The second objective is to set the farm up for spring grass. Many farmers do not realise that the grazing season begins in the autumn, and that autumn management of grazed grass is the primary factor influencing the supply of grass available in spring on any farm.
To provide enough for grazing in early spring, grass has to be carried over from the autumn period due to low grass growth rates during the winter period. Faraway pastures are always greener, and spring grass is a much better feed for a cow than autumn grass. So it is important that we get the autumn management right so we have a good supply of high-quality spring grass available next February.
Start of Closing
The start date of beginning the last rotation in autumn and the cover of grass grazed will have a large influence on the supply of grass available in early spring. The last rotation needs to be planned to have grass early in spring. The length of the last rotation should not be greater than 45 days and at least 30 days, for example, October 16 to November 16.
The last grazing rotation should have begun around October 7-10 for most farms. This date will vary a small bit according to soil type and to a lesser extent with stocking rate. For farms with a difficult soil type, closing up should have begun in last days of September.
Every one-week delay past the target of October 10 in closing up the farm will reduce grass supply in spring by 100kgDM/ha. Later closing will also reduce the level of autumn and winter grass growth.
Date when 60pc of the farm is closed
This is a very critical date. For most farms this is early November. This is because most of the grass available in early spring has been grown in October. Very little growth occurs over the winter months so most of the grass available in February and March is carried over from the previous autumn/early winter.
The target is to have about 60-65pc of the farm closed up by the first week in November. For those farms that have a high feed demand in spring, earlier closing up must be considered. This should be over 70pc of the farm closed for farms with a higher stocking rate. It is important to carry more grass across the winter for farms with higher stocking rates as demand for feed is higher.
Drier paddocks/fields with the best access should be targeted to be closed in October as these will carry the most grass.
John Maher is a Teagasc Grass10 advisor