Description and recommendations
Molasses, sugarcane molasses, A molasses, B molasses, C molasses, syrup-off, integral molasses, unclarified molasses, high-test molasses
Sugarcane molasses is a viscous, dark and sugar-rich byproduct of sugar extraction from the sugarcane (Saccharum officinarum L.). It is a major feed ingredient, used as an energy source and as a binder in compound feeds.
Process and products
Cane sugar is obtained by the way of successive evaporations/cristallization/centrifugation. Both the sugar extraction process and the sugar refining process yield molasses, and each step of those processes ouput specific types of molasses. Pérez, 1995 has described the different molasses as follows:
- Integral high-test molasses is produced from unclarified sugarcane juice. Because it is concentrated from unclarified sugarcane juice, heavy incrustations and scum deposits lead to frequent mill interruptions and therefore to increased factory maintenance costs.
- High-test molasses is basically the same as integral high-test molasses. Howere it does not raise manufactory concern as integral high-test does.
- A molasses (first molasses) is an intermediate byproduct resulting from first sugar crystal extraction (A sugar) at raw sugar factory. A molasses contains 80-85% DM. If it has to be stored, it should be inverted in order to prevent crystallization.
- B molasses (second molasses). It has approximately the same DM content as A molasses but contains less sugar and does not crystallize spontaneously.
- C molasses (final molasses, blackstrap molasses, treacle) is the end product at raw sugar factory level. It still contains considerable amounts of sucrose (approximately 32 to 42%). C molasses does not crystallize and can be found in liquid or dried form as a commercial feed ingredient.
- Syrup-off (liquor-off, jett) is the end product from the centrifugation of the final refined masecuite in a raw sugar refinery. Normally, syrup-off is sent to the raw sugar section of the refinery where it is reprocessed in order to recover more sucrose. Due to its high content of sucrose (90-92% DM), it is an excellent energy source for monogastrics but can be an expensive.
- Refinery final molasses is the byproduct of refined sugar extraction. It has a very similar composition to that of C molasses produced in a raw sugar factory and it is stored in the same tanks.
- In some countries the juice is extracted in a simple animal or mechanical driven press, then boiled in open vats. In this rudimentary process, pan (uncrystallized) sugar is produced and the byproduct molasses is called "melote". It contains only 50% DM.
Sugarcane molasses are also used for alcohol (rhum or fuel ethanol) production and the distillery process yields vinasses that can also be used in animal feeding.
Approximately 3 to 7 tons of molasses can be produced from 100 tons of fresh sugar cane (Pérez, 1997). Molasses composition varies highly and depends on cane varieties, climate and processes (Pérez, 1995). Approximately 60 countries produce sucrose from sugarcane (Pérez, 1995).
It should be noted that the type of molasses is rarely mentioned when molasses are traded or when their feed value is investigated.
Sugarcane molasses has several important roles in livestock feeding, due to the nutritive, appetizing and physical properties of its sugar content. Molasses is rather difficult to handle because of its viscosity: it is rarely fed directly in its liquid form but instead mixed to other ingredients (Caldwell, 2001).
Binding agent, anti-dust agent and palatability enhancer
The main use of cane molasses is as a binding agent in feed mills. Molasses allows the feed granules to stick together during the pelleting process and produce pellets that are less likely to break down during transportation and passage through feeding equipment (Blair, 2007). Molasses also reduces dustiness in fine-particled feeds. Due to its sucrose content, it improves the palatability of feeds and can even mask the bitter taste of urea (Blair, 2007). The amount used in dry feeds is usually small, lower than 15% DM and usually in the 2-5% range (Blair, 2007; Fuller, 2004).
Molasses is a valuable additive for silage making when ensiling conditions are difficult or when the forage is a poor quality grass (warm-season grass) or a legume. Molasses provides readily fermentescible energy that promotes lactic acid bacteria development and subsequently reduces pH and improve silage quality. However, molasses may not be helpful when silage is made with maize, sorghum or cool-season grasses since they already contain high amounts of energy and adding molasses might result in detrimental yeast development (Adesogan et al., 2010; Sansoucy, 1991). Molasses can be added to grass at about 5% (Fuller, 2004).
