There is strong interest among farmers in the potential role of companion or mixed species swards, with early experimentation in this area typically yielding positive results from the perspective of increasing lamb performance. The big question with these swards is their persistency. As such, there is a lot of interest in the trials taking place in Teagasc Mellows Campus Athenry.
Philip Creighton, Teagasc Atherny \ CJ Nash
The trials taking place under the stewardship of Philip Creighton aim to examine the potential of grass-white clover swards and other alternative forages and in particular their ability to support increased output levels. The perennial ryegrass-clover swards and herbal leys including perennial ryegrass and chicory/plantain are being put to the test in a commercially focused production enterprise and as such are being robustly tested.
Grass-white clover
The first component of the trial is evaluating grass-white clover swards at two levels of artificial nitrogen input and medium (11 ewes/ha or 2.2LU/ha) and high (13 ewes/ha or 2.6LU/ha) stocking rates. The two nitrogen input levels on the grass-white clover swards are 145kg N/ha and 90kg N/ha while for comparison purposes a grass-only sward with a nitrogen input of 145kg N/ha was also included.
The persistency of white clover (pictured), red clover, chicory and plantain is one of the greatest challenges undermining the value of the alternative forage crops.
The average sward dry matter yield was measured since the swards were set up in 2017, ahead of the trial starting in 2018. The volume of grass grown under each treatment is detailed in Figure 1. As can be readily seen there was no major difference between the three treatments in the volume of dry matter produced.
Commenting on results to date, Philip said: “for me the fact that the lower chemical nitrogen treatment is holding its own is important in terms of reducing costs of production but more importantly there are significant environmental benefits without having to forgo output levels to any great extent.”
Lamb performance
The grass-white clover swards are also supporting higher lamb performance with lambs grazing these swards returning an average figure of 201 days to slaughter compared to 208 for the grass-only sward. This may seem a small number on an individual basis but on a significant number of lambs it can have a big influence. Philip thinks there is potential to bring about greater improvement in this area if the persistency of swards can be addressed and methods of establishment refined.
Alternative forages trial in Mellows Campus Athenry.
Table 1 delves deeper into the analysis and looks at the lamb drafting rate to-date compared to the corresponding period in 2019.
There is a higher drafting rate in the perennial ryegrass and white clover swards in 2020 and Philip says this is resulting from incorporating white clover into swards. The percentage of clover was also boosted by the dry spring providing ideal conditions to get swards grazed out, thereby allowing more light to penetrate down to the base of the sward and promote clover development.
When analysed on a stocking rate basis, the high stocking rate treatment has a lower drafting rate in 2020. This is partly due to high rainfall stifling lamb performance but drafting rates have regained some of this lost ground in recent weeks.
There is a word of caution at this stage of the trial on if the lower nitrogen application grass-white clover swards are capable of supporting high stocking rates of 13 ewes/ha. The possible difficulties emerging are if these low nitrogen input swards can sustain a high stocking rate at the shoulders of the grazing season – namely are they capable of satisfying a rapid increase in demand from ewes and lambs in spring and are they equipped to build a reserve of grass in autumn? Philip says there will be greater focus on this area going forward in the trial to establish workable blueprints.
Alternative forages
The second component of the trial evaluating alternative forages in combination with perennial ryegrass is specifically looking at if these forages have the ability to increase animal intake, performance and output in pasture-based sheep production systems. Lisa McGrane, a Teagasc and UCD Walsh Scholar, is working on the trial which also commenced in 2018 following the establishment of trial plots in 2017.
Lisa McGrane, Teagasc and UCD Walsh Scholar working with the trial.
There are five treatments under investigation – perennial ryegrass only; perennial ryegrass plus white clover; perennial ryegrass plus grazing tolerant red clover; perennial ryegrass plus plantain; and perennial ryegrass plus chicory.
Alternative forages trial in Mellows Campus Athenry.
Philip says that in general the inclusion of a forage alongside perennial ryegrass has resulted in an increase in the yield of dry matter produced. This is reflected in Figure 2, which details the dry matter yield in 2020 up to the end of September. The yield of the perennial ryegrass and red clover sward is lower than expected and Philip explains it is likely that this has been influenced by reseeding possibly causing a lag phase in growth.
