May is arguably the most important month during the grazing season. Grass enters the period of peak growth and keeping swards under control becomes extremely difficult.
Towards the end of the month, sward quality starts to deteriorate as grass begins to head out. At this point, the amount of stem in swards increases, whereas digestible leaf content falls.
If cattle continue to graze headed out swards over the summer, milk yield and liveweight gain will suffer.
Take a group of 20 high genetic merit steers gaining 1.1kg/day grazing good-quality swards during May. Grass heads out around 1 June and no action is taken to rectify sward quality.
Weight gain is subsequently reduced by 0.2kg/day. Over the next 100 days, which takes cattle into September, the group has potentially lost 400kg of liveweight.
Valuing cattle at 300p/kg if sold live, the drop in performance costs the farmer £1,200. This would more than cover the time spent moving electric fences, topping or taking out surplus grass.
Challenging
Trying to keep on top of grass quality from mid-May to early June is hard work. It can also be time-consuming and frustrating if the weather is not on your side.
There is no one single step that will maintain grass quality, but rather a combination of factors, some of which are outlined as follows.
Shorten the grazing rotation
The first step is shortening the grazing rotation to between 12 and 15 days. Moving cattle around the grazing block faster means animals go in to lower grass covers.
This makes it much easier to graze swards down fully, improving grass quality in the next rotation.
To shorten the rotation, the easiest option is reducing the size of the grazing area by closing off paddocks for silage or reseeding.
Increasing the size of a grazing group is also an option, but it comes with plenty of drawbacks.
If a wet spell materialises, more cattle increases the risk of poaching. Also, when grass growth slows, cattle have to be removed again which is not always straightforward.
Don’t force cattle to clean out heavy covers
If cattle are turned into paddocks where grass covers are too strong, trying to graze down to a residual of 4cm is extremely hard to do.
It also does more harm than good. First off, holding cattle in a paddock of strong grass just to graze it down tight means the covers in the paddocks ahead gets even stronger.
As a result, grass quality in the next two to three paddocks gets lower and lower by the day.
Forcing cattle to graze out heavy covers tight to the ground means animals are predominantly eating fibre, not digestible leaf, and performance will suffer.
It is much better to graze for 24 to 48 hours, then move cattle on. Either top the rejected grass, or use stock such as dry autumn-calving cows to clean out covers.
Are there benefits from pre-mowing swards?
As grass growth increases, some farmers prefer pre-mowing to control swards and leave a clean residual for regrowth instead of topping.
Once grass is mowed, it will start wilting which increases dry matter intakes, boosting liveweight gain. However, it is heavily dependent on weather and ground conditions for mowing.
It’s not a long-term strategy for controlling grass. But when done properly, pre-mowing can help cattle move through swards faster and improve grass quality.
Never pre-mow swards that have ragwort present. Once mowed, ragwort becomes much more palatable to cattle. But it remains extremely poisonous.
Skipping paddocks for silage
It takes confidence to take paddocks out of the grazing rotation for silage. Farmers often fear they will run short of grass.
But by walking swards every week in May, it is easier to see which paddocks can be skipped and cut for silage.
The key thing to remember is that once a paddock has been skipped or closed up, you should cut these swards for silage at the first opportunity.
Don’t hold off mowing grass just to let swards bulk out more, or to justify getting the contractor in with the baler.
Mowing early leaves a green aftermath that is quick to regrow and come back in to the rotation again. Delaying cutting will only slow regrowth, increasing the risk of running out of grass.
Apply fertiliser on a little and often approach
As grass starts to get ahead of cattle, there is a temptation to stop applying fertiliser in May.
However, the lack of nitrogen is more likely to cause grass to head out much earlier than swards which receive fertiliser this month.
Applying 15 to 20 units/acre of nitrogen, on a little and often approach, will help delay swards from heading out.
It will also maximise grass yields during the period of peak growth. Where surplus grass is cut for silage, it will boost fodder reserves for winter.
On paddocks carrying lactating cows, stick to using a nitrogen-only fertiliser such as CAN or protected urea. Avoid high-potash fertilisers as they increase the risk of grass tetany.
Applying smaller quantities of nitrogen fits in with a shorter grazing rotation, helping to avoid issues such as nitrate poisoning in grazing animals.
Splitting paddocks into smaller areas
Use electric fencing to temporarily split paddocks into smaller grazing allocations that last 24 to 48 hours.
Smaller paddocks offer greater control over sward quality, making it easier to skip paddocks and improve cleanout.
Smaller paddocks does mean moving animals more often. But animals quickly become accustomed to frequent handling and will happily move to fresh grass.
Electric fencing can be used to control grazing areas and improve sward quality.
Water provision does becomes a problem when splitting paddocks, but there will be ways of working around this issue.
If strip grazing cattle, make sure to give a big enough allocation and move the fence around the same time every day.
There are plenty of farmers who prefer set-stocking grazing ground for a variety of reasons.
However, even with set-stocking, there are still ways to control grass quality so that cattle have access to swards with plenty of digestible leaf.
One option is to top the field in stages every week. For example, start off by topping one-third of the field on week one.
Top the middle third on week two, then top the last third during the following week.
The idea is that grass will grow in a more controlled manner with fresh regrowth coming every week.
Cattle will be more inclined to graze on the areas with shorter covers after topping, rather than the areas where grass has headed out and is mainly stem.
Read more
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May is arguably the most important month during the grazing season. Grass enters the period of peak growth and keeping swards under control becomes extremely difficult.
