Management notes for July 2019

Date published: 05 July 2019

Management Notes are prepared by staff from the College of Agriculture, Food and Rural Enterprise (CAFRE). CAFRE is a college within the Department of Agriculture, Environment and Rural Affairs (DAERA).

Have you enough silage to meet requirements?


Prepared by: Christopher Breen

Fertiliser application in July

Take the opportunity to produce extra grass this grazing season by applying between 35 and 50 kg nitrogen (N) per hectare after each grazing. Research at AFBI has shown Calcium Ammonium Nitrate (CAN) is the most effective source of fertiliser N during the summer months.

Calculate forage requirements for winter now!

Have you enough first and second cut silage to meet requirements? If not, there is still time to plan a third cut. Use Tables 1 and 2 to estimate supply and demand on your farm. Firstly calculate the volume of silage in your pits by multiplying the length by the width by the height. To convert volume of silage to tonnes select the correct conversion factor from Table 1 and multiply this figure by the volume figure. The conversion factor selected depends on the dry matter of the silage.

Table 1: Conversion factors to convert silage volume to tonnes of silage
Silage DM % Tonnes of silage per cubic metre
20 Multiply by 0.77
25 Multiply by 0.68
30 Multiply by 0.60

Table 2 estimates the monthly silage requirements for housed livestock. To calculate the silage requirement for your farm this winter multiply the figures by the number of stock in each class. Then multiply this figure by the number of months you normally feed silage.

Table 2: Estimated monthly feed requirement of stock eating 25% dry matter silage
Livestock Silage (tonnes per month)
Dairy cow in milk 1.4
Dry cow 0.9
0-1 year heifer 0.6
1-2 year heifer 0.9

If you haven’t enough silage estimate how much land to close off for a third cut, taking into account that a third cut produces 10 tonnes of silage per hectare after seven weeks growth.

The CAFRE Crop Nutrient Recommendation for third cut silage at soil index phosphate 2 and potash 1 shows that 250 kg per hectare (two bags per acre) of a 22:0:10 type fertiliser and 16 cubic metres per hectare of dairy cow slurry (1,400 gallons per acre) can meet third cut needs. A sulphur containing fertiliser should also be used, applied at a rate of up to 35 kg per hectare.

Pre-reseed drainage repair

Fields for reseeding may benefit from improvements to drainage or soil aeration. Clean out sheughs that are blocked with silt/grass. Also examine outflows from existing shores to ensure they are still running. If new drains are needed plan and design the most appropriate solution for the site.

Soil compaction

Compacted soil has been squashed into a solid layer, restricting root growth and reducing grass response to N. Dig test holes at least 40 cm (16”) deep to determine the extent of the problem and the depth of any compacted layer. Visible signs of compaction include a structure that is hard to break up, shallow roots growing horizontally, few worms present, a bad smell and grey colour/brown mottling. The depth of the compacted layer determines the type of machine that should be used to correct the problem.

July jobs checklist

  • To maintain sward quality top grazing swards containing old dead grass or seed heads.
  • Calibrate parlour and out of parlour feeders to ensure accurate feeding.
  • Where necessary, burn off swards towards the end of July to allow for reseeding during August. 
  • Assess heifer performance to determine if they are meeting targets.
  • Assess whole-crop swards and harvest when the grain is like a ‘soft cheddar’ (approximately 40% dry matter).


Prepared by: Nigel Gould


If planning to reseed this year aim to have it completed by mid-August. This ensures the reseed has the best chance to succeed and may allow at least one grazing pre-winter. Grazing promotes plant tillering, giving quicker ground cover. It also allows for a post-emergence spray to be used for weed control five to six weeks post-sowing. Targeting weeds at this early stage, before significant root development occurs, increases the rate of success.

It is important soil pH, phosphorus (P) and potassium (K) are at optimum levels to achieve a good reseed. Aim for a pH of 6.3, a P index of 2+ and a K index of 2-. For soils with P and K indices of 2+ and 2- the recommended P and K application rates are 50 and 60 kg per hectare respectively. Adopting an appropriate fertiliser and liming strategy is vital to sustain the new sward and minimise the re-occurrence of weeds and less productive grass species.