Persistency challenges
Figure 2 fails to show that the dry matter yield in the combination swards in 2020 is being boosted by a significant amount of reseeding being carried out. Figures 3 and 4 can be used to explain this. Figure 3 details the sward forage content percentage of the initial swards established in 2017 / 2018 in 2018, 2019 and 2020.
It is clear from the graph that the percentage of chicory and plantain, in particular, has reduced majorly in less than three years, confirming reported persistency issues. The data also shows the higher dry matter yield in the second half of the year and this is what is directly feeding into improved animal performance.
Figure 4 details the sward forage content percentage including plots reseeded in 2019 and 2020. It is immediately apparent that to maintain a high sward forage content in such a system as these crops are being trialled under, a regular reseeding programme will be required. Given the costs of reseeding, this raises significant questions about the feasibility of such an approach. Altering the production system may have a role and this is discussed in further detail later.
Lamb performance
There is no doubt where the forages are present they can sustain higher lamb performance. Table 2 details the lamb drafting rate to the end of September and compares it to the corresponding period in 2019.
Performance across the different sward types was not too dissimilar in 2019, such was the reduction in the content of herbs and clovers in the swards.
In contrast, the 2020 performance shows a clear difference in performance between the perennial ryegrass only swards and the other four treatments. This is owing to the increased content of herbs and clovers in these swards in 2020. This is reflected in the drafting percentage to the end of September and also to the end of October.
Lambs grazing the companion swards with herb and clover additions are achieving higher performance than the perennial ryegrass only sward.
Future focus areas
As persistency issues are the greatest challenge, the focus of future research is to try to alter various aspects of the trial to see if this can promote improvements in this area. This includes refining establishment methods and timing, grazing management, weed control, seeding rates and stocking rates.
There is a huge job of work in setting up the infrastructure to put these parameters to the test, not to mention the volume of data that will need to be recorded.
Future research will focus on grazing strategies and assess if persistency can be improved through this avenue.
On the establishment front, four reseeding methods are being put to the test – conventional sowing (including ploughing), direct drilling, discing and power harrowing. Across four forage mixtures, more than 60 plots are needed to put this aspect to the test.
Philip says weed control was a significant issue at the outset but it has improved since they started using a stale seedbed. He says that once the crop has the optimum opportunity to establish, it has generally been able to compete with and supress weed growth.
Post grazing sward heights
A contributor to poor persistency is likely to be the manner in which swards are grazed. The target post-grazing heights for perennial ryegrass are designed to maximise grass quality but this may be damaging to the persistency of the herbal leys and clover.
A total of 36 grazing plots have been established, allowing three post-grazing sward heights of 4cm, 4.75cm and 5.5cm to be tested across the five treatments. The big question that has also to be answered in this regard is that if a higher post-grazing sward height enhances the persistency of the herbal leys and clover, will it have a detrimental effect on the quality of ryegrass and undo any of the advantages achieved.
The other major component of future work is tweaking seeding rates. There is a school of thought that sheep swards are generally dense in nature and by reducing the percentage of ryegrass and increasing herb and clover seeding rates it will allow these to compete with greater intensity and potentially remain for longer in the sward.
Plantain in a grass sward.
Clover seeding rates will be trialled at high (7kg/ha), medium (5kg/ha) and low (2.5kg/ha) while herb seeding rates will be trialled at high (5kg/ha), medium (3.5kg/ha) and low (2kg/ha).
The overall seeding rate is being set at 25kg/ha with the balance in each treatment made up of a tetraploid or diploid perennial ryegrass variety. This requires a total of 72 plots, all of which are grazed to deliver as close to normal grazing conditions as possible.
Emissions investigation
An investigation will also begin in 2021 to determine if herbal or clover leys have beneficial properties in terms of greenhouse gas emissions compared to conventional perennial ryegrass swards. This work will be completed as part of the trial led by Fiona McGovern whereby intake profiles and emissions are closely monitored through the use of portable accumulation chambers.
