Reducing greenhouse gas emissions

Published 28 June 10

Below are some ideas from DairyCo about how to reduce the environmental impact of your farm and most will save you money too.


Installing a heat recovery unit (HRU) can help reduce water heating costs by up to 80% by maximising the energy efficiency of milk cooling and water heating.

An HRU is connected into the refrigeration system of the bulk tank, it takes the waste heat and uses it to pre-heat water before it enters the water heater.

You can calculate your water heating and milk cooling costs using the DairyCo Energy Calculator on the website at

A HRU can cost between £1,500 and £3,000 but there is a new interest free loan available from The Carbon Trust to help farmers who want to invest in energy efficiency. For more information visit the website at

For more information order a copy of Energy Efficiency on Farm by calling DairyCo publications on 02476 478702.

Water Usage

You can save thousands of pounds a year while reducing your impact on the environment through more efficient water use on farm.

Mains water supply typically costs £31/cow each year and that can rise to £100/cow on some units. Charges for the disposal of water, in the form of dirty water and slurry, are similarly expensive.

There are some simple things you can do to reduce water usage and wastage on farm:

  • Check regularly for leaks;
  • Harvest rainwater - this provides a free source of water and reduces the cost of water disposal;
  • Recycle water from the plate cooler, it can be used for washing down or drinking water.

For more tips order a copy of Effective Use of Water on Dairy Farms by calling 02476 478702, or download a copy from 

Slurry Injection

The dairy sector accounts for about a third of ammonia emissions from agriculture. Apart from the environmental impact this represents a massive loss of valuable nitrogen.

Consider using a low trajectory slurry application machine to reduce emissions and improve crop utalisation and growth.

  • Trailing shoe or band spreaders can reduce ammonia emissions by up to 60% compared with surface broadcast application, leaving more nutrients available to growing crops.
  • Shallow injection of slurry cuts losses by 70%, while immediately incorporating slurry or manure by ploughing will lower emissions by up to 90%.

Where soils are stony, trailing shoes may be more suitable than injectors, as may be the case if soils are very hard and dry in summer months. To work most effectively, slurry applied with a trailing shoe requires a few inches of grass growth to reduce emissions.

Injection of 33m3/ha 3000gl/acre following first cut silage can save £20 of N/ha compared with surface applications and there are also significant economic gains to be made from maintaining clean swards by using such techniques.

Grass contaminated with surface applied slurry can easily reduce grazing intakes and can significantly affect silage fermentation; reducing quality and intake potential.

Organic producers and those using legumes in their leys must plan their nutrient applications carefully, to avoid over-fertilising clover pastures.


For more information order the DairyCo Greenhouse Gas Factsheet 5, Efficient Milk Production - What you can do about ammonia emissions, by calling 02476 478702 or download it from

Feed Efficiency

Improving feed efficiency by maximising every litre of milk produced per kg of dry matter not only makes financial sense but also reduces your carbon footprint.

Make sure you are feeding to the cows' stage of lactation. Splitting the herd into feeding groups and using in- or out-of-parlour feeders will help to ensure that an individual cow's nutritional needs are met.

Monitoring the performance of the ration - or rather the herd - is another way to ensure that feed efficiency is being maximised.

  • Using a Penn State separator and regularly analysing forages should be part of that monitoring as silage varies throughout the clamp.
  • Even more important is monitoring the cows - both in terms of their milk output, body condition score, health and fertility. They're the first indicator that the ration you have on paper and the one you put in front of them are one and the same.
  • An average FCE is 1.2kg of milk per kg of dry matter consumed; between 1.6 and 1.8 is very good.

It's worth monitoring this figure as just a 0.1 increase can make a big difference to the milk cheque and your margins. For a dairy herd averaging 8,000 litres, an FCE increase from 1.2 to 1.3 will increase milk production by 8.5% with no extra feed costs - just less waste.

Other factors that can limit the efficiency of a perfectly good ration include:

  • Insufficient feed barrier space - the recommendation is to allow at least 0.75m per cow.
  • Neck rails should also be checked for cow comfort and there should be plenty of space in the feed passage for cows to pass behind other feeding cows.
  • Lying space is crucial too, since this encourages blood flow to the udder. Cows should be lying down for between 14 and 16 hours a day.
  • Studies have shown that cows produce a litre of milk for every hour they're lying down. So if your herd only rests for nine hours, that's a potential loss of about five litres per day - that's a lot of milk even for smaller herds.

As part of the industry's commitment to reduce its carbon footprint, DairyCo has produced a series of factsheets and case studies to highlight areas where farmers can make cost savings and reduce their emissions. For more information call 02476 478702 or visit