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Case Study SRUC Dairy Herds:
The effect of reducing milking frequency in response to Covid 19

Are there benefits to be had from moving from a 3x milking system to 2x?

Perhaps the main reason to change is to reduce milk output, based on your milk buyers requirements with the current impact of COVID-19 on dairy markets. However, reducing milking frequency may not necessarily significantly reduce milk output as discovered at SRUC’s three dairy units.

  • The milking interval will have an impact on the response to 2x milking. Keeping to a 12 hour interval could minimise the drop in production.
  • Be aware that cell counts and mastitis count increase, but with attention to detail in the parlour and keeping cows clean, milk hygiene quality can be maintained.
  • There are benefits for staff, reduced labour and other costs associated with a 3rd milking.

Case Study – The Effect of Reducing Milking Frequency

Across the three dairy units run by SRUC in the South West of Scotland, management has recently changed from 3x to 2x milking. This change took place on the 23rd March as a precaution to reduce labour demand in case of having to deal with staff self-isolating or off sick due to COVID-19.

With 3x milking, the milking intervals were 8,7 and 9 hours apart (milking at 4am, 12pm and 7pm) and with 2x milking, 12 hours apart (milking at 6am and 6pm). It was important to stick to 12-hour milking intervals, as the farms manager wished to retain the night milking staff who previously did the 3rd milking, but also to minimise any loss in milk output. There is often a bigger drop in yield observed when milking intervals are not even when reverting back to a 2x system.

It was expected that there would be a bigger drop in milk production across the three units. However, there has been very little change in output or milk composition as shown in the table below, which compares milk output and composition before implementing 2x and then at roughly 3 weeks and 6 weeks later. Milk yield per cow actually increased initially at Crichton but this is likely due to lower producing cows either being dried off early or culled. There was very little difference in the days in milk at each unit between the reported time periods (no more than 5 days), so this would have little influence on yield per cow.

 3 x Milking2 x Milking2 x Milking
Daily average from 14th-22nd MarchDaily average from 11th-19th AprilDaily average from
27th April-5th May
Acrehead FarmAverage no. milking cows = 180Average no. milking cows = 180Average no. milking cows = 180
Milk output (litres)5,6305,3595.589
Milk yield/cow (litres)31.329.831.05
Butterfat (%)4.244.284.26
Protein (%)3.493.473.51
SCC (x1000)8982100
Barony FarmAverage no. milking cows = 180Average no. milking cows = 172Average no. milking cows = 162
Milk output (litres)5,6305,1555,266
Milk yield/cow (litres)31.330.032.5
Butterfat (%)4.334.404.45
Protein (%)3.243.243.20
SCC (x1000)90112200
Crichton FarmAverage no. milking cows = 176Average no. milking cows = 179Average no. milking cows = 177
Milk output (litres)5,4685,6975,830
Milk yield/cow (litres)31.131.832.9
Butterfat (%)4.224.154.08
Protein (%)3.313.283.27
SCC (x1000)968298

Note: data is based on average figures over a 9-day period before moving to 2x on 23rd March and post-change, a 9-day period approximately 3 and 6 weeks later. Data is from Milk Payment Testing Results through NML. Out of the 180 cows at Acrehead, on average 45 cows were still milked through the robot.

There was a concern that reducing milking frequency could lead to higher cell counts and more mastitis. However, early indications are that cell counts were not affected and so far, the number of mastitis cases is on a par or less than in the previous months, as shown in the following table.

MonthAcreheadBaronyCrichton
April 20492
March 20285
February 20475
January 204104
December 19585

It has been observed that despite little effect on cell counts or mastitis rates, some cows do appear to be carrying a lot of milk in the last hour prior to milking, with possible discomfort.

With one less milking per day, it was thought that the average lying time would improve. The three farms use the Cow Alert system from Ice Robotics Ltd for heat and lameness detection and the system also records lying time. Under ideal conditions, cows should lie down for 12-14 hours/day and as a rule of thumb, an extra hour of lying time will give roughly an extra litre of milk.

The average lying times for two of the herds before and after the change in milking frequency are detailed below. Lying times were only available for Acrehead after the 24th March when 2x milking had already commenced.

FarmLying Time on 3 x Milking (hours/day)Lying Time on 2 x Milking (hours/day)
Crichton12.011.8
Barony10.210.4

Note: Lying times are a daily average between 14th – 22nd March and 10th- 19th April

There is an overall higher lying time at Crichton due to the recent installation of mattresses, improving cow comfort. There was no difference in lying time when comparing 3x versus 2x milking, possibly due to the cows producing more milk at the 2x milkings (as yields have been similar), meaning each milking is taking slightly longer.

Other observations from this management change are that staff appear to be more relaxed, with more time in the middle of the day for other jobs, without the lunchtime milking. Less stress and less time pressure on staff are positive for mental health, job satisfaction and being able to retain staff in the long-term. These are all very important considerations on a dairy farm, with herd performance being only as good as the people employed.

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