There is strong interest among farmers in the potential role of companion or mixed species swards, with early experimentation in this area typically yielding positive results from the perspective of increasing lamb performance. The big question with these swards is their persistency. As such, there is a lot of interest in the trials taking place in Teagasc Mellows Campus Athenry.
Philip Creighton, Teagasc Atherny \ CJ Nash
The trials taking place under the stewardship of Philip Creighton aim to examine the potential of grass-white clover swards and other alternative forages and in particular their ability to support increased output levels. The perennial ryegrass-clover swards and herbal leys including perennial ryegrass and chicory/plantain are being put to the test in a commercially focused production enterprise and as such are being robustly tested.
Grass-white clover
The first component of the trial is evaluating grass-white clover swards at two levels of artificial nitrogen input and medium (11 ewes/ha or 2.2LU/ha) and high (13 ewes/ha or 2.6LU/ha) stocking rates. The two nitrogen input levels on the grass-white clover swards are 145kg N/ha and 90kg N/ha while for comparison purposes a grass-only sward with a nitrogen input of 145kg N/ha was also included.
The persistency of white clover (pictured), red clover, chicory and plantain is one of the greatest challenges undermining the value of the alternative forage crops.
The average sward dry matter yield was measured since the swards were set up in 2017, ahead of the trial starting in 2018. The volume of grass grown under each treatment is detailed in Figure 1. As can be readily seen there was no major difference between the three treatments in the volume of dry matter produced.
Commenting on results to date, Philip said: “for me the fact that the lower chemical nitrogen treatment is holding its own is important in terms of reducing costs of production but more importantly there are significant environmental benefits without having to forgo output levels to any great extent.”
Lamb performance
The grass-white clover swards are also supporting higher lamb performance with lambs grazing these swards returning an average figure of 201 days to slaughter compared to 208 for the grass-only sward. This may seem a small number on an individual basis but on a significant number of lambs it can have a big influence. Philip thinks there is potential to bring about greater improvement in this area if the persistency of swards can be addressed and methods of establishment refined.
Alternative forages trial in Mellows Campus Athenry.
Table 1 delves deeper into the analysis and looks at the lamb drafting rate to-date compared to the corresponding period in 2019.
There is a higher drafting rate in the perennial ryegrass and white clover swards in 2020 and Philip says this is resulting from incorporating white clover into swards. The percentage of clover was also boosted by the dry spring providing ideal conditions to get swards grazed out, thereby allowing more light to penetrate down to the base of the sward and promote clover development.
When analysed on a stocking rate basis, the high stocking rate treatment has a lower drafting rate in 2020. This is partly due to high rainfall stifling lamb performance but drafting rates have regained some of this lost ground in recent weeks.
There is a word of caution at this stage of the trial on if the lower nitrogen application grass-white clover swards are capable of supporting high stocking rates of 13 ewes/ha. The possible difficulties emerging are if these low nitrogen input swards can sustain a high stocking rate at the shoulders of the grazing season – namely are they capable of satisfying a rapid increase in demand from ewes and lambs in spring and are they equipped to build a reserve of grass in autumn? Philip says there will be greater focus on this area going forward in the trial to establish workable blueprints.
Alternative forages
The second component of the trial evaluating alternative forages in combination with perennial ryegrass is specifically looking at if these forages have the ability to increase animal intake, performance and output in pasture-based sheep production systems. Lisa McGrane, a Teagasc and UCD Walsh Scholar, is working on the trial which also commenced in 2018 following the establishment of trial plots in 2017.
Lisa McGrane, Teagasc and UCD Walsh Scholar working with the trial.
There are five treatments under investigation – perennial ryegrass only; perennial ryegrass plus white clover; perennial ryegrass plus grazing tolerant red clover; perennial ryegrass plus plantain; and perennial ryegrass plus chicory.
Alternative forages trial in Mellows Campus Athenry.
Philip says that in general the inclusion of a forage alongside perennial ryegrass has resulted in an increase in the yield of dry matter produced. This is reflected in Figure 2, which details the dry matter yield in 2020 up to the end of September. The yield of the perennial ryegrass and red clover sward is lower than expected and Philip explains it is likely that this has been influenced by reseeding possibly causing a lag phase in growth.
