Shift in calving patterns impact on GB milk profile

Dairy farms have shown an increased focus on calving system over the last ten years. But how has the increase in block calvers and all year round (AYR) systems impacted on the overall profile of GB milk production?

We used our milk forecasting calculator to create a milk production profile based on the national calving patterns, split by group. Then we looked at how the changes in calving patterns between 2011 and 2020 impacted on that milk forecast.

Our analysis shows that the move away from non-defined systems means they now contribute 5.6 – 6.2m litres per day less milk to overall GB milk volumes. The increase in AYR calving has offset this by contributing 2.5 - 2.7m litres more milk per day to volumes. Both of these impacts are relatively stable through the year.

The more seasonal impact has come from the rise in block calvers. This has:

• Added 3.8m litres per day in April and 3.7m litres in May, pushing up the spring peak by around 2%.
• Added 3.6m litres per day in October and 3.8m litres in November, helping to lift the previous seasonal trough
• Contributed only an additional 2.4m litres per day in August, and 2.6m litres per day in July.

The net impact on GB milk production can be seen on the following chart.

Over the last ten years, the shift in calving patterns has made the spring peak higher, lifting April by 2.4% (0.8m litres per day) and May by 1.9% (0.9m litres in May). It has also reduced milk production in the summer, dropping July by 1.8% (0.6m litres per day) and August by 2.7% (0.9m litres per day). In doing so, it has moved the seasonal trough from October/November to August/September.

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