Benefits and considerations when feeding youngstock molasses

Strategic feeding during identified phases of heifer growth can be useful to get heifers to target weight at breeding and liquid feeds such as molasses can play a role in driving intakes.

Farm-grade molasses products are presently priced at around £180/t fresh weight, which converts to £264/t of dry matter (DM).

We speak to independent nutritionist Tim Davies, of Kite Consulting and Bronwen Pihlwret, nutritional adviser at Quality Liquid Feeds, to get advice on feeding molasses.

See also: 5 key ways to optimise maize feeding

What is the benefit of feeding high-energy liquid feeds?  

High sugar molasses-based liquid feeds can be useful to improve palatability, and to supply the rumen with readily fermentable energy to boost the rumen microflora.

In situations where protein in the basal forage is less than 14%, a high protein liquid feed consisting of molasses and urea can be fed.

This stimulates the rumen microbes to convert the urea nitrogen to high-quality microbial protein and reduce the need for supplementary protein.

What are the key considerations?

It is important to consider the breed, age, target growth rates and forage fed when deciding which supplementary feed to offer. 

For breeds with a daily liveweight gain (DLWG) target of 0.7kg from 12 months of age, 3kg of a 60% DM high-energy liquid feed containing 30% protein would replace about 1.75kg of a 26% protein blend. This might work without the need for additional supplementation, depending on the quality of forage.

For a faster-growing Holstein, which requires a DLWG target of 0.8-0.9kg, extra energy and protein will be required, but the supplement must be guided by the forage analysis.

For instance, in a maize silage or wholecrop-type diet, a mineral containing sufficient calcium should be included in the ration.

This is because maize, wholecrop and straw are all low in calcium – grass silage and hay are better – but it is important to keep an eye on calcium, magnesium, vitamins and trace element levels.

In forages that are low or borderline for calcium you can get either stunted growth, rickets or even spontaneous bone fractures.

In diets which are low or borderline for magnesium, sporadic sudden death is possible, particularly if the grass or silage is high in potassium.

What should you look for in the nutrient values of liquid feeds?

Adequate intakes of carbon sugars such as sucrose found naturally in plants such as grass are needed for heifers to gain the full benefits of feeding molasses, so be guided by the DM and sugar content of feeds.

Syrup-based products, or very low DM blends, for instance, may have lower levels of fermentable sugar. Syrup products are already a byproduct – the starch has been fermented to sugar – so they can’t ferment further in the gut.

Molasses with protein added, mimics conventional proteins when digested in the rumen.

Consider the age of the animal if feeding a liquid product containing feed-grade urea, as urea in any form is not suitable for animals under 16 weeks.

How should it be stored?

Molasses products generally have a three month “best before” shelf life.  An important consideration is if they are mineralised, because the mineral will degrade.

Make sure you store products out of direct sunlight in a suitable bulk storage tank or intermediate bulk container (IBC). 

What feeding options are best?

In free access situations, liquid feed can be dispensed to heifers in a lick tank. In this situation, the only labour requirement is to top up the feed tank. Tanks should never be allowed to run dry to avoid the risk of gorging.

A lower DM product is preferable when using a lick to prevent it sticking to the wheel and encouraging over-consumption.

Where licks are placed is vital:

  • Never position them where animals gather or they become habit forming – an animal must purposely visit the lick rather than use it just because it is in front of them
  • Avoid placing near water troughs
  • When used outside, avoid placing them under trees or on a natural track.

 When fed to heifers as part of a total mixed ration, the labour input is as for the inclusion of any other product in the mix.

What weight gains should you expect?

Growth will depend on the forages and other feeds included, as well as the DM and protein sugar level content of the molasses-type fed.

The aim of the overall diet is 0.8kg a head a day but forage-type quality is a huge influence on the starting point. The objective is to drive intakes of forage and supplement with protein for regular and consistent growth.

How much should be fed per day and how?

This is also linked to other elements of the heifer diet. 

It is not about using sugar as a sticking plaster, you need to know what is in the background forage, so forage analysis is an absolute necessity. If 6% of the overall intake is from fermentable six carbon sugars such as sucrose, there will be improvement in fibre digestibility to drive DM intakes.

Case study: Chris and George James, Stackpole Home Farm, near Pembroke

George James

George James © MAG/Rhian Price

Heifers below target weights at a Pembrokeshire dairy farm are being supplemented with free access molasses and slow release feed grade urea to advance growth. 

Father and son Chris and George James introduced the system to ensure all the spring-born heifers achieve a breeding weight target of 300kg.

Although the majority achieve this on a forage-only system, around 20% might fall short.

 “Our target is to get all heifers at the correct weights at breeding,’’ says George, who rears 360 heifers as replacements for the New Zealand Friesian-cross herd.

At housing, silage is fed in bunkers, but the yard is not designed for feeding concentrates.

The Jameses have now introduced free-wheel lick feeders to supply liquid minerals at housing.

Heifers have been grouped according to weight. This year, 75 that were below 200kg at nine months old have free access to the feeders; the remainder will get silage only.

George says liquid feed is a convenient and efficient means of supplying the heifer rumen with concentrate in liquid form.

The liquid is stored in IBCs and used to fill bulk lick feeders. Although the yard has been badger-proofed, these are raised off the ground to prevent access by wildlife.  

The lick system works better in combination with good-quality silage, he adds, as heifers will take more of the feed when quality is poorer, pushing up costs.

“If there is a dip in silage quality or we are trying to clean up the troughs we notice that we use more liquid minerals.’’

Harper Adams trial shows gains and health benefits

Trials at Harper Adams University have shown the inclusion of molasses in the drinking water of pre-weaned Holstein-Friesian heifers increased daily liveweight gains.

The undergraduate project, led by Dr Emma Bleach, examined the impact on water and concentrate intakes, weight gain and disease incidence in Holstein Friesian calves by adding 0%, 5% and 10% molasses to drinking water.

The calves started the seven-week trial at seven days old.

Those that were offered the higher concentration of molasses achieved an average dlwg of 0.70kg/day compared to 0.64kg in the 5% group and 0.49kg in the group offered no molasses.  

The trial also suggested positive benefits to health. There was less scour and respiratory disease in calves in the trial groups that received molasses compared to those that didn’t.