Molasses, in either liquid or solid form, is often used as a carrier for urea and other additives (Pérez, 1995). Its can be combined with urea, minerals and vitamins to make solids bricks called molasses-urea blocks or multi-nutrient blocks, for inistance to supplement low quality diets (see the Molasses/urea blocks datasheet) (Forsberg et al., 2002).
Molasses can be used as an energy source for livestock, particularly in situations where grains are unavailable or too expensive (Chaudhary et al., 2001). This utilization is common for ruminants, but also occurs in pigs and poultry. Certain countries, like Cuba, have developed feeding systems where molasses has a central part. In ruminants, molasses is fed as a supplement to poor quality roughage, during droughts for instance. It can also be mixed with rice bran, oil meals or with non-protein N (urea for instance) in order to enhance rumen activity (Chaudhary et al., 2001; Bedingar et al., 1990; Rana et al., 1982). During the 1983-1985 famine in Ethiopia, molasses was been used as an emergency feed for the survival of reeding cattle (Menbere, 1986).
In the tropics, molasses is also used in combination with other ingredients, such as roughages, poultry litter or animal by-products. For instance, fresh fish, fish offal and snails can be preserved by mixing 50:50 with final molasses, then fed with B molasses to pigs, ducks and geese (Pérez, 1995).
The world production of sugarcane and beet molasses was 60 million t in 2007 (FAO statistics do not differentiate between both origins). The main producers were Brazil, India, China, Thailand, United States, Pakistan, Mexico, Indonesia, Australia and Russian Federation (FAO, 2011). 15 of those producers were located in tropical areas and accounted for 44 million t which can be assumed to be sugarcane molasses. In 2007, 15.9 million t molasses (from sugar cane and sugar beet) were used to feed livestock. The main users were the United States (1.9 million t), China (1.8 million t), Brazil (1.3 million t), Indonesia, Argentina, India, Mexico, Vietnam, Australia and Iran (FAO, 2011).
Molasses fed in large amounts is toxic to livestock (Pérez, 1995; Dunlop et al., 1979). The symptoms of molasses toxicity are reduced body temperatures, weakness (animals have difficulty standing up), rapid breathing and even blindness (Pérez, 1995; Preston, 1986). Molasses seems to cause brain damage when fed at high levels and with low roughage inclusion. These damages might be due to a lack of thiamine, protein and energy available at the brain level (Preston, 1986; Rowe et al., 1977). However, providing thiamine proved to be ineffective in animals which were suffering from molasses toxicity (Blair, 2011). An economical remedy is to provide adequate quantity of high protein content roughage (such as leucaena or gliricidia) (Preston, 1986). Another remedy is to immediately give animals a solution that is rich in phosphorus and sodium, and to take the animals off molasses feeding for a few days (Pérez, 1995). Molasses toxicity can be caused by a scarcity of drinking water or a too rapid switch-over to high molasses diet, so a close access to water and progressive adapation are necessary (Pérez, 1995).
In high molasses diets with cows grazing succulent pastures, scouring and bloating may occur (Ashwood, 2008). Rumen parakeratosis may also occur in animals fed high levels of molasses (Pate, 1983). Caution must be taken when the spring rains begin; if the molasses is diluted it will rapidly ferment into alcohol and may fatally poison the cattle (Pérez, 1995).
Potassium excess due to molasses can result in nephritis and diarrhoea (Leclerc, 2003).
Molasses usually fed to animals is a liquid viscous product containing 70-75% DM. From a nutritional point of view, it is primarily a source of energy, due to its high sugar content (60-70% DM). Syrup-off contains up to 90-92% DM sugar (Pérez, 1995). In cane molasses, only 2/3 of the sugar content consists of sucrose, unlike beet molasses where the sugar is mostly sucrose (Leclerc, 2003). Molasses is free of fat and fibre with a low nitrogen content. The crude protein equivalent is about 6%, half of which being in non-protein form (Pérez, 1997; Le Dividich et al., 1978). The proportion of non-sugar fraction increases from A to C molasses (Pérez, 1995). Sugarcane molasses is a rich source of minerals. the calcium content is quite high (about 0.9 % DM) due to the addition of calcium hydroxide during processing (Blair, 2007). Cane molasses is also high in sodium, potassium and magnesium, and contains significant quantities of copper, zinc, iron and manganese. However, it is poor in phosphorus (< 0.1% DM) and supplementation may be required. Molasses can be a good source of vitamins such as pantothenic acid, choline and niacin (Blair, 2007). The non-sugar fraction also contains soluble gums, organic acids (citric, malic) and unidentified compounds originating from different chemicals (electrolytes, formaldehyde, sulphur dioxide, hypochlorides, sodium bisulphie and also tensio-active compounds) added during the process of sugar extraction (Leclerc, 2003; Ly, 1989).
