As we move towards autumn grazing, it is worth reminding ourselves that each extra day at grass in the back end of the year is worth €1.80/cow/day.
For many, growth rates have been much lower than normal over the last number of weeks and grass has been tight, resulting in many feeding concentrates and silage.
After the rain last week and the current high soil temperatures, growth rates are predicted to rise, so growth will recover.
Where growth is slow, it is important not to allow average farm cover (AFC) fall below 500kg DM/ha.
Continue to feed concentrate and silage if necessary to reduce demand and bridge the gap. Ensure all fertiliser applications are up to date and walk the farm weekly to assess growth.
Autumn targets
The target AFC, cover per livestock unit (C/LU) and rotation length are all dependent on stocking rate. Table 1 shows a set of targets for farms stocked at 2.5 LU/ha, 3 LU/ha and 3.5 LU/ha.
The table sets out what the targets are as we move through building grass to extend the grazing season and set the farm up for more days at grass in the spring.
Although the table will work for most farms, doing an autumn grass budget for your own farm on PastureBase Ireland (PBI) will be far more accurate.
On heavy soils, AFC should not go above 900kg DM/ha, as grazing heavy covers can be very difficult on these farms once the weather conditions start to deteriorate.
Take, for example, farms stocked at 2.5 LU/ha (or one cow per acre). At the moment, the target C/LU is 180kg DM/LU on a 21-day rotation. By 15 August, the target will be to have a C/LU of 200kg DM/LU and extend the rotation length to 25 days.
By mid-September, the grass supply should be peaking at 400-450kg DM/LU and an average farm cover of 1,000 to 1,100kg DM/ha on a rotation length of 35 days.
Small change
If you find you are behind target, a small change early on can help to keep grass in the diet for longer.
Reduce stocking rate by bringing silage ground or reseed ground back into the rotation. Remove youngstock or culls from the milking platform or use out-blocks for zero grazing, if possible.
By introducing a small amount of concentrate or silage early, you can avoid running out of grass before you had planned to close the farm.
On the other hand, as growth rates across the country have been very variable over the last number of weeks, some farms in the west and south of the country in particular may find they are ahead of target.
Now is the time to remove surplus grass from the farm, as building covers too early can lead to having pre-grazing covers well in excess of 2,500kg DM/ha. Use the opportunity to cut paddocks where grass quality is poor and ensure there is good-quality grass for the remainder of the season.
Highest covers will range from 2,000kg DM/ha to 2,500kg DM/ha in mid-September.
Farms stocked above 3 LU/ha should take advantage of higher growth rates in August and start to build covers around now. Lower-stocked farms, for example stocked at 2.5 LU/ha, have a week or so before they need to start building covers.
Fertiliser application will play a strong roll in building covers.
Pre-grazing covers
Throughout each grazing season, there is a huge emphasis on target pre-grazing covers. During the main growing season, target pre-grazing covers are between 1,350kg DM/ha and 1,500kg DM/ha. This is because during the main growing season, grass is in its reproductive state. Once grass goes past the three-leaf stage, it starts to produce a stem which will support a seed head.
Grass moves from the reproductive state to a vegetative state and no longer produces stem or a seed head.
The stem content of the plant is very high in fibre and has a lower DMD (dry matter digestibility) than the leaf content. As a result, grazing covers above 1,500kg DM/ha can have a knock-on effect on cow production at this time of year.
As we move into the latter part of the growing season, grass too is moving from its reproductive state to its vegetative state. This allows us to build covers above 1,500kg DM/ha, while maintaining quality. Achieving good graze-outs now will make it easier to hit target residuals during the last grazing.
Target a residual of 3.5cm to 4cm to ensure good-quality grass for the last rotation and into next spring.
Good grazing management will result in less dead material being carried over the winter in swards, which will have a knock-on effect on spring grass growth and quality.
Depending on the stocking rate on your farm, the target is to build AFC to between 1,000kg DM/LU and 1,200kg DM/LU for the middle of September. At this point, some of the heaviest covers on-farm will be between 2,000kg DM/ha and 2,500kg DM/ha. Research has shown that there is very little effect on winter growth once these covers are well grazed.
As weather conditions could deteriorate during September, it is very important to be flexible with your grazing plan and graze the heavy cover when it is dry. Use strip wires and backing fences if necessary to achieve a good clean-out. Like in the spring, access to paddocks will help to extend the grazing season.
Multiple access points and spur roadways give you options when getting cows in and out of paddocks.
By reducing the number of times cows travel over the same ground, you will minimise surface damage.
Your stocking rate for this period will determine what level of grass you need to build on your farm.Creating an autumn grass budget on PBI is the most accurate way to come up with a grazing plan. Average farm cover should peak in mid September (1,000kg DM/ha to 1,200kg DM/ha, depending on stocking rate).React quickly to a grass deficit by introducing a small level of supplementation to keep grass in the diet for longer. If there is a surplus of grass, cut paddocks for bales. Target cutting paddocks where grass quality needs to be corrected.Graze heavy covers only when conditions are suitable. Achieving good graze-outs will set up the farm with high-quality grass for the last rotation and into next spring.
