The most important task any farmer will undertake over the next few weeks is to ensure that the farm is closed off properly to have an adequate supply of grass next spring, writes Daniel Hession.
What is the value of autumn grazing?
There is a lot of potential to make better use of grass on farms in autumn. Every extra tonne of grass utilised is worth €181/ha to a dairy farm and €105/ha to a dry stock farm.
Utilising extra grass and lengthening the grazing season to reduce the length of the
expensive housing period and increase animal performance is the key objective.
Why is autumn grassland management
important?
The grass growing season actually begins in the autumn. Whatever you do in the autumn has a big
influence on grass production in the following spring and early summer, because 60% of the herbage available for grazing next spring will be grown in the autumn and winter.
What are the aims of autumn grassland management?
The focus of autumn grazing management is to increase the number of days at grass and improve animal performance, but also to set up the farm to grow grass over the winter and provide grass the following spring.
When should I start closing paddocks?
Each one-day delay in closing after October 10 can
reduce spring herbage mass by 15kg of dry matter per head per day.
Have at least 60% of the farm closed by the end of the first week of November, with the remaining 40% grazed by early December.
What are the general guidelines when closing paddocks?
Choose drier paddocks, paddocks close to the yard, or sheltered paddocks, to close first so that they will be the first ones grazed in spring.
Close the wettest paddocks next in the rotation, followed by the remaining paddocks.
All paddocks should be tightly grazed in the final
rotation (to 3.5cm-4cm), to
encourage tillering over the winter.
In wetter conditions, use younger or lighter animals, or dry cows, to achieve this residual. The closing grass cover in early December should be, on average, 5cm-6cm (500kg of DM/ha) with paddock pre-grazing yields ranging from 4cm to 8cm (200-800kg DM/ha).
What tools can I use to help me close paddocks on time?
The autumn rotation planner is a tool to help extend the grazing season into late autumn. If followed, it will ensure that paddocks are set up correctly for grazing the following spring.
The 60:40 plan is based on having proportions of the farm closed by certain dates.
The 60:40 autumn rotation plan will not tell you if you are grazing paddocks that have too much grass, and it will
not tell you if you are not achieving desired post-grazing residuals.
You will have to gauge that by walking through your paddocks or fields and assessing either visually or by measuring.
How do I complete a 60:40 planner?
The table, above left, shows a completed 60:40 autumn rotation planner.
The difference between a dry farm (closing October 10) and a heavy farm (closing
October 1) can be seen.
For a dry farm, 60% should be grazed within four weeks and the remaining 40% in the next four weeks.
On a wetter farm, this changes to 60% grazed in four weeks, and the remaining 40% in three weeks.
In practical terms, this means that priority animals are housed first, and those that do not require high levels of performance are maintained at grass.
Over time, groups of animals can be housed, reducing the number of animals at grass.
Let’s take the example of a farm with 20 hectares, and
October 10 as the start of closing; 60% of the area should be grazed and closed by November 3, which is 24 days from the start of closing.
That requires grazing 0.5ha each day, or 3.5ha per week (by dividing the 24 days into 12ha, which is 60% of the 20 ha). From November 3 (date of 60% grazed) until housing, and taking December 1 as the housing date, allows 28 days to graze the remaining 40% (40% of 20ha is 8 ha, divided by 28 days, so approximately 0.3ha needs to be grazed each day, or 2ha per week).
Fill in the table, above right, with the details for your farm.
How do I deal with wet weather?
A flexible attitude is required. Use the most sheltered and driest paddocks when grazing in wet weather. Do not fear grazing animals into the autumn; they can be housed if soils get too wet. Block grazing and back-fencing are as important in the
autumn as the spring,
especially when grazing higher covers ( greater than 1,800kg DM/ha).
Dividing a paddock up and moving animals once a day is the best way of utilising grass in autumn. Three main methods of dividing larger fields into grazing divisions are strip grazing, spokes of a wheel, and block grazing.
On-off grazing can been
successfully used to retain animals at pasture during periods of heavy rainfall.
Autumn grazing