Sugarcane molasses is used extensively in ruminants, both as a binder for compound feeds or to supply additional energy to the diet (Pate et al., 1989). It is usually mixed to the feed, but it may be sprayed on low quality roughage to improve its palatability and increase intake (Leclerc, 2003).
When used as an energy feed, for instance to replace grain, moderate amounts (10-20% of diet DM) of molasses are usually recommended. Variable animal responses have been observed at these levels, depending on the relative proportions of the other diet ingredients (forage: concentrate ratio, starch content...). For instance, in temperate areas, 10% molasses is recommended for animals fed energy-rich diets, but it is possible to include up to 15% molasses if the diet contains straw or hay (Leclerc, 2003). The following inclusion rates have been proposed in Western Europe (Leclerc, 2003):
|Dairy cows||2-3 kg/d|
|Steers, heifers||0.25-0.5 kg/d for animals up to 200 kg LW ; 1-2 kg/d for animals over 200 kg|
Many studies showed equal or greater animal performance when molasses was substituted for maize grain (Morales et al., 1989). When molasses account for less than 20% of the total DM intake, their carbohydrates tend to be complementary rather than competitive with the others ingredients of the diets (Preston, 1986). Low amounts of molasses in a roughage-based diet stimulate rumen fermentation and the rumen cellulolytic potential is maintained or improved with low quality forage diets. For instance, an early study in Australia with Friesian and Jersey cows grazing irrigated and N-fertilized pangola grass (Digitaria eriantha) found that supplementation with molasses/urea raised milk yield by an average of 0.67 kg milk/kg molasses with Friesians and 0.39 kg milk/kg molasses with Jerseys. Molasses supplementation generally increased lactation length and the percentage of non-fat solids in milk (Chopping et al., 1976). In a study with growing tropical bulls fed rice straw, the best growth (982 g/d vs 682 g/d) was obtained with 15% molasses (with urea). 10% molasses improved the daily gain of animals fed rice straw and a grass-legume mixture (Huque et al., 1995). When fed alone to cattle or mixed with only 3% of urea, the palatability of molasses is not affected and therefore it should be restricted to 2-3 kg/d. If used as a carrier for higher concentrations of urea, the bitterness of the urea serves as an auto-regulator causing the cattle to consume about 1 kg/d (Pérez, 1995).
Higher amounts of molasses (above 20%) in the diet can be detrimental to animal response, particularly in the lactating dairy cow. Rumen turnover increases, possibly due to higher intakes caused by better palatability. Molasses can depress performance in comparison to isoenergetic grain-based concentrates and reduction in milk yield or milk fat yield has been observed in cows fed 15 to 22% (diet DM) molasses (Granzin et al., 2005). In the growing bull study cited above, 30% molasses depressed growth (Huque et al., 1995). Depression in the efficiency of metabolic energy utilisation for net energy has been observed. This has been attributed to modifications in the production of volatile fatty acids in the rumen, resulting in reduced fibre digestion and lower forage intake (Granzin et al., 2005). Competition between the faster-growing amylolytic bacteria in the rumen and cellulolytic microorganisms results in a decrease in the number of cellulolytic microorganisms present, leading to a reduction in fibre digestion (Royes et al., 2001). Inclusion of large amounts of molasses is not always negative: in a study with crossbred steers fed cottonseed meal and hay, including up to 30% molasses (diet DM; 2.8 kg/d DM of molasses) resulted in increased performance (850 g/d vs 540 g/d). However, the daily gains obtained with molasses were lower than those obtained with the same proportion of soybean hulls or maize grain (Royes et al., 2001).
Molasses is deficient in nitrogen and nitrogen supplementation is often required to optimize rumen fermentation and to provide by-pass protein to balance the nutrients available for the animal metabolism. Adding urea to molasses is a common method to improve its nitrogen status (Preston, 1986).
