Feeding Molasses to Cows – Our Guide

Cows eating sugar is not a new or novel concept. If we go back to the origins of cattle feeding, typically fresh grass was the number one feed source.

Fresh grass can easily contain more than 10% sugar on a dry matter basis, suggesting that naturally a cow’s diet should contain high levels of sugar.

Nowadays, a cow’s diet will mainly consist of silage, a preserved form of forage where the preservation has resulted in the transformation of sugar to acids. This creates a shortfall of sugar, with grass silages often containing less than 1%.

This creates a large sugar deficit compared to what would have been available in fresh grass. One of the best and most cost-effective sources of sugar for cattle is molasses.

Molasses can be found in every cow’s diet, not always in the straight form but most pellets or concentrate feed will contain an amount of molasses as it is used as a binder in most feed mills across the country.

However, as a straight feed, feeding molasses to cows can have benefits on increasing dry matter intakes, driving animal performance and health, reducing sorting behaviour and dust levels.

Historically, in years where a lack of forage has been an issue due to poor growing conditions e.g. drought and less palatable feeds need to be fed such as straw, feeding molasses to cows has helped increase intakes and digestibility of these feeds.

Alternatively, the high palatability of molasses has traditionally seen it used as a delivery mechanism when supplementing other unpalatable feed ingredients such as minerals, specifically magnesium.

More recently, investment in research and development has shown molasses to have greater benefits than previously thought, above and beyond the calorie or nutrient value it offers making it a functional ingredient and an essential part of a cattle ration.

The more traditional or historical benefits of feeding molasses include:

• Improve palatability
• Reduce sorting
• Stimulate dry matter intakes
• De-dust rations
• Reduce waste
• Improve coat condition and shine

However, research has shown that feeding molasses to cattle can also:

• Improve fibre digestion
• Balance and optimise carbohydrates in the ration
• Drive rumen function
• Increase microbial protein production
• Increase protein/nitrogen efficiency
• Improve milk yield and quality
• Drive daily liveweight gains

Initial research has focussed on differentiating sugars within molasses and identifying the full composition of molasses to try and determine how it performs as a functional ingredient in a ration.

Researchers have now been able to determine 97.4% of cane molasses composition, allowing us a greater insight into the mechanisms at action.

Firstly, research found that molasses, specifically cane molasses, is naturally high in 6-carbon sugars e.g. glucose and fructose. Most ruminant feedstuffs containing sugar will contain a proportion of 5-carbon and 6-carbon sugars.

5-carbon sugars such as xylose, arabinose and ribose are commonly found in silages and other fermented feeds that have been through some form of processing e.g. pot ale syrup and wheat syrups.

6-carbon sugars have been proven to be more highly rumen fermentable, causing significant increases in rumen microbial activity. This higher level of activity by the rumen microorganisms can help to explain why there are several benefits of feeding molasses to cattle.

Molasses has a high sugar content which has shown to be fully digested and utilised by rumen microbes within two hours of fermentation.

This has led to the belief that high sugar levels in a ration, or specifically high levels of molasses feeding, can lead to an increased risk of sub-acute ruminal acidosis (SARA).

However, several studies has shown this is actually incorrect when it comes to supplying sugar in the form of molasses to the diet. Due to the high content of 6-carbon sugars in molasses, when these are utilised by the rumen microbes, it leads to an increase in butyric acid within the rumen.

Butyric acid is one of the main three volatile fatty acids produced in the rumen, the other two being acetic and propionic acid. Volatile fatty acids are the main energy source for the cow and vital in driving animal performance.

Butyric acid is the least acidic of the main three acids so, by feeding molasses, this has the benefit of not contributing to an increase in acid concentration.

Additionally, butyric acid has a stimulating effect on the rumen epithelium which results in volatile fatty acids being removed from the rumen in a much faster manner.

So, by feeding molasses not only does this favour a less acidic volatile fatty acid but also, the removal of these acids from the rumen happens much faster which actually results in a higher rumen pH and a much more optimum rumen environment when feeding molasses to cattle.

Furthermore, the supply of rapidly fermentable energy in the form of sugars can help optimise the synchrony of energy and protein in the rumen aiding higher levels of microbial protein production.

Microbial protein is the source of protein produced naturally in the rumen, it is the most cost effective and optimal supply of protein to the cow due to its amino acid profile.

When the cow consumes protein, this is broken down into ammonia in the rumen, which can then be utilised by the microbial population. However, the utilisation of ammonia is dependent on the supply of energy, specifically on the rapidly fermentable energy.

Without a supply of instant energy, a lot of ammonia can go to waste in the rumen and end up being metabolised in the kidneys and excreted as urea in urine. By feeding molasses to cattle this helps to synchronise the supply of energy from carbohydrates.

Starches and fibres are slower fermenting than sugar, therefore, sugars can provide that rapidly available energy that the rumen microbes require to kick start fermentation. This helps to drive efficiency and negates any “lag period” in the fermentation of feedstuffs.

By synchronising nutrient supply in the rumen and helping to optimise the rumen environment this makes molasses a good feedstuff for cows.

Many dairy farmers are paid based on not only milk yield, but also the milk fat and protein contents. Many processors pay premiums for higher levels of fat and protein, making it attractive to raise these in a cost-effective way to achieve higher margins on farm.

Around 50% of milk fat is made up of short chain fatty acids which are primarily made up from acetate and butyrate. Research has found that feeding molasses will raise butyrate production in the rumen therefore supporting higher levels of milk fat.

Trial work has shown that using 2kg of a protein molasses based liquid feed in replacement of 1.6kg rape/soya blend increased milk protein by 0.1% and milk fat by 0.15%.

A study carried out by DeVries and Gill in 2012 summarised the benefits of feeding dairy cows molasses, the results of adding 1.2kg molasses to the feed included:

• Dry matter intake increased by 1.4kg/day
• Milk yield increased by 1.9L/day
• Milk fat increased by 0.11%
• 25% reduction in ration sorting

Cost effective beef production is reliant on maximising dry matter intakes and feed efficiency across all feeding stages; rearing, growing and finishing.

Making the most of home-grown forages and cereals can be achieved by ensuring a balanced ration that is not too starch-dense. Starch is a great source of energy however, when fed in high quantities, this can put the rumen environment at risk of acidosis reducing feed efficiency.

By replacing a proportion of starch in the ration with sugar this can overcome the acidosis risk and balance the energy sources for higher feed utilisation and animal health.

Studies have found the addition of up to sugar up to 6-8% of the total dry matter of the diet has several benefits in a beef production system. Research found the main benefits of feeding molasses to beef cattle include:

• Increased daily liveweight gain
• Increased dry matter intakes
• Improved feed conversion ratio
• Increased carcass weight
• Less rumen pH fluctuations
• Less time spent in rumen acidotic conditions
• Optimised rumen environment

The use of molasses in cattle feed is a great source of rapidly fermentable energy which helps optimise the synchrony of nutrients from the whole diet.

Sugars require differentiation to ensure the best results are achieved on farm, not all sugars are equal in their ability to increase dry matter intakes, drive rumen function and maximise feed efficiency.

Feeding molasses to dairy cows and beef cattle can have beneficial effects to both animal and producer achieving cost effective animal production and maximising farm profits. The cheapest ration to feed is not always the most profitable and it is important to look at all aspects of a ration to ensure the best outcome.

If you’d like to know more about how molasses can benefit your cattle or would like support around incorporating molasses into your feed, get in touch.