Keeping quality grass in front of cows has been a challenge over the last fortnight. A combination of very high grass growth rates at the same time as grass is going to seed has led to a decline in quality. May was a good month for grass growth, beating the five-year average. However, growth started to decline towards the end of the month, as is normal. The decline in 2019 was probably exacerbated on some farms by rising soil moisture deficits and some harsh drying conditions.
And then things changed with a bang. Widespread heavy rain and mild weather in late May and early June has created another spike in growth. This spike in growth is happening at the same time as grass is going to seed. Stephen Connolly, who is running the Irish Farmers Journal/Macra Skillnet grass courses, explained this at a course in Limerick last week.
Excellent clean outs are being achieved where grass quality is good and pre-grazing yield is not too strong.
“At this time of year the priority for the grass plant is to produce seeds so that it can reproduce. The first sign of seed heads is more stem in the sward as it needs a strong and tall stem to support the seed head. Grass that was poorly grazed in the last few rotations or that is too strong for grazing now will have a lot more stem in it and this will cause a drop in milk yield and protein per cent if cows are asked to graze it,” Stephen says.
So the priority over the next few weeks is to minimise the amount of stem that the cows have to graze by diverting poor-quality covers to bale silage and leaving leafier covers for grazing. These bales can then be fed out next autumn and spring to supplement cows at grass. A farmer on the course asked if that type of grass makes good silage, why can’t it be grazed?
Stephen suggested that the silage from strong covers will have a DMD in the mid-70s, whereas good-quality grass will have a DMD in the mid-80s.
Good clean outs from last week on the O'Reilly farm .
“The other thing to consider when looking at grass is intakes. Stemmy grass takes longer to digest and pass through the cow. This means she won’t be as hungry as her rumen will be fuller so intakes drop. Without high intakes of good-quality grass, she won’t have enough energy to produce the same amount of milk so yield will drop and so too will protein per cent as this is an indicator of energy intake,” Stephen says.
He said the reverse is true when grass quality is really good. When grazing reseeds or aftergrass, cows tend to go through them a lot faster. Another farmer asked if this is because we over-estimate the covers in these swards? Stephen said that while the dry matter is probably a percentage or two lower in these types of covers, the main reason cows go through them faster is because they are good quality and highly digestible so their intakes increase and they tend to milk more on these type of covers.
Reseeds
The host farmers for one of the courses in Limerick, Michael and Brian O’Reilly from Caherconlish, are milking 420 cows on a 100ha milking platform. A few paddocks close to the yard have been reseeded over the last few weeks. A couple of paddocks were sown on 29 March, with another paddock sown later. The varieties used were Abergain, Aberchoice and 0.5kg of white clover.
The paddock on the O'Reilly farm where the cows were last night. The section to the right is going for bales.
As we were walking into the reseeded field, Michael was telling me they were going to give it a post-emergence spray later that day and then let calves into it next week. The plan had changed considerably by the time we walked out of the field. The cover was cut and weighed at 1,080kg/ha. The group concluded that the field needed to be grazed as soon as possible and should really have been grazed before now, to allow the new plants to tiller out.
It was felt that it would be better to graze the field first and then spray it after grazing. Brian O’Reilly said the spray they were using was the clover-safe spray Clovex, which states that 14 days should elapse between spraying and grazing. Dock seedlings weren’t seen in the field but there was a good few nettles in places and plenty of chickweed throughout. The other thing the group said was that calves would be lost in it – it had to be grazed by cows.
As was the case with a lot of farmers, grass got ahead of them last week, despite the fact that they’re measuring grass every four or five days.
This field of Abergain and Aberchoice was reseeded on 29 March and will be grazed by the cows.
At their last measurement, the cover per cow was 191kg with a growth rate of 68 and a demand of 72. The night before the meeting the cows were grazing a cover of 2,500kg/ha. The O’Reillys recognised that this was too strong so skipped what was left in the field and moved to a better cover. Brian says that in hindsight, setting the cover at 191kg/cow at the last walk was too high, considering growth rate was increasing.
Two more paddocks were skipped for short-term silage after the grass walk. This brought down the average farm cover to 164kg/cow with a demand of 67. The growth rate between that walk and the previous walk was 88kg/day. The grass measurement was completed on Pasturebase and a big emphasis was placed on the cover per cow figure, the wedge and the demand. Stephen says the cover per cow should be between 160kg and 180kg per cow at this time of year. He suggests it should be at the lower end of the scale when growth is looking good, and at the higher end of the scale when growth is more uncertain, like it is in some places now with colder than normal temperatures.
