Making Milking Hum – Know your numbers and the opportunity

By Josh Wheeler – QCONZ

Milking is a job that requires a series of tasks to be performed for each cow milked. Depending on your herd size, by the end of milking those tasks will have been repeated hundreds of times. Milk twice a day (TAD) ,and you will be back to repeat those tasks at the next milking, and then the next milking, and so on, until finally you dry the girls off at the end of the season and you give the body a rest.

Every now and again farmers should take some time to step back and to review how milking is going. Is the milking routine working for the cows, for the staff, themselves, and their partners?

To analyse performance, you need to know some key performance indicators (KPIs):

  1. Average row time – the average time it takes to milk one complete row of cows (expressed in minutes and seconds).
  2. Work routine time (WRT) – the amount of time used to milk (expressed in seconds per cow/bail multiplied by the number of people milking).
  3. Cows per hour – the average number of cows milked in one hour.
  4. Cows per hour per person – as per previous, divided by the number of people milking.

Once you have the above information you will be in a position to identify any opportunities to make milking more efficient, spend less time milking, and reduce the potential for over-milking and mastitis.

So let’s look at how you work out your farm’s milking KPIs.

Average row time calculation

To work out the average row time for a herringbone take the total milking time in minutes and divide that by the number of rows of cows milked (this does not include setup or wash routine).

Total milking time = the time from first cups on to last cups off (mins)
Rows milked = the total number of cows milked, divided by number of bails per side

So if the total time to milk a herd of 300 cows through a 20 aside herringbone is 2 hours 25 minutes  (or 145 minutes) then:

300 cows divided by 20 bails = 15 rows
So the average row time is 145 min ÷ 15 rows = 9.66 minutes (9 min 40 sec)

Work routine time calculation

To calculate the WRT convert row time to seconds by multiplying the average row time by 60 and then multiply that number by the number of milkers. For our example 20 aside herringbone to work out the WRT with one person milking:

Convert row time to sec per row 9.66 x 60 sec = 80 sec/row
WRT per person equals 580 sec ÷ 20 bails x 1 person = 29 sec/bail
Note: If 2 people milk WRT 580 sec ÷ 20 bails x 2 people = 58 sec/bail

Cows per hour calculation

To work out the average number of cows milked per hour, divide the total number of cows by the total milking time in minutes, and multiply that number by 60 to give cows per hour.

So If we milk 300 cows in 2 hours 25 minutes (145 min):

Divide 300 ÷ 145 mins = 2 cows/min
Then 2 cows/min x 60 (min in an hour) = 120 cows/hr

Cows per hour per person calculation

To establish cows milked per hour per person divide the number of cows per hour by the number of people milking.

Milking 120 cows/hour with 1 person (120 ÷ 1) = 120 cows/hr/person
Milking 120 cows/hour with 2 people (120 ÷ 2) = 60 cows/hr/person

What do the numbers mean?

So now you know how to calculate your KPIs for your dairy, what do they mean, and what’s the opportunity?

The KPI results for our example farm milking 300 cows in 20 aside herringbone with 1 milker:

1.       Average row time 9.66 min
2.       Work routine time (WRT) 29 sec
3.       Cows per hour 120 cows per hour
4.       Cows per hour per person milking 120 cows per hour

Average row time

If we could improve our WRT then we will improve our average row time and reduce our total milking time. Your average row time allows you to compare your dairy’s performance to any other herringbone, regardless of the size.

The table below provides a benchmark for inefficient and efficient row times and what might be achieved if the MaxT (maximum milking time) strategy is applied.

Inefficient row time Efficient row time MaxT
>9.5 mins 7.5 – 8.5 mins 6.5 – 7.5 mins

Work routine times

So what do we know about work routine times on NZ herringbone farms?

What is considered an efficient WRT will vary depending on the size of the dairy, for example, If we were to compare one-person milking in a 12 aside herringbone, to one person in a 20 aside herringbone, the 20 aside will have a faster WRT as less time will be spent waiting for cows to finish milking. However, knowing your WRT allows you to identify where opportunities for improvement might lie.

Typically, the biggest improvement in WRT is made by optimising the milking routine i.e. implementing an efficient “bunny-hopping” approach in herringbones.

The table below shows benchmarks for inefficient, efficient and achievable WRT through the implementation of technology (auto teat sprayer) for an 18 – 24 aside herringbone with one person milking.

Inefficient WRT Efficient WRT WRT with Technology
>28 secs 22 – 24 secs 18 secs

Cows per hour

Once you know your cows per hour milked then you can start to look at the opportunities for improving your average row times and increasing your cows per hour milked.

So, if we take our 20 aside herringbone example milking 120 cows/hour, with 9.66 min row times, and 29 sec WRT, what are the opportunities and savings if we could achieve a 8.5 or 7.5 min row time?

Options Average row time WRT Cows/hour Saving / milking
Current system 9.66 min 29 sec 120 n/a
Efficient 8.5 min 25.5 sec 141 17.5 min
MaxT 7.5 min 22.5 sec 160 32.5 min

Examples of calculations to work out the opportunities

The following examples show the calculations for working out the WRT, cows/hour and savings for the 8.5 minute example.

WRT calculation (8.5 min row time)

Row time min x 60 sec = sec per row
Sec per row / cows milked x no. people = WRT
8.5 min x 60 sec = 510 seconds a row
510 / 20 cows milked x 1 = 25.5 second WRT

Cows per hour (8.5 min row time)

Hour (60 min) ÷ row time = rows per hour milked
Rows per hour x number of cows in row = number of cows milked per hour
60 min ÷ 8.5 min = 7.06 rows per hour milked
7.06 x 20 cows = 141 cows per hour milked

Savings per milking (8.5 min row time)

Min per row x number of rows milked = total milking time min
Current milking time – projected milking = time saved per milking
8.5 min x 15 rows = 127.5 minutes for milking
145 min – 127.5mins = 17.5 minute saving


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