemicals. The hemicellulose sugars are concentrated or spray-dried and sold as animal feed under the name wood molasses.

Nutritional aspects

The syrup has a bitter taste, but this does not seem to make the molasses less palatable to cattle. The syrup can be used for cattle in the same way as sugar-cane molasses.

It can be included up to 5% in pig diets. Higher levels cause digestive disorders.
It can be included up to 5% in poultry diets. Above that level the energy value of wood molasses declines as the amount in the diet is increased. High levels of wood molasses cause digestive disorders.
Sugars from softwood can constitute up to 20% of poultry rations in substitution for the same percentage of grain.
Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 84.4 1
Crude protein % DM 0.4 1
Crude fibre % DM 0.1 1
Ether extract % DM 0.1 1
Ash % DM 7.6 1
Gross energy MJ/kg DM 16.0 *
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 1.7 1
Phosphorus g/kg DM 0.2 1

The asterisk * indicates that the average value was obtained by an equation.


Rubach, 1968

Last updated on 24/10/2012 00:45:24

Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. https://feedipedia.org/node/62 Last updated on June 30, 2010, 0:54

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