Towards the end of the month, sward quality starts to deteriorate as grass begins to head out. At this point, the amount of stem in swards increases, whereas digestible leaf content falls.
If cattle continue to graze headed out swards over the summer, milk yield and liveweight gain will suffer.
Take a group of 20 high genetic merit steers gaining 1.1kg/day grazing good-quality swards during May. Grass heads out around 1 June and no action is taken to rectify sward quality.
Weight gain is subsequently reduced by 0.2kg/day. Over the next 100 days, which takes cattle into September, the group has potentially lost 400kg of liveweight.
Valuing cattle at 300p/kg if sold live, the drop in performance costs the farmer £1,200. This would more than cover the time spent moving electric fences, topping or taking out surplus grass.
Challenging
Trying to keep on top of grass quality from mid-May to early June is hard work. It can also be time-consuming and frustrating if the weather is not on your side.
There is no one single step that will maintain grass quality, but rather a combination of factors, some of which are outlined as follows.
Shorten the grazing rotation
The first step is shortening the grazing rotation to between 12 and 15 days. Moving cattle around the grazing block faster means animals go in to lower grass covers.
This makes it much easier to graze swards down fully, improving grass quality in the next rotation.
To shorten the rotation, the easiest option is reducing the size of the grazing area by closing off paddocks for silage or reseeding.
Increasing the size of a grazing group is also an option, but it comes with plenty of drawbacks.
If a wet spell materialises, more cattle increases the risk of poaching. Also, when grass growth slows, cattle have to be removed again which is not always straightforward.
Don’t force cattle to clean out heavy covers
If cattle are turned into paddocks where grass covers are too strong, trying to graze down to a residual of 4cm is extremely hard to do.
It also does more harm than good. First off, holding cattle in a paddock of strong grass just to graze it down tight means the covers in the paddocks ahead gets even stronger.
As a result, grass quality in the next two to three paddocks gets lower and lower by the day.
Forcing cattle to graze out heavy covers tight to the ground means animals are predominantly eating fibre, not digestible leaf, and performance will suffer.
It is much better to graze for 24 to 48 hours, then move cattle on. Either top the rejected grass, or use stock such as dry autumn-calving cows to clean out covers.
Are there benefits from pre-mowing swards?
As grass growth increases, some farmers prefer pre-mowing to control swards and leave a clean residual for regrowth instead of topping.
Once grass is mowed, it will start wilting which increases dry matter intakes, boosting liveweight gain. However, it is heavily dependent on weather and ground conditions for mowing.
It’s not a long-term strategy for controlling grass. But when done properly, pre-mowing can help cattle move through swards faster and improve grass quality.
Never pre-mow swards that have ragwort present. Once mowed, ragwort becomes much more palatable to cattle. But it remains extremely poisonous.
Skipping paddocks for silage
It takes confidence to take paddocks out of the grazing rotation for silage. Farmers often fear they will run short of grass.
But by walking swards every week in May, it is easier to see which paddocks can be skipped and cut for silage.
The key thing to remember is that once a paddock has been skipped or closed up, you should cut these swards for silage at the first opportunity.
Don’t hold off mowing grass just to let swards bulk out more, or to justify getting the contractor in with the baler.
Mowing early leaves a green aftermath that is quick to regrow and come back in to the rotation again. Delaying cutting will only slow regrowth, increasing the risk of running out of grass.
Apply fertiliser on a little and often approach
As grass starts to get ahead of cattle, there is a temptation to stop applying fertiliser in May.
However, the lack of nitrogen is more likely to cause grass to head out much earlier than swards which receive fertiliser this month.
Applying 15 to 20 units/acre of nitrogen, on a little and often approach, will help delay swards from heading out.
It will also maximise grass yields during the period of peak growth. Where surplus grass is cut for silage, it will boost fodder reserves for winter.
On paddocks carrying lactating cows, stick to using a nitrogen-only fertiliser such as CAN or protected urea. Avoid high-potash fertilisers as they increase the risk of grass tetany.
Applying smaller quantities of nitrogen fits in with a shorter grazing rotation, helping to avoid issues such as nitrate poisoning in grazing animals.
Splitting paddocks into smaller areas
Use electric fencing to temporarily split paddocks into smaller grazing allocations that last 24 to 48 hours.
Smaller paddocks offer greater control over sward quality, making it easier to skip paddocks and improve cleanout.
Smaller paddocks does mean moving animals more often. But animals quickly become accustomed to frequent handling and will happily move to fresh grass.
Electric fencing can be used to control grazing areas and improve sward quality.
Water provision does becomes a problem when splitting paddocks, but there will be ways of working around this issue.
If strip grazing cattle, make sure to give a big enough allocation and move the fence around the same time every day.
There are plenty of farmers who prefer set-stocking grazing ground for a variety of reasons.
However, even with set-stocking, there are still ways to control grass quality so that cattle have access to swards with plenty of digestible leaf.
One option is to top the field in stages every week. For example, start off by topping one-third of the field on week one.
Top the middle third on week two, then top the last third during the following week.
The idea is that grass will grow in a more controlled manner with fresh regrowth coming every week.
Cattle will be more inclined to graze on the areas with shorter covers after topping, rather than the areas where grass has headed out and is mainly stem.
Read more
Small farmers the big losers from nitrates changes
Updated Kepak-Tirlán beef club to deliver ‘€100 to €200’ over market price
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