Persistency challenges
Figure 2 fails to show that the dry matter yield in the combination swards in 2020 is being boosted by a significant amount of reseeding being carried out. Figures 3 and 4 can be used to explain this. Figure 3 details the sward forage content percentage of the initial swards established in 2017 / 2018 in 2018, 2019 and 2020.
It is clear from the graph that the percentage of chicory and plantain, in particular, has reduced majorly in less than three years, confirming reported persistency issues. The data also shows the higher dry matter yield in the second half of the year and this is what is directly feeding into improved animal performance.
Figure 4 details the sward forage content percentage including plots reseeded in 2019 and 2020. It is immediately apparent that to maintain a high sward forage content in such a system as these crops are being trialled under, a regular reseeding programme will be required. Given the costs of reseeding, this raises significant questions about the feasibility of such an approach. Altering the production system may have a role and this is discussed in further detail later.
Lamb performance
There is no doubt where the forages are present they can sustain higher lamb performance. Table 2 details the lamb drafting rate to the end of September and compares it to the corresponding period in 2019.
Performance across the different sward types was not too dissimilar in 2019, such was the reduction in the content of herbs and clovers in the swards.
In contrast, the 2020 performance shows a clear difference in performance between the perennial ryegrass only swards and the other four treatments. This is owing to the increased content of herbs and clovers in these swards in 2020. This is reflected in the drafting percentage to the end of September and also to the end of October.
Lambs grazing the companion swards with herb and clover additions are achieving higher performance than the perennial ryegrass only sward.
Future focus areas
As persistency issues are the greatest challenge, the focus of future research is to try to alter various aspects of the trial to see if this can promote improvements in this area. This includes refining establishment methods and timing, grazing management, weed control, seeding rates and stocking rates.
There is a huge job of work in setting up the infrastructure to put these parameters to the test, not to mention the volume of data that will need to be recorded.
Future research will focus on grazing strategies and assess if persistency can be improved through this avenue.
On the establishment front, four reseeding methods are being put to the test – conventional sowing (including ploughing), direct drilling, discing and power harrowing. Across four forage mixtures, more than 60 plots are needed to put this aspect to the test.
Philip says weed control was a significant issue at the outset but it has improved since they started using a stale seedbed. He says that once the crop has the optimum opportunity to establish, it has generally been able to compete with and supress weed growth.
Post grazing sward heights
A contributor to poor persistency is likely to be the manner in which swards are grazed. The target post-grazing heights for perennial ryegrass are designed to maximise grass quality but this may be damaging to the persistency of the herbal leys and clover.
A total of 36 grazing plots have been established, allowing three post-grazing sward heights of 4cm, 4.75cm and 5.5cm to be tested across the five treatments. The big question that has also to be answered in this regard is that if a higher post-grazing sward height enhances the persistency of the herbal leys and clover, will it have a detrimental effect on the quality of ryegrass and undo any of the advantages achieved.
The other major component of future work is tweaking seeding rates. There is a school of thought that sheep swards are generally dense in nature and by reducing the percentage of ryegrass and increasing herb and clover seeding rates it will allow these to compete with greater intensity and potentially remain for longer in the sward.
Plantain in a grass sward.
Clover seeding rates will be trialled at high (7kg/ha), medium (5kg/ha) and low (2.5kg/ha) while herb seeding rates will be trialled at high (5kg/ha), medium (3.5kg/ha) and low (2kg/ha).
The overall seeding rate is being set at 25kg/ha with the balance in each treatment made up of a tetraploid or diploid perennial ryegrass variety. This requires a total of 72 plots, all of which are grazed to deliver as close to normal grazing conditions as possible.
Emissions investigation
An investigation will also begin in 2021 to determine if herbal or clover leys have beneficial properties in terms of greenhouse gas emissions compared to conventional perennial ryegrass swards. This work will be completed as part of the trial led by Fiona McGovern whereby intake profiles and emissions are closely monitored through the use of portable accumulation chambers.
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