A number of trials have shown that molasses-based liquid supplements containing urea tend to be inferior to supplements providing natural protein. However, in tropical regions, liquid supplements formulated with urea can be less expensive and economically advantageous (Kalmbacher et al., 1995). Urea has to account for 2.5% of the fresh weight of molasses to provide the ratio of fermentable nitrogen to carbohydrates required for the efficient growth of rumen micro-organisms. No toxicity is observed up to 3% of urea in the fresh molasses (Preston, 1986) but 8-10% results in a decrease of the feed intake (Pate et al., 1989). To prevent urea toxicity, the equivalent crude protein from non-protein nitrogen in a molasses-based feed should not exceed 15 % of total crude protein, unless it is a formula that limits intake (Pate et al., 1989).
Nitrogen supplementation is not always required. Feeding molasses to cattle grazing green pasture with a high nitrogen content is beneficial and does not necessitate additional fermentable nitrogen (Preston et al., 1987).
Molasses sulfur content is high and may antagonize liver tissue accumulation of Se in cattle. A daily intake of 2.5 mg of supplemental Se/day from Na selenite or Se-yeast sources would be needed for cattle consuming sugarcane molasses (Arthington, 2008).
As molasses is deficient in phosphorus, it is necessary to add phosphoric acid to the mixture or provide livestock with mineral supplementation (Pérez, 1995).
Molasses are rich in potassium and should not be mixed with other potassium-rich ingredients such as whey (Leclerc, 2003).
Example of utilization in Cuba
A commercial beef fattening system, developed and used in Cuba since the 1970s, is based on free-choice final molasses mixed with 3% of urea, restricted fish meal or another protein source, restricted forage (3% LW) and free-choice mineral mix of 50% dicalcium phosphate and salt. The molasses/urea mixture, which represents some 70% of total diet DM, contains 91% final molasses and 6.5% water. The urea and salt are first dissolved in water before being mixed with the molasses; this mix is top-dressed, once daily, generally with 70 g of bypass-protein (fish meal) per 100 kg LW. In a large, feedlot operation, the daily ration/head is calculated as follows: 90 g mineral mix, 250 g fish meal, 6 kg molasses/urea and 10 kg of forage. The average daily gain ranges between 0.8 and 1 kg/d. However, under average feedlot conditions the gains are between 0.7 and 0.8 kg/d. Although molasses can completely replace cereals in a beef feedlot operation, such is not the case with milk production, particularly with high producing dairy cows. In this case, the molasses/milk system does not perform adequately. It has been postulated that the problem could be one of insufficient glucose precursors related to the digestion of the molasses, particularly since the demand for this nutrient is greater in milk than in beef (Pérez, 1995).
Sugarcane molasses is normally used as a binder but can also partly replace cereal grains in pig diets. The ME content of sugarcane is about 12.5-13.5 MJ/kg DM (Noblet et al., 2002; Figueroa et al., 1990b; Rostagno et al., 2005), which represents 78-84% of the ME of maize expressed on DM basis but only 66-74% of that value when expressed on as fresh basis. It may be negatively affected by the ash content.
Even though molasses is very palatable to pigs, high inclusion rates are not recommended. Not only molasses is difficult to handle and to mix with other ingredients, but it may cause diarrhoea and can be detrimental to performance, including feed conversion ratio, energy digestibility and N retention (Le Dividich et al., 1974). Molasses has been tested in many trials in Latin America and southern Asia. For molasses with high ash content (14% DM), the main limitation is the risk of diarrhoea, which may occur when molasses exceeds 10, 20, and 30% of the diet (as fed basis) for post-weaning, growing and finishing pigs, respectively. Diarrhoea of pigs fed diets high in molasses is reduced or eliminated by adding an adsorbing fibrous material such as bagasse pith or bran to the diet (Brooks et al., 1967). Pregnant sows can tolerate up to 40% molasses with no adverse effect on litter performance (Garg et al., 1983). Due to its laxative effect, molasses can be used at 10 to 20% dietary level to correct problems of constipation in sows at farrowing time (Blair, 2007). In Cuba, gestating sows have been fed B molasses included in three basic fattening rations (all % in diet DM): 1) Treated organic wastes (33), dry ration (33) and B molasses (33); 2) protein supplement (53) and B molasses (47); 3) B molasses (70) and Torula yeast cream (30) (Pérez, 1995).
