Molasses supplementation

Molasses is frequently the cheapest energy supplement available for cattle in areas close to sugar mills. Properly mixed with urea, and with or without protein meal, fortified molasses can address protein deficiencies, while also supplying an energy supplement. Molasses-based supplements have a role in keeping weaners moving forward, in spike feeding heifers and breeders, and in certain circumstances finishing steers (production feeding).

Feeding molasses-based supplements like M8U will result in cattle remaining ‘stronger for longer’ during dry times. Attention should be paid to stocking rates and pasture spelling as molasses supplementation can result in more pasture being consumed, potentially leading to reduced ground cover. Molasses-based supplements can be a very useful production tool, but will not replace good herd and land management practices.

At all times, ensure adequate pasture roughage is available to livestock. Proactive management will ensure stock numbers are decreased, or even completely destocked, before livestock run out of roughage.

In the Northern Territory and Western Australia high transport costs of molasses mean that other energy supplements such as locally grown grain may be cheaper. Often production feeding is too expensive to be cost-effective in the remoter areas of Northern Territory and Western Australia. See Costing supplements or talk to your local beef extension officer to help determine what will work for you.

Value of molasses as an energy supplement

Molasses is primarily an energy supplement, but is deficient in protein. Therefore, it is generally not suitable in a long-term, low-level supplement (e.g. like a dry lick) unless used as a carrier or attractant and intake is controlled and kept to a very low level (e.g. roller drums, lick blocks). Because molasses is not a balanced feed, it is usually of little benefit when it is not fortified with urea. When its energy is balanced with key nutrients, including urea, it becomes an excellent supplement for cattle.

  • Molasses is about 25% water (cereal grains are about 10% water).
  • On a wet weight basis, molasses has about two-thirds the energy per kilogram that cereal grains have. Molasses has 8.7 megajoules of metabolizable energy (MJ ME). Different sugar-refining processes may influence quality, i.e. available energy.
  • Molasses is low in nitrogen and high in sulphur. Therefore, a sulphur source should NOT be included in molasses-based supplements.
  • Molasses has high potassium levels and low sodium levels. Generally salt is added.
  • Molasses is also low in phosphorus.

There appears to be much less variation within mobs in intakes of molasses-based supplements than with other energy concentrates such as straight protein meal.

Main ingredients included into molasses-based supplements


Because molasses is deficient in protein it is necessary to add a minimum of 3kg of urea per 100kg of molasses (for the rumen bugs to be able to efficiently utilize the molasses). Use prilled urea, not granulated urea. Prilled urea dissolves about four times as fast as granulated urea in a mechanical mixer; therefore, prilled urea is cheaper to use and safer.

Urea supplies 2.87g of crude protein per gram of urea (46% nitrogen).

Protein meals

Extra protein may be required for extra animal performance. Vegetable protein meals are used for this role. These can be used up to 40% protein. Cottonseed and copra meals are commonly used. The recommendation is to use the cheapest protein meal available.


When required, salt rectifies the low sodium levels in molasses.


Dicalcium phosphate (DCP) and technical grade monoammonium phosphate (MAP) are the most commonly used concentrated phosphorus sources included into molasses-based production supplements.

Rumen modifiers

These include Rumensin® 100 Premix and Bovatec®. Rumensin® 100 Premix (active ingredient monensin) included at 0.5kg/t is the most commonly used. Rumen modifiers increase feed efficiency; that is, cattle get added benefit from the same feed. Directions for use must be strictly adhered to because of potential toxicity of some of these compounds.

The main molasses-based supplements used in north Queensland

Most common molasses supplements

Supplement What classes of cattle
M8U 1,000kg molasses
+ 80kg urea
+ 500g Rumensin 100 Premix
+ phosphorus in phosphorus deficient country
Weaners above 140kg
MUP (a)
U = urea
P = Protein Meal
1,000kg molasses
+ 30kg urea
+ 60 to 100kg protein meal
+ 500g Rumensin 100 Premix
+ phosphorus (c)
Weaners under 140kg (b)
As a fattening mix to all classes of cattle
As a production mix for young cattle
  1. 10% protein meal is recommended for weaners and some fattening mixes.
    6% protein meal is an option in fattening mixes for older cattle.
  2. It is advisable to keep weaners in separate management groups (for example, under 100kg, 100–120kg and 120–140kg).
    Weaners 70–100kg are recommended to also be fed one-third of a kilogram of protein meal per head per day in addition to MUP in a separate trough. Hay should be limited for this class to ensure adequate consumption of the molasses supplement (at least 1kg per day) and the protein meal.
  3. For weaners under 140kg and the fattening mix, also add 10kg DCP or 6.4kg technical grade MAP or Liquifert® P or equivalent per tonne of molasses.