Decide on a cultivation technique that best suits the particular type of land. Conventional ploughing is often the best however, where soil is shallow and stoney, a min-till approach is more appropriate. The more common form of min-till involves discing (two to three passes in alternate directions) and/or harrowing, followed by sowing the seed. It is important to graze or mow/top tightly to minimise the amount of thrash in the sward. Direct drilling into an existing sward is also an option. This usually involves the seed being dropped into a shallow channel created by a disc. The aim when direct drilling is to minimise competition from the existing sward. For this reason, direct drilling straight after silage harvest or after the sward is tightly grazed maximises success rate. Ploughing, where possible, will act as a remedy for compaction and should also help with drainage.


Lungworm cases generally peak in July/August. Monitor young stock in particular and watch out for coughing and panting after light exercise/running. In more extreme cases neck extension and mouth breathing are seen and damage is often irreversible. Although more common in young stock, cases in cows have become more common in recent years where natural immunity has not had a chance to develop properly.

Remove the bull

Spring calving herds will be coming to the end of the breeding season on most farms. A cow served on the 18 July and assuming an average gestation period of 286 days, will calve on the last day of April next year. Therefore if you don’t want any calves born in May next year remove the bull in mid-July.


Foot rot and scald (inter-digital dermatitis) are the main causes of lameness in sheep, both of which are caused by the bacterium Dichelobacter nodosus. Scald is often treated using oxytetracycline aerosols in individual sheep or foot-bathing where several sheep are affected. For best results when foot-bathing allow sheep to stand in solutions for a short time rather than just running them through. Stand the sheep in a dry yard to allow the solution to dry. If using formalin, solutions above 5% can cause severe irritation, therefore avoid the practice of ‘topping up’ footbaths. Mix accurately and avoid solutions over 3%.

Foot rot, unlike scald, extends to under-run the hoof wall or sole and is accompanied by a characteristic foul smell. Foot-bathing may limit the spread of foot rot in the early stages but is not an effective treatment. As contagious ovine digital dermatitis, another cause of lameness, can sometimes be hard to distinguish from foot rot it is important to consult your vet to get a correct diagnosis. Appropriate quarantine protocols for purchased sheep, along with a strict culling policy for persistently lame sheep, will also help control the problem.


Prepared by: Jason McFerran

Measure monthly to manage

How is your farm performing? Regardless of the type of farm you run you can answer that question by looking at a long list of key performance indicators including herd health, fertility, growth rates, feed efficiency, milk from forage, lambs per ewe, pigs per sow, milk yield, milk solids and many more. The old adage ‘you can’t manage what you don’t measure’ is very true. Without monitoring herd performance, it is very difficult to manage the farm business.

CAFRE has been offering an annual benchmarking system since 1999. This allows you to assess farm business performance on a yearly basis and compare your business with other businesses. Annual benchmarking is an important tool for any business as it takes into account all the costs and receipts for each farm enterprise. However, by definition it is always looking back over a 12 month period.

Businesses performance should be monitored on an on-going basis, using the most up to date data, if at all possible. This allows for timely management decisions to be made throughout the year.

With this in mind, CAFRE has developed an additional online tool that lets dairy farmers assess their herd performance on a monthly basis. Margin Over Concentrate (MOC) is a simple, useful measurement tool, looking at the income from milk sales and the cost of concentrate feed for the dairy herd during a month.

Concentrate feed accounts, on average, for about a third of the overall cost of production for a Northern Ireland dairy herd. This of course depends on the system of production, with some systems spending a significantly higher proportion. If concentrate usage can be managed efficiently this impacts on the profit generated.

Input figures required to calculate MOC

Three sets of figures are required:

Cow numbers:

  • Cows in milk at end of month
  • Dry cows at end of month

Milk details:

  • Litres sold
  • Litres used on farm (or dumped)
  • Value of milk sold, less transport

Concentrate details:

  • Tonnes of blend used
  • Cost per tonne of blend
  • Tonnes of nuts used
  • Cost per tonne of nuts

It should take only a few minutes to enter these figures. The MOC tool is accessed through the DAERA Online Services page and is available to all dairy farmers. Each of the figures relates to the month that has just passed. As soon as the milk cheque is available the figures can be entered.


