According to Teagasc, each additional day at grass in the spring has been shown to be worth just under €3 per cow per day.
The objective is always to get cows to grass as early as possible in spring and early spring grazing awakens the grass and initiates growth. Good graze-out will remove dead material that has built up over the winter and conditions the sward to produce new leafy vegetative growth.
Ideally, once you start grazing and weather conditions continue to allow, it is advisable to keep grass in the daily diet of the cow. Grazing-off ground too quickly will mean the first rotation is too short, so grass simply isn’t available at the beginning of the 2nd rotation. Not grazing enough ground each day, means the 1st rotation is too long, therefore surplus grass needs to be removed in the 2nd round, which can hamper grass growth, while also not creating a “wedge” of grass on the farm. To avoid either scenario, the most efficient way to allocate spring grass is to use a Spring Rotation Planner.
Spring Rotation Planner
The Spring Rotation Planner is a tool that divides the area of your farm into weekly portions and allows for careful planning of the first grazing rotation. It will help ensure grass is allocated across the spring to get to “Magic Day” – the day, usually in early to mid–April, when grass growth meets farm demand.
Grazing a percentage of the farm each day also ensures you are creating a “wedge” of grass growth, so you will have sufficient grass to get through the 2nd rotation. However, much of this rests on if the farm was correctly closed off during the autumn period.
There are various online tools to generate a spring rotation planner for your farm, or you can simply do it with a pen and paper.
100 % grazed
Taking an example of a 25 hectare farm on heavy ground, with a turnout date of 1st March and targeting the first rotation to end on 20th April.
Farm size = 25 ha
Date 40% to be grazed = 24th March (23 days after turnout)
Multiply the number of days grazing by the total area:
40% = 0.40 x 25 ha = 10 ha to be grazed between 1st and 24th March (23 days) =
0.43 ha per day or 3 ha per week.
Date 100% to be grazed = 20th April (27 days to graze the remaining 60% of the farm)
Remaining 60% of area to be grazed = 0.6 x 25 ha = 15 ha to be grazed
=0.55 ha per day or 3.9 ha to be grazed per week from 25th March to 20th April
The spring rotation planner allocates a certain percentage of the farm to be grazed each day, therefore it is important to stick to the target area, avoiding the temptation to graze more or less. Using a strip wire to allocate grass on a 12-hour basis will optimise utilisation of the sward and minimise wastage of your grass.
The target ‘post grazing residual’ for the first rotation is approximately 3.5 cm. If the herd is hitting this target they need to be supplemented with silage or concentrates to ensure they are adequately fed. If they are not hitting that target, then consider reducing silage or concentrate feeding. it is recommended to feed spring calving cows 3–4 kg of concentrate per cow per day to meet her energy requirements.
Grazing low covers will help to increase the area grazed if you start to fall behind your targets. Also, lower covers are easier to graze in wet weather. Remove silage from the diet if you need to increase grass intake to hit your targets.
Managing spring grazing in wet conditions
In periods of wet weather, use on/off grazing to maintain grass in the diet. The best way to manage this, is to turnout animals to the allocated area for a 3-hour period, after which, animals should have achieved their required intake and finished grazing. Following this, bring them back indoors which will reduce damage to the field.
To maximise grass utilisation in the spring, good farm infrastructure is a huge advantage as roadways with plenty of entry points into each field provides good access to the grazing platform.