M8U (1,000kg molasses plus 80kg urea) is a common supplement for survival/drought feeding, spike feeding pregnant heifers and cows, and keeping growing steers and heifers growing during the dry season. It is sometimes fed to turnoff cattle for up to three months, late in the dry season to increase turnoff weight or reduce turnoff age. It is an excellent crisis supplement to prevent deaths in all classes of cattle when there is some dry feed available. M8U is also an effective supplement to sustain prepubertal development in many weaner heifers, thereby increasing subsequent reproductive efficiency.

M8U is simply an 8:100 mix by weight of urea:molasses. It is roughly equivalent to a 50kg bag of urea to 100 gallons (630kg) of molasses. Cows will eat 2–3kg/day, weaners may eat less than 1kg/day. Much higher intakes have been recorded at times. Rumen modifiers increase its efficiency.

Molasses with a protein meal

Molasses plus urea plus protein meal can be used in preference to M8U when there is very little dry feed available to cattle. It can stop deaths in crisis situations. Intakes for breeders are usually at least 4–5kg/day and often about 1.5% of body weight. Often a 100:10:3 mix by weight of molasses:protein meal:urea is used. Rumen modifiers increase its efficiency. In crisis situations, cattle may need to be fed roughage as well to meet animal welfare standards.


MUP is used mainly for feeding early weaners which gain weight on intakes of about 1kg/day. In heifers, this supplement sustains prepubertal development (as for M8U). When fed to turnoff cattle late in the dry season (as for M8U), only 3% urea is usually added. MUP is a very effective crisis supplement for all cattle. MUP is molasses + urea + protein meal, the most common ratio by weight being 100:3:10.

Where cracked grain is available cheaper than protein meals, it may be possible to replace all or part of the protein meal with grain. However, stick with protein meal for weaners under 140kg.

Molasses fattening ration

Fattening or production mixes revolve around 3% urea. Usually molasses + urea + protein meal + salt + DCP + rumen modifier in the ratio by weight of 100:3:10:1:1:0.05 (for Rumensin 100 Premix). This can be used to finish cattle on pasture. When offered ad lib., intakes will be about 1.5% of body weight; e.g. 400kg steers may eat 6kg/day; bullocks may eat up to 10kg/day.

Depending on pasture quality, weight gains of up to 0.8kg/day can be achieved; HGPs will increase this rate.

As for MUP, this mix is not suitable as a stand-alone supplement for radical weaners.

Roller drum mix

Usually a mix of molasses + urea + water in the ratio by weight of 4:1:6. The amount of water is varied to regulate urea intake to about 50g urea/day. Used as a long-term, low-level dry season supplement; that is, equivalent to a dry lick as the molasses does not provide significant energy. This is probably the safest method of feeding urea to cattle (good acceptance within the mob). Rarely used now, except in areas where salt cannot be used as a carrier in dry licks. The main problems are capital equipment, distribution of large volumes, and intake control.

Lick blocks

Many blocks incorporate molasses, usually as an attractant.

Feedlot rations

Up to 15% of the ration can be molasses.

Horse supplement

Molasses + protein meal + DCP + salt in the ratio by weight of 100:10:1:1.

Rumensin must not be added as it is toxic to horses.

Horses on poor feed eating about 3kg/day of this supplement will be kept in good working condition.

Unlike in cattle, straight molasses can still be a useful supplement for horses; therefore, protein levels can be lower than indicated above. Horses won’t gorge this like grain supplements, thus eliminating the potential of founder.

Cottonseed meal should not be added at greater than 15% due to potential toxicity. Other protein meals can be added at higher levels.

Targeting the right animals

With all molasses feeding, target animals in which a biological and economic response can be expected:

  • Spike feed only mid-late pregnant heifers and cows, not those which are empty or early-pregnant.
  • Do not start molasses fattening at high intakes when cattle are a long way from marketing.
  • Discontinue feeding where a response is obviously not occurring.

Mixing supplements


It is essential to use a mechanical mixer, if urea is to be added. Hand mixing of urea is not recommended. Mechanical mixers save a lot of time and ensure safe mixing.

If a molasses mixer is not available, it is safer to use a protein meal as the protein source in the molasses supplement.