Trials in Cuba, Santo Domingo, and Mexico have shown that cereal grains can be completely replaced in the diet with high-test molasses (with low ash) without detrimental effect on growth performance in growing and finishing pigs. High-test molasses had a limited laxative effect (Castro et al., 1990, Figueroa et al., 1990a, Mederos et al., 1990, Gonzalez et al., 1993, Diaz et al., 2002).
Molasses is typically used as a binder in dry poultry diets but its use as an energy source has also been investigated. Poultry, particularly geese and ducks, can be fattened on liquid diets containing up to 60% DM of molasses, preferably high-test, A or B molasses (Göhl, 1982). Lower inclusion rates (< 25% DM) seem generally preferable, both for practical and economic reasons (Göhl, 1982; Rosenberg, 1955).
Early research showed that sugarcane molasses could be used up to more than 30% in broiler diets. However, high levels of molasses tend to cause sticky droppings and caked litters (Rosenberg, 1955). Very high inclusion rates, such as 40-60%, may depress performance (Rahim et al., 1999) or cause diarrhoea in broilers (Savon et al., 1983). Feeds including large amounts of molasses should be pelleted and dehydrated, though this may decrease the cost-effectiveness of molasses (Rosenberg, 1955).
In Cuba, several trials have shown that replacing completely maize with high-test molasses in broiler diets between 18 and 42 days could maintain or improve performance (meat yield, organoleptic properties) while increasing cost-effectiveness (Hidalgo et al., 2005; Valdivie et al., 2004). Many trials have tested molasses successfully at moderate inclusion rates. In India, molasses could be added in broiler mash at up to 10% (replacing maize grain) without affecting performance, but adding molasses directly in the drinking water (2-3% v/v) depressed body weight (Reddy et al., 1998). In Egypt, chicks raised on sand or wheat straw and supplemented with 4% molasses gave better performance than chicks reared on wheat straw only (El-Sagheer, 2006). In Nigeria, broilers fed 15% molasses had better performance (growth, final weight, nutrient digestibility) than animals fed lower amounts or no molasses (Njidda et al., 2006). In Sudan, broilers fed 11 and 12% molasses in the starter and finishing rations respectively in substitution for sorghum grain had similar performance than birds fed the control diet. Molasses included at 39 and 42% in the starter and finishing rations significantly decreased feed intake, increased liveweight, feed efficiency and dressed carcass percentage (Rahim et al., 1999).
High levels of molasses have been mentioned for laying hens (Soldevila et al., 1976). In India, laying hens fed 7.5 to 30% molasses (replacing maize grain) gave the highest laying performance (hen-day production, total mass of eggs, cost of feed/12 eggs) at 22.5% dietary levels. Feed efficiency decreased at 30% but was still higher than for the control diet (Sharma et al., 1973). In Bengladesh, molasses could be included up to 5% (replacing wheat grain) in the diet of laying pullets with no effect on growth and laying performance (Rahman et al., 1991).
It was possible to feed 6-week-old goslings for 8 weeks with a diet containing 62% molasses (instead of 77% maize grain) but weight gain and feed efficiency were higher for the maize-based diet (Valdivie et al., 1974).
Sugarcane molasses is one of the most common ingredients of commercial rabbit feeds. It was used for example in 93 out of 95 French commercial feeds studied by Lebas et al., 1984. The incorporation level is generally comprised between 3 and 5%. In the papers presented at 9th World Rabbit Congress (2008), sugarcane molasses were included in 15 of the 58 control diets with an average inclusion rate of 2.8% and a maximum of 5% (Lebas et al., 2009). The main purpose of using sugarcane or beet molasses in commercial rabbit feeds is to improve the pelleting process and the palatability of pellets. However, the presence of molasses in balanced rabbit diets does not have nutritional benefits. For example, in a study carried out in Benin, the incorporation of molasses at 5% in the diet of young growing rabbits did not improve average daily gain, feed conversion ratio, feed intake and mortality rate (Kpodékon et al., 2008). Also, including more than 5-6% molasses in pellets is detrimental to their quality as pellets become too fragile (Thomas et al., 2001).