The results that are calculated from the input data provide up to date indicators of herd performance. You can use all of this up to date information to set production targets for the current month.

Monthly results:

  • Daily yield per cow
  • Daily concentrate fed per cow
  • Daily milk from forage
  • Concentrate fed per litre
  • Concentrate cost per litre
  • Daily MOC per cow

Each farmer who enters data will see a league of anonymous results allowing them to compare their herd performance against the top, bottom and average results. Once 12 months of data have been entered the system will display rolling annual averages.

The next time you log on to DAERA Online Services to register a calf on APHIS Online, look out for the blue ‘CAFRE Benchmarking’ button and put a note in your calendar for the day the milk cheque arrives to fill in your MOC data.


Prepared by: Jayne Mooney

DAERA launches Code of Good Agricultural Practice for Reducing Ammonia Emissions

This Code of Good Agricultural Practice for Reducing Ammonia Emissions (the Code) has been produced by DAERA, in collaboration with the farming industry to provide guidance on how to reduce ammonia emissions.

The Code explains the practical steps that farmers in Northern Ireland (NI) can take to minimise ammonia emissions. From the storage and application of organic manures, the application of manufactured fertiliser and through modifications to livestock diets and housing by applying well researched techniques.

Ammonia is an important air pollutant that can have significant effects on both human health and the environment. The government has agreed to reduce ammonia emissions by 8% in 2020 and by 16% in 2030 compared to 2005 levels. Around 94% of ammonia emissions in NI are from agriculture and the achievement of these targets will require widespread adoption of the measures in the Code. The Code is available on the DAERA website.

Bracken control in July

Timing of control methods for bracken are critical as the plant has over ten times its mass below the ground as above. As fronds develop in the spring, the energy reserves in the rhizomes diminish and only start to become replenished once the fronds are fully extended. Control options, depending on site safety, include spraying, weed wiping, cutting and rolling but success requires repeated action. Control is important for four reasons – land eligibility, habitat damage, water quality and disease. Bracken can form a very thick stand of vegetation resulting in shading from the bracken canopy. This may be so severe that little or nothing can grow beneath it, sometimes at the expense of a priority habitat area such as heather moorland or semi-natural grassland.

Bracken contains Ptaquiloside, a natural phytotoxin, which has been identified as a carcinogen affecting stock and water quality.  Bracken provides a refuge for ticks which are linked to redwater and louping-ill in stock and a developing issue in people of Lyme disease. Bracken is not eligible for area based Schemes. Further information is available in the ‘DAERA 2019 Guide to Land Eligibility’ available from the DAERA website.

The most effective control is spraying with the selective herbicide Asulam in July after full frond expansion. Asulam was previously withdrawn but has been made available under emergency licence for the past seven years for use between 1 July and 31 October. Only buy the required amount as storage beyond October is not permitted under pesticides legislation and therefore cross-compliance.

Further information about the Emergency Authorisation (including key dates for 2019) is available from the Bracken Control website.

Application of the non-selective herbicide Glyphosate to bracken with a weed wiper can reduce the risk to other vegetation and is successful if a wetting agent is used. Cutting or rolling can also be used and works on the principle of repeated treatments to weaken the bracken and exhaust the reserves in the underground storage stems.

Cutting or rolling should be carried out from mid-June as the plants reach maturity with a second treatment in August. A minimum of two treatments per year for four years will be required. All these treatments should not start until after mid-July if ground nesting birds are present.

CAFRE’s control plots have achieved a consistent 95% bracken reduction with one spray of Asulam, costing approximately £150 per hectare in chemical cost. There was little regrowth and no damage to the underlying habitat. From one year’s data it appears that the cheaper chemical option of Glyphosate weed wiping has reduced bracken cover by up to 80%, but further control will be required. Cutting plots have shown stimulated frond production initially so must be repeated with dedication over several years. Rolling twice each year has shown some success, with variable results (30-90%) between sites.

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