Always add urea directly and ensure it is dissolved before adding other ingredients. Undissolved urea can feel like small grains of sand in the molasses mix.

If the molasses is thin (fresh and warm), prilled urea should dissolve in less than 20 minutes in a mechanical mixer. It will take longer if the molasses is thicker, that is, older and colder.

Protein meals

Add steadily to avoid lumps, i.e., lumps may coat with molasses and not mix, especially if the protein meal is not fresh. A grill over the inlet can reduce this problem.

Adding protein meals to molasses thickens the mixture considerably, and necessitates reduction gearing on mixing equipment.


Use flossy-fine salt, as coarse salt is very difficult to dissolve.

Intake control

A litre of molasses weighs 1.4kg; compared with a litre of water which weighs 1kg. So, calculate the amount fed/eaten of a mix in kilograms by multiplying the amount fed/eaten in litres by 1.4.

Other handy conversions for molasses are:
4.5L (1 gallon) = 6.3kg
200L (44 gallons) = 280kg
720L (160 gallons) = 1t

When urea is added to molasses at 8% (M8U), there is no need to feed intermittently to control intake (compared with 3% urea), and cattle don’t linger near the feeding area providing there is some paddock feed.

With straight molasses/urea mixes, cattle tend to regulate supplement intake so that urea intake is constant; i.e. the lower the urea concentration, the more they will eat.

Adding protein meals increases palatability and intake. This can be balanced by urea inclusion.

Intake of palatable supplements may be controlled by intermittent feeding, though this can cause management problems.

Molasses is low in sodium and high in potassium. This restricts intake and reduces performance. If salt is added at 1%, intakes and performance may increase substantially, e.g. by 50%.

Rumensin 100 Premix is unpalatable and may reduce supplement intakes; this may only be for a short time if levels up to twice the recommendations are used. Increasing the level of Rumensin (e.g. up to 3.5 times recommendations) must be managed carefully to avoid toxicity.



Urea toxicity is rare when at least 8% urea is dissolved in molasses.

The risk of urea toxicity is reduced if mixes with high levels of urea (e.g M8U) are kept in front of cattle at all times. Intermittent feeding increases the risk of gorging, and therefore toxicity.

Urea toxicity and molasses bloat are less likely if cattle are introduced to 8% urea on Day one, and not to lower levels of urea and graded up. Cattle will often gorge, resulting in deaths, when the level of urea is in the range of 3 to 8% in molasses/urea mixes, particularly when introducing it to hungry cattle (not enough feed to satisfy gut fill).

Rain on well-mixed M8U is almost invariable not toxic. However, if rain does fall on M8U, the water should be bailed off. Do not mix it into M8U as cattle may drink the mix and deaths may occur.

When urea is not dissolved it concentrates in the top. Urea can then concentrate into rain on top of the mix, and be lethal to cattle that drink it.

Urea is not generally toxic to horses at the levels fed to cattle. Therefore, it is safe for horses to eat M8U, though it is not an efficient supplement for them.

At higher levels of urea intake, urea will be toxic to horses. Horses will die just as cattle do from drinking water with medium levels of urea dissolved.


Two syndromes occur, both when there is very little other feed for cattle to eat:

  1. Molasses toxicity
  2. Molasses bloat.

1. Molasses toxicity
The flow rate through the rumen is so slow that Vitamin B is destroyed. So the syndrome is actually a vitamin B deficiency and presents as `molasses drunkenness’; i.e. the animals stagger around blinded. Treatment with either a vitamin B injection or green feed (e.g. lucerne) is usually spectacularly successful. Prevention is simply achieved by adding salt at 1% to the mixture, and providing extra dry matter, even if it is a small amount of low-quality roughage. Both increase the flow rate through the rumen, thereby denying the opportunity for break down of all the vitamin B.

2. Molasses bloat
The rumen blows up with the formation of a foam. Cattle can go down and die from respiratory failure, simply because of the pressure on the lungs. Treatment is the standard for bloat. Prevention is the same as for molasses toxicity, and is very effective. Bloat often occurs when cattle have a rapid intake of a molasses-protein meal mix after a period without feed, e.g. when intakes are being controlled by intermittent feeding.


Monensin is very toxic to horses. If there is any chance that horses may have access to a supplement, Rumensin 100 Premix must not be added.

Monensin can also be lethal to cattle if there is accidental over dose. Great care must be taken when adding rumen modifiers; follow the directions on the label!

