The Howells family had not set out to reduce their carbon footprint when they introduced strategies to improve herd performance, but those measures have enabled that.

Working with their nutritionist and vet, they have improved the transition management and health of their pedigree-registered Holstein herd and, as a consequence, the farm’s carbon footprint specifically for milk is 0.8kg CO2e per kg of fat and protein corrected milk, compared to the national average of 1.2kg.

Roger and Catherine Howells and their daughter Sarah run the 160-cow Blaengelli herd near Whitland, Carmarthenshire.

Invested

Seven years ago, they invested in new dairy infrastructure to give better control over herd health and production.

While milking cows graze during the day in summer, dry cows are fully housed from drying off.

“We have become more efficient at what we do by taking as much as advice as we can and listening to our vet and nutritionist,” said Mr Howells, who spoke at a recent AHDB-organised event at Blaengelli.

Dry cow nutrition is a key focus area; high intakes are maintained before and after calving to help cows hold their body condition.

This sets cows up for their next lactation and prevents metabolic disorders. Only one case of milk fever was recorded in 2021 and there were no left displaced abomasums.

Mr Howells said: “Milk fever used to be a major problem, but it is rare for us to get a case now.”

This is contributing to efficiency, as industry figures cost every case of milk fever at £200.

Silage is made in a multi-cut system, with five cuts taken in 2022. The crop analysed with a crude protein of 14.8% and a metabolisable energy (ME) value of 10.97MJ/kg of dry matter (DM).

Mrs Howells said: “By improving silage quality, we are getting more milk from the same amount of feed and that means less bought-in feed.”

Yield

The herd is producing an annual milk yield average of 11,000 litres per cow at 4.23% butterfat and 3.5% protein from a concentrate input of two tonnes.

The transition diet, formulated by Ken March, of Perfekt Cow, is made up of grass silage, wheat straw and minerals. This provides 14.34kg DM intake and analyses at 64% DM and 14.87% crude protein, supplying 119MJ ME.

Speaking at the AHDB event, Mr March said dry cow diets should provide adequate fibre and gut fill to reduce the risk of a displaced abomasum occurring after calving.

And by maximising DM intake, freshly calved cows would have a good appetite immediately after calving.

Mr March said: “If you get it right in terms of presentation, a dry cow will eat 12-16kg of DM a day.”

Careful mineral balancing will also control clinical and sub-clinical milk fever, he added.

A constant supply of feed should be available or the cow’s immune system will be compromised, resulting in metabolic disorders post-calving, Mr March said.

“Never allow the feed face or fence to be empty of feed, keep intakes and rumen fill as high as possible.”

He recommended a body condition score of 2.75-3.5 in a dry cow.

He said: “Fat cows or thin cows are not happy cows.”

He also suggested that a single-group system works more efficiently than having dry cows in two groups.

“Only one dry cow diet is needed; it is not necessary to have a far off and a close up group with different diets.”

Reducing stress in dry cows in the run-up to calving is important too. Mr March warned against moving or regrouping cows in the five days prior to calving.

Age at first calving

The Howells calve their heifers at an average of 24 months.

This has been achieved by regularly weighing calves to ensure they are on track to hit an average target weight of 370kg for breeding at 15 months.

Monitoring weights helps determine if heifers are going to achieve key milestones. For example, heifers need to be 50% of their mature weight to reach puberty, a target which should be met at about 12 months of age to allow heifers to have several cycles before they are served to maximise conception rates at first service.

Calving at 24 months of age is regarded as the most efficient in terms of enteric and feed emissions.

The Howells have used sexed semen for breeding replacements in recent years, but with a good number of heifers now in the system, they have reverted to greater use of conventional semen.

Disease monitoring

Bulk milk sampling is now used to detect disease early and prevent further spread after an outbreak of IBR.

With funding from the AHDB HerdAdvance project, that outbreak was detected after milk was tested for IBR, IBR gE antibodies, leptospirosis, liver fluke and neospora.

Milking cows and heifers are now vaccinated against the disease.

The farm’s vet, Sara Melo, of Dyfed Farm Vets, also recommended using milk recording data to identify any health issues. For instance, the fat to protein ratio in early lactation can indicate negative energy balance.

If that ratio is greater than 1.4, the cow is likely to be in negative energy balance and too much body fat is being mobilised, increasing the risk of metabolic disorders and associated poor health and fertility.

Ms Melo said alarm bells should ring if there is a 15% rate of ketosis in the herd and an 8% mastitis rate in the first 30 days of the lactation. At Blaengelli, there was only one case of each in 2021.

Carbon emissions

Blaengelli’s baseline carbon footprint for the year ending March 2022 was 0.66 CO2e/kg of total output for the farm enterprise, including the carbon generated from meat production of cull cows.

Purchased feed and methane produced by the livestock, at 29% and 37%, are the biggest contributors to that figure.

Russell Thomas, of Kite Consulting, said further improvements in feed efficiency, to reduce purchased feed requirements could help reduce emissions.

He said: “A modest 0.02kg/litre over 1.5 million litres of milk sold is equivalent to 30 tonnes.”

He also suggested replacing soya as the protein source in the ration and for greater use to be made of protein-rich legumes.