Several trials have investigated the concept of introducing a high proportion of molasses, from 25 to 50%, in non-pelleted feeds fed to rabbits in the form of blocks of 0.5-1 kg, mixed with 3 to 10% of cement or lime (Dinh Van Binh et al., 1991; Balestra et al., 1992; Amici et al., 1995; Linga et al., 2000; Doan Thi Gang et al., 2006; Mudunuru et al., 2008). Those blocks are well accepted by rabbits if they are not too hard. Nutritional efficiency depends of the other ingredients included in the blocks (cereal grains or their by-products, oil meals, forages…) or fed in the diet, and results show that that high proportions of dietary molasses can be efficiently used by rabbits. However, the high moisture content causes mold problems even for short term storage. Thorough drying requires at least 2 or 3 days in an electric oven (at 60 or 54°C respectively) or 3 to 6 days of sun-drying (Finzi et al., 1996; Linga et al., 2000: Nouel et al., 2003). Crumbles containing a lower proportion of molasses (10-15%) are well accepted by rabbits but drying is also required (Finzi et al., 1996; Linga et al., 2000).
Horses and donkeys
Horses can be fed 1.5-2 kg/d molasses (about 10-15% of the diet DM) (Leclerc, 2003).
Tables of chemical composition and nutritional value
|Dry matter||% as fed||73.0||1.8||67.8||79.0||3254|
|Crude protein||% DM||5.5||1.4||2.1||9.3||1450|
|Crude fibre||% DM||0.1||0.1||0.0||0.3||8|
|Ether extract||% DM||1.0||0.9||0.0||2.5||19|
|Total sugars||% DM||64.1||3.7||54.8||78.6||2327|
|Gross energy||MJ/kg DM||14.7||0.6||14.7||16.5||7||*|
|Aspartic acid||% protein||22.0||1|
|Glutamic acid||% protein||10.0||1|
|Ruminant nutritive values||Unit||Avg||SD||Min||Max||Nb|
|OM digestibility, Ruminant||%||79.7||1|
|Energy digestibility, ruminants||%||76.6||*|
|DE ruminants||MJ/kg DM||11.3||*|
|ME ruminants||MJ/kg DM||9.6||*|
|Nitrogen digestibility, ruminants||%||43.1||*|
|Pig nutritive values||Unit||Avg||SD||Min||Max||Nb|
|Energy digestibility, growing pig||%||90.0||9.6||77.1||96.0||3||*|
|DE growing pig||MJ/kg DM||13.3||2.0||11.4||16.6||5||*|
|MEn growing pig||MJ/kg DM||13.0||*|
|NE growing pig||MJ/kg DM||9.2||*|
|Poultry nutritive values||Unit||Avg||SD||Min||Max||Nb|
|AMEn cockerel||MJ/kg DM||13.0||*|
|Rabbit nutritive values||Unit||Avg||SD||Min||Max||Nb|
|Energy digestibility, rabbit||%||91.6||*|
|DE rabbit||MJ/kg DM||13.5||1|
|MEn rabbit||MJ/kg DM||13.2||*|
|Nitrogen digestibility, rabbit||%||67.9||1|
The asterisk * indicates that the average value was obtained by an equation.
AFZ, 2011; Ahmed et al., 1983; Alvarez, 1977; Bayley et al., 1983; Bredon, 1957; CIRAD, 1991; DePeters et al., 2000; Figueroa et al., 1990; Hindrichsen et al., 2004; Kamra et al., 1989; Kik, 1960; Le Dividich et al., 1974; Maertens et al., 1985; Mee et al., 1979; Nadeem et al., 2005; Noblet et al., 1989; Perez et al., 1970; Reddy, 1997; Shi et al., 1993; Steg et al., 1985; Unsworth et al., 1976
Last updated on 24/10/2012 00:44:36
|Dry matter||% as fed||75.0||1|
|Crude protein||% DM||0.8||1|
|Crude fibre||% DM||0.0||1|
|Ether extract||% DM||0.0||1|
|Gross energy||MJ/kg DM||17.1||*|
|Pig nutritive values||Unit||Avg||SD||Min||Max||Nb|
|Energy digestibility, growing pig||%||90.1||*|
|DE growing pig||MJ/kg DM||15.4||*|
The asterisk * indicates that the average value was obtained by an equation.
Last updated on 24/10/2012 00:45:09