As we all know grass is the cheapest and most nutritious feed available and you need to get in as much good quality grass as possible into your cows. On average, the cost of producing 1kg of liveweight gain or 1kg of milk solids from grazed grass is 80% to 85% less when compared with an intensive concentrate-based system. By measuring your grass you will get the data needed to make informed and timely decisions on your grassland management. Take the guesswork out of managing your grass, know when to reduce/cut out meals in spring, identify grass surpluses and deficits, know when to cut surplus grass for silage etc.
We have already discussed the option of using a Plate Meter to measure grass HERE
In this post we are going to look at how to measure grass using shears, scales and quadrant – the cut and weigh method.
Using a 0.5m x 0.5m quadrant, place it in an area that is representative of the amount of grass in the paddock.
With the grass shears cut the grass within the quadrant. This should be cut leaving a residual of 3.5 and 4cm to reflect a normal residual left when grazing. This gives the available grass cover for grazing.
Place the cut grass into a bag and weigh using hanging scales.
We have a Grass Measuring Ready Reckoner available to make the cut and weight method more efficient. With the dry matter% and the weight of your grass, you can quickly see the cover available in your paddock.
Formula to calculate the Dry Matter Yield in the Paddock:
Weight of grass (kg) x grass DM% x 40,000 = kg DM/ha in the paddock
Cut and Weigh Example:
Grass cut within the quadrat weighs 200g (0.200 kg)
(Remember to subtract the weight of the empty bag)
Grass DM% = 16% (0.16)
0.200 kg x 0.16 x 40,000 (there are 40,000 quadrats in a hectare) = 1,280 kg DM/ha.