“Look at the wedge and see what the cover is on the highest paddock. The target is 1,500kg. Sometimes the second or third paddock could be less than 1,500kg but in that case count how many days it will be before the cows are there. If a paddock has 1,200kg on it and it’s three days away from being grazed and the farm is growing an average of 80kg the chances are that paddock is growing 100kg/day so it will be fine. The other thing I always look at is the predicted wedge to see what it’ll be like next week. That helps to verify your decisions,” Stephen says.
Pre-mowing
There was consensus that topping to correct residuals and reduce stem in the new sward is not a good policy. The main reasons given by the farmers on the course was that it reduces growth rate. One farmer gave an example. He said he split a paddock in half and the cows grazed one half during the day. He topped that paddock as soon as the cows left for evening milking and pre-mowed the other half of the field where the cows were going that night. The side of the field that was topped had a few hundred kilos less grass per hectare compared to the pre-mowed side at the next grazing.
Stephen Connolly getting grass figures off the course participants on the O'Reilly farm at Caherconlish, Co Limerick.
However, Stephen pointed out that while pre-mowing might be good for the grass, it’s not always good for the cow as she is potentially being made to eat more stemmy grass. He said that pre-mowing shouldn’t be used to correct poor residuals.
The Irish Farmers Journal/Macra Skillnet courses are taking place once a month on 10 farms across the country. A number of one-off and advanced courses are being organised also. Teagasc is also running courses on grassland management, with 48 courses being run across the country. To enrol in these courses, contact Stephen Connolly from the Irish Farmers Journal on 087 669 6490 or your local Teagasc office for the Teagasc courses.
Key points
Walk the farm every five or six days and make decisions based on what you find.The target is to set the average farm cover at between 160 and 180kg/cow.Match demand with expected growth rate for the week ahead.If paddocks need to be skipped, identify poor quality and stemmy paddocks and skip these. Some farmers have ground taken out for silage and are struggling to find an opportunity to cut it. Colder nights are likely to cause a reduction in growth rates over the coming few days.Continue to spread between 0.5 and one unit per day of nitrogen on the grazing platform.
Keeping quality grass in front of cows has been a challenge over the last fortnight. A combination of very high grass growth rates at the same time as grass is going to seed has led to a decline in quality. May was a good month for grass growth, beating the five-year average. However, growth started to decline towards the end of the month, as is normal. The decline in 2019 was probably exacerbated on some farms by rising soil moisture deficits and some harsh drying conditions.
And then things changed with a bang. Widespread heavy rain and mild weather in late May and early June has created another spike in growth. This spike in growth is happening at the same time as grass is going to seed. Stephen Connolly, who is running the Irish Farmers Journal/Macra Skillnet grass courses, explained this at a course in Limerick last week.
Excellent clean outs are being achieved where grass quality is good and pre-grazing yield is not too strong.
“At this time of year the priority for the grass plant is to produce seeds so that it can reproduce. The first sign of seed heads is more stem in the sward as it needs a strong and tall stem to support the seed head. Grass that was poorly grazed in the last few rotations or that is too strong for grazing now will have a lot more stem in it and this will cause a drop in milk yield and protein per cent if cows are asked to graze it,” Stephen says.
So the priority over the next few weeks is to minimise the amount of stem that the cows have to graze by diverting poor-quality covers to bale silage and leaving leafier covers for grazing. These bales can then be fed out next autumn and spring to supplement cows at grass. A farmer on the course asked if that type of grass makes good silage, why can’t it be grazed?
Stephen suggested that the silage from strong covers will have a DMD in the mid-70s, whereas good-quality grass will have a DMD in the mid-80s.
Good clean outs from last week on the O'Reilly farm .
“The other thing to consider when looking at grass is intakes. Stemmy grass takes longer to digest and pass through the cow. This means she won’t be as hungry as her rumen will be fuller so intakes drop. Without high intakes of good-quality grass, she won’t have enough energy to produce the same amount of milk so yield will drop and so too will protein per cent as this is an indicator of energy intake,” Stephen says.
He said the reverse is true when grass quality is really good. When grazing reseeds or aftergrass, cows tend to go through them a lot faster. Another farmer asked if this is because we over-estimate the covers in these swards? Stephen said that while the dry matter is probably a percentage or two lower in these types of covers, the main reason cows go through them faster is because they are good quality and highly digestible so their intakes increase and they tend to milk more on these type of covers.
