High Grass Growth on County Down Dairy Farm

June 4, 2020

Conail Keown – CAFRE Dairying Development Adviser

One of the key targets for Richard Brown is to increase grass growth capacity on his farm just outside Millisle in Co. Down. This article will highlight the progress Richard has made and the impact the various steps have had on his farm business.

Every farm situation is unique in terms of varying soil type, local climatic conditions, stocking rates and the management capabilities of the particular farmer.  The impact these factors have on both grass growth and the quantity of grass utilised is significant. On average only 7 tonnes of grazed grass is utilised per hectare on Northern Irish farms but data from the best commercial and research dairy farms indicate that this can be increased significantly.

With grass clearly the cheapest feed available, increasing growth and utilisation will result in improved farm margin. Research and analysis from AFBI at Hillsborough and Teagasc at Moorepark has illustrated that by increasing grass utilisation by 1 tonne per hectare, net profit can be increased by £190/ha.

Starting point: ‘Measure to Manage’

Richard has identified the weekly measurement of grass cover as a key driver for increasing grass growth capacity on his farm, alongside this he uses online grassland software to analyse grass production data which provides the basis for grazing management decisions.
Richard manages 190 cows on the farm with access to 33 ha grazing block of dry free draining soil. Grass growth on the grazing block averaged just over 10 tonnes dry matter last year. Calving on the farm starts in September with 75% of the herd calved within four months and the remaining 25% of the herd calves between January and March. Farm profitability is a key driver for Richard, while the herd is high yielding, grazed grass and top quality forage form the basis of the herd diet. Milk from forage in 2019 was 2500 litres/cow which has increased to the current rolling average level of 2800 litres from forage.
Richard explains: “I can see getting more from forage especially grazed grass is the way to go for the farm. I also recognise that the grassland on the farm needs to improve, I now place more importance on the grass we grow, its quality and how we utilise it”.

Change in attitude

A change in attitude to grass management has been instrumental on the farm but Richard also maintains the production system needs to change in particular the calving profile of the herd. Currently Richard has 150 cows grazing night and day, the remaining 40 cows are February and March calved cows. In normal circumstances these cows would be out grazing but the current drought conditions (May/June 2020) have limited grass supply. Regardless of this current position these late calved cows are a problem on the farm, the workload and feed costs associated with these cows is relatively much higher. The ultimate aim for this herd is to move towards an autumn block calving profile with all cows calved from September – December. This would simplify the system and allow the herd to capitalise on spring grass growth, especially when good infrastructure is already in place on the farm.

Turnout this year (2020) was on the 5^th March with the earliest calved cows first out by day. Richard wants to change this by not only getting cows out earlier but also increase the proportion of the herd available to go out grazing in early spring. Plans are already in motion to adjust the calving profile and this will take time to implement without incurring significant cost.

Focus on improving soil fertility status

Two key areas to increase the production efficiency of soils are through lime and nitrogen (N) fertiliser use. Soil analysis results on the Brown farm show that the pH is below optimum and the farm would see an immediate benefit from spreading lime. Lime has been spread in 2019 and more planned for this year. Liming offers several benefits including:

• Increase in annual grass production
• Release up to 80kg N/ha/year
• Unlock soil phosphorus (P) and potassium (K)
• Increase the response to freshly applied N, P & K

Lime is essentially a soil conditioner which controls soil acidity by neutralising the acids generated from N fertiliser and slurry applications. Soil pH has a large influence on soil nutrient availability and we should be aiming to maintain mineral soils in the pH range 6.3 – 7.0 and peat soil in the pH range 5.5 – 5.8 to maximise nutrient supply. Soils below this target pH will have a poorer response to applied nutrients of N, P and K.

High annual rainfall leads to a large removal of lime each year with typical maintenance lime requirements suggested by AFBI and Teagasc of 2.5 to 5.0 t/ha once every 5 years depending on regional location and rainfall. Numerous research projects have highlighted correcting soil pH from 5.2 to 6.3 increased grass production by at least 1.0 t/ha. Lime increases the availability of both stored soil phosphate and freshly applied fertiliser phosphorus.

There are two ways to look at P and K requirements. Firstly, all soils below an index of 3 need maintenance levels just to keep them at that index in addition to the growth requirements of the crop. Soils at index 3 do not require any P or K application as there are sufficient soil reserves of to cover maintenance requirements. However, these soils should be sampled regularly to make sure that levels do not drop below index 2.

Secondly, In order to build up soil P and K reserves additional nutrient is required and must be based on grass growth requirement, soil type and soil analysis. Richard has used soil analysis to build his farm nutrient management plan which includes recommendations for chemical fertiliser while also taking into consideration slurry applied on farm.

Maximise the use of slurry

Slurry is a valuable source of P and K on all farms and can contribute to nutrient maintenance. On the Brown farm soil K is the most deficient nutrient across the farm. Richard is using a combination of compound fertiliser and slurry to target these areas. For grazed grass 37.5kg/ha (30 units/acre) per year is required to maintain index 2 in NI, and for build up from index 0 to index 2+ 100kg/ha (80 units/acre) is required. The most amount of K that should be spread in any one application is 112kg/ha (90 units/acre).  Typically, cattle slurry contains 1kg of available N, 0.6kg of P and 2.3kg of K per m3. The nitrogen available in slurry decreases after March unless it is spread with a trailing shoe type applicator.

Research has also highlighted soils with P & K index 2+ will grow approximately 1.5 tDM/ha per year more grass than soils with index 1. Upgrading soils with poor fertility status is essential for the future of milk production in order to allow farmers to fully capitalise on the cheapest feed available to them.

How production efficiency is improving on the Brown farm

• Richard changed the overarching farm strategy from ‘production at any cost’ to ‘production at least cost’.
• Replace or offset purchased feed with grazed grass or forage and push milk from forage above 3000 litres.
• Manipulate the calving profile to capitalise on grazed grass.
• Use soil analysis and nutrient management planning to increase grass growth capacity on the farm.
• Continuous development of personnel skill set and attitude required to manage grass.
• Regular reseeding and a 3-4 cut silage making policy.
• Targeting concentrate feed through the parlour.

Discuss making the most from grass with your local CAFRE Dairy Development Adviser or call 0300 200 7843 and ask to be directed to a CAFRE adviser in your area.