Cottonseed meal

Cottonseed contains a compound called gossypol which is toxic to horses (and other simple-stomached animals). However, mixes with up to 12% cottonseed meal are safe. Cattle detoxify gossypol in the rumen.

Molasses feeding


On-farm storage is vital if significant amounts of molasses are fed. Storage requirements depend on availability of molasses from suppliers, and the rate at which it is fed out.

Generally, water tanks are suitable for molasses storage if they are heavy duty or reinforced.

Ensure that there is a very sound base, especially for fibreglass tanks.

Molasses is heavy and very corrosive. In metal tanks it corrodes on the storage line due to condensation and formation of weak acids, so it is best to keep tanks filled, especially outside peak supplementation periods.

Cement tanks corrode and start to leak below the storage line. They are very good if lined with a resistant coating before filling with molasses.

Molasses has a storage life of many years providing it is not contaminated with water. Water contamination leads to rapid fermentation and spoilage.


It is best to set up for gravity filling of storage tanks and gravity emptying into distribution tankers. Big outlets (at least 6″) on storage tanks and on distribution tanks are needed to ensure adequate flow rates. Ensure that the outlet of the distribution tanker is higher than the top of the troughs into which it is being emptied. Develop systems which remove the need to man-handle troughs to be filled; e.g. use a side outlet so the distribution tanker can be driven up beside the trough.

Molasses can be pumped using either a gear pump, or a helical rotor pump; to avoid damage, use pumps that are engineered to do the job. Augers are often used to feed components of molasses-based supplements into mixers. If set up at truck-height level, bulk handling can be more efficient.

Components for molasses supplements are cheaper in bulk (i.e., 0.5 to 1.0 tonne bags), and may be easier to handle with equipment such as augers.

Contract bulk carriers (20–40 tonne semi or B-double loads) are often the most efficient for replenishing stores.

When a lot of supplement is being fed, it is probably best to have a large molasses mixer (e.g. 5 tonnes) mounted on a truck rather than a towed mixer which is generally smaller (e.g. 1.5 tonnes). Molasses mixers mounted on tippers are better as tipping the truck can substantially increase flow rate when the level in the tank is low.


Ideally, there should be sufficient troughs to necessitate feeding only once a week, or as long as it takes for a full tanker load to be eaten, whichever is the shortest period.

Filling is more efficient when fewer troughs are filled from each load.

Provide enough troughs to allow equal access for all in a mob. Troughs should not be too high for the animals, especially calves.

Concrete rings are cheaper than full troughs. Dirt must be packed at the base on the inside to prevent leakage. Large machinery tyres with one side wall out and the bottom rim hole packed can hold up to 300 gallons (1.9 tonnes).

Unless troughs/rings are on concrete or very compacted areas, the dirt around them will be dug out. Therefore, the troughs need to be shifted regularly.


Plan well. Transport, storage, mixing, and feeding can be a logistics nightmare if planning is inadequate. One thousand breeders will eat about 15 tonnes (2,400 gallons) of molasses and 1.2 tonnes of urea each week.


There are substantial capital costs involved in molasses feeding, particularly storage tanks, mechanical mixers, and troughs. The total cost of molasses-based supplements must be calculated delivered to the animal and often is high as for most energy concentrates.

Return on investment can vary from a couple of months to several years. Unless loans are carefully structured, interest rates on the investment are often equivalent to overdraft rates.

As for any significant cost, the risk and financial return on feeding molasses-based supplements should be thoroughly evaluated before purchasing any infrastructure or supplement.

These notes are an introduction to molasses feeding to stock. More detailed information is available from your beef extension officer and in the publications listed below.

Recommended reading

  • Dry season management of a beef business: a guide to planning, managing and supplementary feeding’, Tyler et al. 2008 (PDF 1.11 MB)
  • ‘Bone chewing country – Cattle management for northern Australia’, Boorman, A.J. (1991). Queensland Department of Primary Industries, Brisbane.
  • ‘Production feeding for profit’, Lindsay, J.A. and Laing, A.R. (1994). Advisory Note, Queensland Department of Primary Industries, Swan’s Lagoon Beef Cattle Research Station, Millaroo.
  • ‘Fortified molasses for beef cattle in north Queensland’. Smith, P.C. (1986). Queensland Agricultural Journal 112, 35-40.
  • ‘Drought management handbook for north Queensland’, Thompson, R.J. and Tyler, R. (1993). Queensland Department of Primary Industries, Brisbane.

Alan Laing, formerly Queensland Government.