How many block calving herds are there in the country?

Wednesday, 18 August 2021

By Chris Gooderham

In 2020, according to BCMS calf registrations, 16.0% of dairy farmers in GB were operating block calving systems. A further 30.6% can be identified as all-year-round; spreading their calvings relatively evenly over the year. That means 53.4% of farmers appear to fall between the definitions for block calving or all-year-round (AYR) calving.

When we look at the number of calf registrations, the picture changes slightly. The farms referred to as “non-defined” above had the smallest number of calf registrations in the year, averaging 120. In comparison, the AYR group averaged more than double that, at 250 registrations.

As a result, in terms of calf registrations, we would estimate around 19.6% are from block calving herds, 43.8% from AYR herds and the remaining 36.6% from herds falling between those two definitions. 

We have been encouraging farmers to review and identify which system they operate and which one is best for them through Optimal Dairy Systems. Our Farm Business Review tool allows farmers to then check and compare how their performance measures up against likeminded farmers.

Notes and definitions

Historically, the breakdown of system in GB has been based on farmers’ self-assessment of which system they believe they operate. This is the first time we’ve been able to see the breakdown based on calf registrations for each farm in the country.

The data excludes any farms where all registrations were for non-dairy calves, and also excludes farms who had less than 25 calf registrations in the year.

Our farm key performance indicators suggest block calving herds should target 90% of calvings within a 6 week window, although the “good” level is set at 80%. For this analysis we have used a wider definition of 4 months and 80% of registrations as set out below:

  • Spring block: 80% of registrations occur within 4 months from 1 Feb to 31 May
  • Autumn block: 80% of registrations occur within 4 months from 1 Aug to 30 Nov or 1 Sep to 31 Dec
  • Other block: 80% of registrations occur within 4 months other than defined in spring or autumn block
  • Dual block: 90% of registrations occur within the spring block or autumn block windows defined above.
  • AYR: Registrations are spread relatively evenly throughout the year, but that can be based on a 12 month, 11 month or 10 month calving system. 12 month means each month sees 3.3%-13.3% of annual registrations. 11 month means 4.1%-14.1% of annual registrations in 11 months of the year, and 10 month means 5%-15% of annual registrations in 10 months of the year.
  • Non-defined: covers any farm not falling into one of the other categories.
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Chris Gooderham

Science and Environment Director

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