Reseeds
The host farmers for one of the courses in Limerick, Michael and Brian O’Reilly from Caherconlish, are milking 420 cows on a 100ha milking platform. A few paddocks close to the yard have been reseeded over the last few weeks. A couple of paddocks were sown on 29 March, with another paddock sown later. The varieties used were Abergain, Aberchoice and 0.5kg of white clover.
The paddock on the O'Reilly farm where the cows were last night. The section to the right is going for bales.
As we were walking into the reseeded field, Michael was telling me they were going to give it a post-emergence spray later that day and then let calves into it next week. The plan had changed considerably by the time we walked out of the field. The cover was cut and weighed at 1,080kg/ha. The group concluded that the field needed to be grazed as soon as possible and should really have been grazed before now, to allow the new plants to tiller out.
It was felt that it would be better to graze the field first and then spray it after grazing. Brian O’Reilly said the spray they were using was the clover-safe spray Clovex, which states that 14 days should elapse between spraying and grazing. Dock seedlings weren’t seen in the field but there was a good few nettles in places and plenty of chickweed throughout. The other thing the group said was that calves would be lost in it – it had to be grazed by cows.
As was the case with a lot of farmers, grass got ahead of them last week, despite the fact that they’re measuring grass every four or five days.
This field of Abergain and Aberchoice was reseeded on 29 March and will be grazed by the cows.
At their last measurement, the cover per cow was 191kg with a growth rate of 68 and a demand of 72. The night before the meeting the cows were grazing a cover of 2,500kg/ha. The O’Reillys recognised that this was too strong so skipped what was left in the field and moved to a better cover. Brian says that in hindsight, setting the cover at 191kg/cow at the last walk was too high, considering growth rate was increasing.
Two more paddocks were skipped for short-term silage after the grass walk. This brought down the average farm cover to 164kg/cow with a demand of 67. The growth rate between that walk and the previous walk was 88kg/day. The grass measurement was completed on Pasturebase and a big emphasis was placed on the cover per cow figure, the wedge and the demand. Stephen says the cover per cow should be between 160kg and 180kg per cow at this time of year. He suggests it should be at the lower end of the scale when growth is looking good, and at the higher end of the scale when growth is more uncertain, like it is in some places now with colder than normal temperatures.
“Look at the wedge and see what the cover is on the highest paddock. The target is 1,500kg. Sometimes the second or third paddock could be less than 1,500kg but in that case count how many days it will be before the cows are there. If a paddock has 1,200kg on it and it’s three days away from being grazed and the farm is growing an average of 80kg the chances are that paddock is growing 100kg/day so it will be fine. The other thing I always look at is the predicted wedge to see what it’ll be like next week. That helps to verify your decisions,” Stephen says.
Pre-mowing
There was consensus that topping to correct residuals and reduce stem in the new sward is not a good policy. The main reasons given by the farmers on the course was that it reduces growth rate. One farmer gave an example. He said he split a paddock in half and the cows grazed one half during the day. He topped that paddock as soon as the cows left for evening milking and pre-mowed the other half of the field where the cows were going that night. The side of the field that was topped had a few hundred kilos less grass per hectare compared to the pre-mowed side at the next grazing.
Stephen Connolly getting grass figures off the course participants on the O'Reilly farm at Caherconlish, Co Limerick.
However, Stephen pointed out that while pre-mowing might be good for the grass, it’s not always good for the cow as she is potentially being made to eat more stemmy grass. He said that pre-mowing shouldn’t be used to correct poor residuals.
The Irish Farmers Journal/Macra Skillnet courses are taking place once a month on 10 farms across the country. A number of one-off and advanced courses are being organised also. Teagasc is also running courses on grassland management, with 48 courses being run across the country. To enrol in these courses, contact Stephen Connolly from the Irish Farmers Journal on 087 669 6490 or your local Teagasc office for the Teagasc courses.
Key points
Walk the farm every five or six days and make decisions based on what you find.The target is to set the average farm cover at between 160 and 180kg/cow.Match demand with expected growth rate for the week ahead.If paddocks need to be skipped, identify poor quality and stemmy paddocks and skip these. Some farmers have ground taken out for silage and are struggling to find an opportunity to cut it. Colder nights are likely to cause a reduction in growth rates over the coming few days.Continue to spread between 0.5 and one unit per day of nitrogen on the grazing platform. 
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