As we move towards autumn grazing, it is worth reminding ourselves that each extra day at grass in the back end of the year is worth €1.80/cow/day.
For many, growth rates have been much lower than normal over the last number of weeks and grass has been tight, resulting in many feeding concentrates and silage.
After the rain last week and the current high soil temperatures, growth rates are predicted to rise, so growth will recover.
Where growth is slow, it is important not to allow average farm cover (AFC) fall below 500kg DM/ha.
Continue to feed concentrate and silage if necessary to reduce demand and bridge the gap. Ensure all fertiliser applications are up to date and walk the farm weekly to assess growth.
Autumn targets
The target AFC, cover per livestock unit (C/LU) and rotation length are all dependent on stocking rate. Table 1 shows a set of targets for farms stocked at 2.5 LU/ha, 3 LU/ha and 3.5 LU/ha.
The table sets out what the targets are as we move through building grass to extend the grazing season and set the farm up for more days at grass in the spring.
Although the table will work for most farms, doing an autumn grass budget for your own farm on PastureBase Ireland (PBI) will be far more accurate.
On heavy soils, AFC should not go above 900kg DM/ha, as grazing heavy covers can be very difficult on these farms once the weather conditions start to deteriorate.
Take, for example, farms stocked at 2.5 LU/ha (or one cow per acre). At the moment, the target C/LU is 180kg DM/LU on a 21-day rotation. By 15 August, the target will be to have a C/LU of 200kg DM/LU and extend the rotation length to 25 days.
By mid-September, the grass supply should be peaking at 400-450kg DM/LU and an average farm cover of 1,000 to 1,100kg DM/ha on a rotation length of 35 days.
Small change
If you find you are behind target, a small change early on can help to keep grass in the diet for longer.
Reduce stocking rate by bringing silage ground or reseed ground back into the rotation. Remove youngstock or culls from the milking platform or use out-blocks for zero grazing, if possible.
By introducing a small amount of concentrate or silage early, you can avoid running out of grass before you had planned to close the farm.
On the other hand, as growth rates across the country have been very variable over the last number of weeks, some farms in the west and south of the country in particular may find they are ahead of target.
Now is the time to remove surplus grass from the farm, as building covers too early can lead to having pre-grazing covers well in excess of 2,500kg DM/ha. Use the opportunity to cut paddocks where grass quality is poor and ensure there is good-quality grass for the remainder of the season.
Highest covers will range from 2,000kg DM/ha to 2,500kg DM/ha in mid-September.
Farms stocked above 3 LU/ha should take advantage of higher growth rates in August and start to build covers around now. Lower-stocked farms, for example stocked at 2.5 LU/ha, have a week or so before they need to start building covers.
Fertiliser application will play a strong roll in building covers.
Pre-grazing covers
Throughout each grazing season, there is a huge emphasis on target pre-grazing covers. During the main growing season, target pre-grazing covers are between 1,350kg DM/ha and 1,500kg DM/ha. This is because during the main growing season, grass is in its reproductive state. Once grass goes past the three-leaf stage, it starts to produce a stem which will support a seed head.
Grass moves from the reproductive state to a vegetative state and no longer produces stem or a seed head.
The stem content of the plant is very high in fibre and has a lower DMD (dry matter digestibility) than the leaf content. As a result, grazing covers above 1,500kg DM/ha can have a knock-on effect on cow production at this time of year.
As we move into the latter part of the growing season, grass too is moving from its reproductive state to its vegetative state. This allows us to build covers above 1,500kg DM/ha, while maintaining quality. Achieving good graze-outs now will make it easier to hit target residuals during the last grazing.
Target a residual of 3.5cm to 4cm to ensure good-quality grass for the last rotation and into next spring.
Good grazing management will result in less dead material being carried over the winter in swards, which will have a knock-on effect on spring grass growth and quality.
Depending on the stocking rate on your farm, the target is to build AFC to between 1,000kg DM/LU and 1,200kg DM/LU for the middle of September. At this point, some of the heaviest covers on-farm will be between 2,000kg DM/ha and 2,500kg DM/ha. Research has shown that there is very little effect on winter growth once these covers are well grazed.
As weather conditions could deteriorate during September, it is very important to be flexible with your grazing plan and graze the heavy cover when it is dry. Use strip wires and backing fences if necessary to achieve a good clean-out. Like in the spring, access to paddocks will help to extend the grazing season.
Multiple access points and spur roadways give you options when getting cows in and out of paddocks.
By reducing the number of times cows travel over the same ground, you will minimise surface damage.
Your stocking rate for this period will determine what level of grass you need to build on your farm.Creating an autumn grass budget on PBI is the most accurate way to come up with a grazing plan. Average farm cover should peak in mid September (1,000kg DM/ha to 1,200kg DM/ha, depending on stocking rate).React quickly to a grass deficit by introducing a small level of supplementation to keep grass in the diet for longer. If there is a surplus of grass, cut paddocks for bales. Target cutting paddocks where grass quality needs to be corrected.Graze heavy covers only when conditions are suitable. Achieving good graze-outs will set up the farm with high-quality grass for the last rotation and into next spring. 
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