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The importance of Spring Grazing for Winter Milk Herds


Winter milk herds require a spring grazing plan that will increase grazing days and pasture quality, is flexible to implement, and is tailored to the particular demands of that farm. James Dunne, Dairy Systems Specialist, Teagasc Ballyhaise, has important grazing management advice for this Spring

Impact of utilised forage

Over the last number of months the focus has rightly been on winter diets and concentrate feeding for autumn calving systems however, increasing forage utilised remains the most effective means of improving milk sales from the farm while controlling the largest single input cost i.e. concentrate feed. When benchmarking these farms on their financial performance 45% of the variation in whole farm profit between winter milk farms can be explained by this single metric; by comparison milk yield per cow explains around 5% of the difference. When milk supply patterns for different calving patterns are examined – a typical 65:35 Spring / Autumn split calving system will potentially produce over 80% of its annual milk volume during the grazing season (Feb to Nov).

"Second peak" effect

Block-autumn calving groups within the Johnstown Castle herd have typically averaged >90% of daily milk solids yield, (1.85 to 1.95kg per cow) compared to spring calving counterparts in the April to July period. This is sometimes described as a ‘second peak’ effect. In order to capitalise on this high margin milk, it is important the farm is managed correctly throughout the spring to ensure maximum quality grass (digestibility) through the peak growth period.

Clearly, grazed pasture forms a significant part of the annual milking diet for the autumn caved cow and the importance of good grazing management is further underlined. Winter milk herds therefore require a spring grazing plan that ultimately shall increase grazing days and pasture quality, is flexible to implement, and is tailored to the particular demands of that farm. The objective is to graze the entire area available in an extended first rotation from early-mid February to early-mid April. This helps to ensure the farm has adequate grass recovery for the second rotation, improves sward quality and reduces daily feed cost.

Spring Grazing Management Advice

Some important  grazing management advice this spring:

  • Follow your spring rotation plan, at least 1/3 of the area should be grazed by end of February (or 7-10 days later on heavier soils) and 2/3 area by mid-March (or 7-10 days later on heavier soils). This is readily achievable given the high intake capacity of autumn calved cows provided grazing commences by mid-February where possible.
  • The minimum allowance per grazing in early spring should be 5 - 6kg DM per cow. This can be achieved in a 3-4 hours grazing after morning milking until noon. Cows should return to the shed after this 3-4 hour grazing bout where ground conditions are less favourable in order to minimise damage.
  • Graze some lighter covers (<800kg DM per ha) at first turnout to settle cows into grazing correctly.
  • Graze tightly to 3.5-4.0cm residuals to ensure excellent quality regrowth.
  • As grass allowance increases, add a second grazing bout after pm milking (earlier evening milking is required in order for this to take place i.e. 3.30pm).
  • Concentrate allocation can be held steady until grass allocation is >10kg DM per day. This stabilises intake and milk yield.
  • Daily silage allocation should be gradually reduced to balance increasing grass allowances – aim to have silage finished before morning milking to encourage grazing post-milking. Total daily feed intake should be maintained however with grazed grass offsetting the reduction in silage intakes.
  • Maintain average farm cover at 500-550kg DM per by end of 1st rotation. Having a simple spring feed budget helps to monitor progress and allow adjustments to be made.

More information from Teagasc on Spring Grassland Management can be found here