The oldest problem in dairy
1.57 million cows in Britain. The same 3 hard weeks. Every year.
In the 3 weeks after she calves, she needs more energy than she can eat. What she does in those weeks shapes the rest of her year, and how many more she gets. This page sets out the global scale, what it costs, and the one observable change in her day that supports her through those weeks.
A word on our Capitals
Yes, we’re Americans, and yes, we Capitalise Things. This time it’s Intentional. Every Capitalised term on this site (Behaviour, Dry Matter Intake, Negative Energy Balance, Body Condition, Days in Milk, Peak, Persistency, Fertility, Reproduction, Herd Life, Emissions, Milk, Milk Production, Health and Ketosis) marks an area of future potential study we’d like to explore with you on British farms: the signs of the metabolic recovery and behavioural change a trial looks for. Bear with us. The spelling, at least, is British.
Recorded on working US dairies, 2014–2017. Captions cover the narration and the founder.
How many cows
Every dairy cow. Britain first, then Europe, then the world.
Every one of these cows calves, and every one of them meets the same weeks after calving, every year.
Great Britain
1.57million
cows in the GB milking herd
1,570,000 cows in the GB milking herd (1 July 2026) → 1.57 million
AHDB 2026 · UK
European Union
19+million
dairy cows milked in the EU-27
19,221,660 dairy cattle milked in the EU-27 in 2024 → 19+ million
FAOSTAT 2024 · FAO, Rome
The world
290+million
dairy cows milked worldwide
294,577,237 dairy cattle milked worldwide in 2024 (FAO estimate) → 290+ million
FAOSTAT 2024 · FAO, Rome
Every year, the same
Known for decades. Planned months ahead. Happens every year.
None of it comes as a surprise, and none of it has gone away. It is the biology of making milk.
Every year
The same 3 weeks
The transition runs from 3 weeks before calving to 3 weeks after. The trouble gathers in the 3 weeks after.
Drackley 1999 · USA
Planned for
Planned months ahead
Her calving date is set the day she is inseminated, so the farm plans for those 3 weeks long before she reaches them.
Known science
Taught for decades
It is standard teaching in veterinary schools and agricultural universities, and it is still the hardest stretch of her year.
Where the trouble lands
Up to half of a cow’s clinical disease lands in those 3 weeks.
Across her whole life in the herd, the weeks just after calving are where trouble concentrates. A cow short of energy is the cow most at risk.
What it costs
The bills start in the fresh pen, and most never arrive as a bill.
They come out of the gap between the energy she needs and the energy she can eat. The biggest, the Milk she never made, is the last to show.
Per 1,000 cows per year
£339,497
up to £521,000 at the measured ceiling
£8,253 + £21,614 + £7,125 + £302,505 = £339,497
with lost Milk at the 16% ceiling:
£36,992 + £484,008 = £521,000
Milk at £0.35/L (Defra · UK, July 2026) · DMI Impact calculation, assumptions stated
About £533 million a year across Great Britain’s 1.57 million milking cows, up to £818 million at the ceiling.
1,570 × £339,497 = £533,010,290 · at the 16% ceiling: 1,570 × £521,000 = £817,970,000
DMI Impact calculation
Check the maths
- Great Britain’s milking herd: 1,570,000 cows (AHDB, 1 July 2026). In blocks of 1,000 cows, that is 1,570.
- What the transition costs per 1,000 cows a year (the 6 bills, in the order a herd pays them):
- Disease, treatment only: Ketosis 117 cases × €28.50 × £0.85/€ = £2,834, plus metritis 69 cases × $99.41 × £0.79/$ = £5,419, so £8,253. Sources: Macrae 2019 · UK; USDA NAHMS 2018 · USA; Steeneveld 2020 · Netherlands; Liang 2013 · USA; exchange rates are DMI Impact assumptions.
- Body Condition: 1,000 cows × 0.5 of a score × 135 Mcal = 67,500 Mcal ME, the energy in 63,606 kg of milk, ÷ 1.03 kg/L × £0.35/L = £21,614. Sources: NASEM 2021 · USA, p.34; 1.03 kg/L is a DMI Impact assumption.
- Fertility (16 to 22 days, Raboisson 2014 · France) is counted in days, not priced.
- Early culling: 1,000 cows × 1% extra culls × £712.50 = £7,125. Sources: Farmers Weekly 2024 · UK; 1% is a DMI Impact assumption.
- Emissions (+2.3% CO2e per tonne of milk per case, Mostert 2018 · Netherlands) are counted in their own units, not priced.
- Lost Milk, last to show: 1,000 cows × 8,643 L × 10% × £0.35/L = £302,505. At 16%: £484,008. Sources: Defra 2026 · UK; milk at £0.35/L (Defra · UK, July 2026: the lowest published month of Q3).
- Total: £8,253 + £21,614 + £7,125 + £302,505 = £339,497. With lost Milk at 16%: £36,992 + £484,008 = £521,000.
- Across Great Britain: 1,570 × £339,497 = £533,010,290, about £533 million a year. At the ceiling: 1,570 × £521,000 = £817,970,000, up to £818 million.
- What this assumes: the cost per 1,000 cows applies across every GB milking cow. The lost Milk bill rests on the +10% floor and +16% ceiling measured on 6 US dairies. That is commercial observation, not peer-reviewed: a percentage increase is anecdotal until scientific studies verify the correlation and the causation.
DMI Impact calculation (register row C-14), from register rows C-01 and C-05 to C-09.
A percentage increase is anecdotal until scientific studies verify the correlation and the causation.
