Grass Watch 21


Grass Watch 2021

Grass Watch is designed to demonstrate the value of grass in milk production and the impact this variable food source can have on key components such as butterfat and Protein(%).
This key information on grass quality can help shape a feeding program to achieve the results of a modern day high yielding herd. Samples are taken Weekly every Monday from the Paddocks the cows are grazing and are sent off to be analysed. 15 monitor farms are used across Ireland and are combined to achieve average. One of the farms is a Corby Rock customer farm belonging to father and son Tom and Edward Treanor. Program runs until November.
 If you would like to receive weekly updates please submit your interest in the form on the right.

Overview of this week results by Trouw’s Dairy Technical Support Coordinator 

Grass Quality Summary:

  • Grass dry matters were relatively poor, averaging 15.3%, curtailing grass dry matter intakes on average by approx. 1kgDM/head/day. As drying conditions improved later in the week and are set to continue into early this week, grass dry matters should be increasing closer to 18% – improving dry matter intakes.


  • Crude proteins continue to improve averaging 20.3%, but still ranging considerably. Milk ureas across monitor farms currently range from 12mg/dl to 20mg/dl.


  • Grass digestibility continues to decline quite rapidly across most monitor farms.


  • Sugar levels continue to gradually decline as growth and nitrogen utilization gradually improve.


  • Oil levels continue to gradually rise – averaging 4.0% (Butterfat risk).


  • Grass dry matter intakes in many cases are around 15kgDM/head/day – capable of supporting maintenance requirements plus 17.3 litres . With conditions improving grass dry matter intakes will hopefully improve closer to 16kgDM/head/day and above – supporting maintenance plus 19.4 litres.


  • With sugars decreasing risk of milk fat depression from RFC and Acid Load (both a result of high sugars) are decreasing but still remain ‘high’. With increasing fibre levels in grass, risk from Fibre Index is ‘moderate’. Risk from RUFAL (unsaturated oils) remains ‘low’.
Trouw Nutrition - Claire Beckett

Trouw Nutrition – Claire Beckett

Management Notes:

Keeping on top of grass quality and maximizing dry matter intakes…….

1.Maximising grass dry matter intakes:

    • Maintain target pre (1400-1500kgDM/ha) and post grazing covers. Entry at less than 1400kgDM/ha can restrict density of bite full and in turn dry matter intake
    • Ensure correct allocation of area to achieve desired intakes – often the limiting factor!
    • Graze at 3 leaf stage to increase density of bite full
    • Maximizing time spent at pasture, minimize time spent in collecting yard
    • Maintaining a dense sward
    • Chose palatable grass varieties – proven in Teagasc grazing trials
    • Pre-mowing + wilting (discussed below)
    • Ensure ample clean water availability and minimize distance to drinkers
    • Room to graze – especially impacts heifer performance
    • If feeding a buffer feed offer before evening milking


 2.Pre-mowing and wilting

    • Can increase dry matter intake by 1.0-1.5kgDM/head/day
    • Helps maintain target residuals. Typically cutting to a residual of 200kgDM/ha
    • Can help improve palatability of ‘soar’ grass and stronger grass around dung pats, improving grass utilisation
    • Regrowth is quicker and more palatable compared to with topping
    • Not to be used as a method for getting heavy covers grazed!!
    • No conditioner on mower required

The dry matter (DM) content of forage (measured as a percentage) is the proportion of total components (fibres, proteins, ash, water soluble carbohydrates, lipids, etc) remaining after water has been removed.
Knowing the dry matter percentage of forage is important. The lower the dry matter content, the higher the fresh weight of forage required to achieve a target nutrient intake, whether this is grazed grass or conserved forage.

In Ireland, due to the climate, we typically have very low grass growth rates in the spring and again in the autumn, with maximum growth rates being achieved during the month of May. Although there is little we can do about the weather in the spring and autumn periods, there are a number of measures we can take to improve grass production at the shoulders of the season.

If you would like to be updated with the latest results fill out the below contact form and we will keep you up to date.

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Weekly Dry Matter

  • Min Dry Matter (%)
  • Avg Dry Matter (%)
  • Max Dry Matter (%)
  • CRM Monitor Farm Dry Matter (%)

Predicted Milk Yield From Grass Only: Based on Average Grass Energy

  • MY @ 12kg DMI
  • MY @ 14kg DMI
  • MY @ 15kg DMI
  • MY @ 16kg DMI

Crude Protein %

  • Min Crude Protein (%)
  • Avg Crude Protein (%)
  • Max Crude Protein (%)
  • CRM Monitor Farm Crude Protein (%)

Oil Process A

  • Min Oil (A)
  • Avg Oil (A)
  • Max Oil (A)
  • CRM Monitor Farm Oil (A)

ME     (MJ/kg)

  • Min ME (MJ/kg DM)
  • Avg ME (MJ/kg DM)
  • Max ME (MJ/kg DM)
  • CRM Monitor Farm ME (MJ/kg DM)


  • Min NDF %
  • Avg NDF %
  • Max NDF %
  • CRM Monitor Farm NDF %

Weekly Grass Growths (PastureBase Ireland)

  • kg DM/ha/day

Weekly Grazing Information

  • Grass ME (MJ/kgDM)
  • Grass Crude Protein (%)

Butter Fat Alert (Average)

  • RFC Intake
  • Acid Load
  • Fibre Index
  • RUFAL Intake

Turnout – Getting More From Grass

Short informative video on key essentials to maximizing yield from grass systems.

Energy from Grass