Maintaining mid-season protein and solids through grass quality

Agriland

28-05-2025

Grass quality and nutrition of the cow during the mid-season can be the main concern for farmers, as trying to hold peak milk production for as long as possible is crucial for the total solids produced/cow at the end of the season.
It is fair to say that we have had an exceptional spring, which has allowed grass to be in the herd's diet from early on this year.
Growth rates struggled early on but eventually surged around the middle of April. They have slightly slowed down again due to a lack of rain.
In this changing weather, you can go from surplus of grass to a deficit within a matter of days, so keeping grass ahead of the cows while maintaining quality can sometimes be a struggle.
With the recent soil moisture deficits around the country, the grass plant has gone through a phase of stress which has caused it to go to seed (reproductive phase) very quickly in many cases. This has meant that keeping quality in front of cows has been difficult.
However, when the weather and growth rates are fluctuating, farmers should be walking the farm twice weekly so timely decisions can be made for either taking out surplus paddocks for bales or supplementing extra meal or silage in a surplus or deficit situation.
Topping paddocks after grazing might be an option for many farms that are not in a position to take out paddocks but need to correct quality. This needs to be done immediately after grazing so that re-growths are not affected.
Grazing poor quality grass is the biggest risk to milk production in the mid-season, which means farmers need to ensure they are grazing optimal covers throughout the summer months.
Grass quality
According to a Teagasc study, during the first 11 weeks post-calving, varying levels of nutrition affected both milk production of cows during the mid-season and throughout the entire lactation.
The research showed why a cover of 1,400kg DM/ha was optimal for cow performance and health, regardless of the stocking rate.
Cows receiving no concentrates and grazing 1,400kg DM/ha covers produced 23.9kg of milk compared to cows grazing a cover of 2,000kg DM/ha and being supplemented 6kg/head/day producing 23.7kg of milk.
These covers were compared again, this time receiving 2kg/head/day of concentrate on each. The cows grazing 1,400kg DM/ha covers had an intake of 16.2kg of grass and produced 26.2kg of milk.
The cows grazing the cover of 2,000kg DM/ha had a grass intake of 14.5kg and the cows produced 19.7kg of milk.
Grazing covers of 1,400kg of DM/ha with 2kg of concentrates is seen as the best balance of cow performance, cow health and maximising the grass utilised out of the paddock.
Protein
In a recent Lakeland Dairies advice video, Lakeland Dairies/Teagasc joint programme adviser, Michael Monaghan highlighted that protein levels should be rising from the month of March right through until December.
In relation to the border-midland-west region, Monaghan said: 'There's a major issue when it comes to mid-season protein as we are losing 0.2% in the month of June every year.
He highlighted that with the current high growth rates, it is important that farmers are walking the farm every five days.
The adviser said that this drop in protein is a result of farmers grazing covers over 1,500kg of DM/ha and if cows are not allocated enough grass, this will also cause an impact on protein levels.
He also highlighted the importance of keeping the cover/livestock unit (LU) between 180 – 200kg DM/LU.
Above these levels, Monaghan said: 'Farmers should remove any excess grass immediately in order to ensure that pre-grazing covers are still correct and we are maintaining protein levels on the farm.'