Carbon footprint assessment forces dairy farmer to focus on efficiency

Understanding their farm’s carbon footprint has enabled one Derbyshire dairy to improve production efficiencies that will ultimately benefit the bottom line, as well as the environment, reports Farmers Weekly.

John and Sarah Hotchin admit when they first considered carbon footprinting they thought it would all be about saving fuel and electricity, but instead they have been surprised at the practical management benefits to their business.

The initial assessment

The Hotchins voluntarily undertook their first annual carbon footprint assessment with Alltech EC02 at Hawkslow Farm, in 2011 through their milk processor, Arla. Since then they have made substantial changes to how their 200-cow dairy unit is run.

This has resulted in improved feed efficiencies, lower age at first calving, higher yields and improved fertility, all of which have benefited herd performance.

See also: Arla targets carbon footprint to raise efficiency

At the same time their carbon footprint has dropped from an above average level for Arla farms of 1,711g CO₂e per litre of fat and protein corrected milk (FPCM), to 1,164g CO₂e, which is below average.

The Hotchins farm near Ashbourne on the edge of the Peak District. The Holstein herd calves all year round, is grazed from May to September and yields an average 8,500 litres a cow a year. All heifers are home-bred with the farm growing grass and wholecrop across 350 acres.

Mr Hotchin says overall the business benefits of carrying out the carbon footprint assessment have been marked and has focused their attention on improving cow efficiency.

A closer look at a range of parameters including energy use, cow performance, health and fertility and crop management, showed the farm was making efficient use of electricity.

Their usage stood at 0.047kWh a litre, compared with an average of 0.059kWh a litre. Fertiliser use was also below average and was impacting positively on carbon footprint.

However, the report highlighted a potential opportunity for the farm to reduce its footprint by:

• Reducing age at first calving from 28 months to 24 months.
• Driving down feed emissions through improving feed efficiency further.
• Improving fertility and dropping calving interval from 455 days (see box).

As a result of the report, the Hotchins have implemented a number of key management changes.

1. Reducing age at first calving

Re-evaluating the age at which heifers are put to the bull has been one of the biggest changes for the Hotchins.

Mrs Hotchin explains: “It’s been a big change in mindset. We used to focus on having big, strong heifers and serving at 22 months. Now we’ve reduced this to 18 months and we’re aiming to get this down to 16 months.”

Mrs Hotchin admits an overall reduction in calving age will take time. However since she began serving heifers at a younger age, she has seen no negative impact on their first lactation yields and believes they are also getting back in calf quicker.

“It also means we’re getting something out of them sooner and saving on inputs. We’ve now got less youngstock running around, so they’re making money sooner,” she says.

Following the last assessment in 2014, age at first calving was still around 28 months, however the effects of the Hotchins new attitude to calving age is now coming to fruition with heifers currently calving in at 26 months.

2. Feeding and dry cow management

To get a handle on fertility and help reduce calving interval, the Hotchins have overhauled feeding in both the milking cow and the transition cow group.

Mrs Hotchin explains: “In the past we were getting the yield, but we were struggling to get cows back in calf, which meant we had a long calving interval. Cows used to lose too much condition after calving – once body condition is right, fertility falls into place.”

Now, the milkers are fed for body condition rather than yield. Whereas before they were split into various groups and fed different rations, they are now in just two groups of low and high yielders. They then receive a flat rate TMR and concentrate to yield in the parlour.

To gain greater control of dry cow feeding, all dry cows are now housed. Wholecrop wheat is now partitioned towards the dry cows, instead of the milking cows to provide sufficient energy and scratch factor.

Before, transition cows would have received a proportion of the milking ration. Now one diet is fed throughout the dry period and includes wholecrop, straw, a small amount of silage, molasses, a protein blend, magnesium flakes and minerals. This has meant cows are not getting over fat in the dry period which has benefited health and performance post calving.

“It has meant cows calve better and we have less milk fever and retained cleansing and we have better body condition at calving. Cows also take better to the milking ration straight away after calving so we have reduced DAs,” says Mrs Hotchin.

Feed space has also been improved in the milking shed to stop heifers from being pushed out. This will help maintain intakes and improve yields.

3. Focus on forage quality

The Hotchin’s are now focusing on producing better quality silage, following the planting of new high sugar grass leys.

The fact the Hotchins do their own silage work also means they can cut at the optimum time. Overall this has meant grass silage yields and quality have improved.

4. Tweaks to cow environment and electricity use

As well as carbon footprint, building ventilation has also been improved. This has involved knocking out various panels in the collecting yard and cubicle shed.

A variable speed milk pump has also been installed to save electricity and a heat exchange unit introduced. This helps to heat water for washing down.

Impact on business

Mr Hotchin explains: “Our calving interval has dropped to 405 days. That means cows are in calf quicker and there are more heifer calves on the ground. We’ve got to the point now where we could sell heifers or do more selective culling.”

More heifers calving in has enabled milking cow numbers to be increased from 160 to 190. Fewer heifers on the farm also means the family have been able to keep dairy bred beef calves as stores on rough grazing ground previously taken up by replacements. This provides an added income stream.

As a result of better dry cow management, in the last year average yields have also increased by 1,316 litres a cow a year of FPCM (see table). At the same time, feed rate for every litre produced has also dropped, which Mr Hotchin puts down to better forage quality.

“The higher yields have also helped us cope with the low milk price. We’d be worse off now if we hadn’t seen an increase in milk.”

The future

The most recent 2014 year report shows some improvements in overall carbon footprint at Hawkslow Farm. However moving forward, the Hotchins are planning on making bigger gains in age at first calving by bringing it down to calve at 24-25 months.

A high culling rate of 32% was also identified as a negative influence on carbon footprint. However, this is largely because of more heifers calving in, which has enabled the farm to selectively cull.

TABLE: Changes at Hawkslow Farm
	2011	2012	2013	2014
Grams CO2e per litre (fat and protein corrected milk FPCM)	1,711	1,350	1,401	1,164
Litres of FPCM produced per cow	7,755	8,362	6,519	7,835
Feed rate per litre (kg of concentrate equivalent/litre FPCM)	0.38	0.41	0.45	0.40
% of DMI from forage (cows)	67.5	63.6	63.3	64.8
Cows calving in 365 day period (%)	85	90	83	85
Average age at first calving	–	27	27	28

Example management factors influencing carbon footprint

Age at first calving

• By calving heifers at 24 months, less methane is emitted on farm during rearing when animals are consuming inputs and not producing milk.
• By reducing calving age from 28 months to 24 months, lifetime yield and fertility should be improved and the number of non milk producing animals on farm reduced.
• Calving in younger makes economic sense as on average it costs £2.31 per day per heifer for each day increase in age at first calving.

Purchased feed

• Bought in feed represents one of the biggest costs, both financially and environmentally, to any dairy business.
• Big gains can be made by producing more, quality forage and reducing feed use per litre through careful ration balance.
• Using co-products, such as distiller’s grains can reduce emissions. These are low carbon feeds as they have already been used in one industry to produce another product.

Litres sold

• Increasing overall milk yields will reflect positively on carbon emissions.
• Regardless of yields, a dairy cow will produce an average 100kg methane per year. That means if yields increase, the farm is achieving less methane per litre.

Calving interval

• Achieving a target calving interval of 365 days will maximise litres sold and reduce associated costs from culling and extra veterinary costs, for example.