What it looks like
Five days fresh, a rough calving, and looking thin.
“How long has this cow been fresh? Five days. She looks a little thin, doesn’t she? Yeah, she had a rough labour.”
Dr Kerry McGehee, Veterinarian, with Jeremy Setters, Herd Manager · filmed on a US dairy, 2014–2017, quoted as they said it
Every farm has her. The calving took more out of her than most, she is eating less than she needs, and what she cannot eat she takes from her own Body Condition.
Where the bills land
One gap. 6 bills, in the order a herd pays them.
Per 1,000 cows a year. Treatment comes first and full-lactation lost Milk comes last: the biggest bill is the slowest to show. Milk, like Body Condition and Fertility, is a lagging sign of how well she recovered from calving. 4 are priced; 2 are counted in their own units, because they do not convert cleanly to pounds.
01 · Disease, treatment only
£8,253
Ketosis £2,834 + metritis £5,419
Macrae 2019 · UK · USDA NAHMS 2018 · USA · Steeneveld 2020 · Netherlands · Liang 2013 · USA
02 · Body Condition
£21,614
1,000 cows × 0.5 of a score × 135 Mcal = 67,500 Mcal ME = 63,606 kg of milk ÷ 1.03 kg/L × £0.35/L
NASEM 2021 · USA, p.34
03 · Fertility
16–22 days
longer from calving to conception, per cow with subclinical Ketosis · counted, not priced
Raboisson 2014 · France
04 · Early culling
£7,125
1,000 cows × 1% extra culls × £712.50
Farmers Weekly 2024 · UK · 1%: DMI Impact assumption
05 · Emissions
+2.3%
CO2e per tonne of milk, per case of subclinical Ketosis: lower Emissions per litre start with fewer cases · counted, not priced
Mostert 2018 · Netherlands
06 · Lost Milk, last to show
£302,505
1,000 cows × 8,643 L × 10% × £0.35/L · at 16%: £484,008 · shows in full only over the whole lactation
Defra 2026 · UK · +10% to +16%: DMI Impact commercial dairies, not peer-reviewed, anecdotal until verified
The full working for each bill is in Check the maths above, and on the cost, step 2 of 4.
What changes
She gets up, she goes to the feed barrier, and she stays there longer.
That is the change to watch for. Her ration, your buildings and her genetics stay the same: only one thing about her day changes, and you see it in what she does before any record moves.
See it on your own cows
Your cows. Your times. Your records.
Your cows
You choose which fresh cows carry a wearable neurostimulation device, and each one is matched with 2 or 3 control cows in your own herd.
Your times
You decide when she is prompted to get up, and you watch her at the times you decide.
Your records
Your pedometers log every time she gets up and your collars log her cud chewing; your parlour meters and herd software show what follows. All the data stays with you.
90 days, 10 units, at no cost to you. No change to your ration or your treatment protocols.
The science, step by step
Want the why, in full?
Four steps, each with its own film: the biology inside her, what the gap costs, how the device works, and what the people who used it saw.
The evidence behind this page · 14 sources
Pound figures are DMI Impact calculations from these sources, written out beside each one. The +10% and +16% are DMI Impact commercial observation on US dairies, not peer-reviewed, and anecdotal until scientific studies verify the correlation and the causation.
- Corbett M, AHDB (2026) GB dairy population: the GB milking herd sees lowest level on record · UK · ahdb.org.uk
- FAO (2025) FAOSTAT Crops and livestock products: milk animals, raw milk of cattle, World and EU-27, 2024 · FAO, Rome · fao.org/faostat
- Drackley JK (1999) Biology of dairy cows during the transition period: the final frontier? J Dairy Sci · USA · doi.org/10.3168/jds.S0022-0302(99)75474-3
- Pascottini OB, Leroy JLMR, Opsomer G (2020) Metabolic stress in the transition period of dairy cows: focusing on the prepartum period. Animals · Belgium · doi.org/10.3390/ani10081419
- Defra (2026) Agriculture in the United Kingdom 2025 (average lactation 8,643 L) · UK · gov.uk
- Defra (2026) United Kingdom milk prices and composition of milk (July 2026: 35 ppl) · UK · gov.uk
- National Academies of Sciences, Engineering, and Medicine (2021) Nutrient Requirements of Dairy Cattle, 8th revised edition, p.34 · USA · nationalacademies.org
- Macrae AI et al. (2019) Prevalence of excessive negative energy balance in commercial United Kingdom dairy herds · UK
- USDA APHIS NAHMS (2018) Dairy 2014, Report 3: Health and Management Practices on U.S. Dairy Operations · USA · aphis.usda.gov
- Steeneveld W et al. (2020) Estimating the combined costs of clinical and subclinical ketosis in dairy cows. PLoS ONE · Netherlands · doi.org/10.1371/journal.pone.0230448
- Liang D (2013) Estimating the economic losses from diseases and extended days open with a farm-level stochastic model. MSc thesis · USA
- Raboisson D, Mounié M, Maigné E (2014) Diseases, reproductive performance, and changes in milk production associated with subclinical ketosis in dairy cows. J Dairy Sci · France · doi.org/10.3168/jds.2014-8237
- Mostert PF (2018) The impact of diseases in dairy cows on greenhouse gas emissions and economic performance. PhD thesis, Wageningen University · Netherlands · doi.org/10.18174/445487
- Macmillan S (2024) Advice on calculating cull cow costs accurately. Farmers Weekly (cites NMR 2023) · UK · fwi.co.uk