Management notes for May 2021

Date published: 07 May 2021

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).


Prepared by Richard Gibson

Introducing a multi-cut silage system

As we approach the silage season, paying attention to cut and wilt times will help boost quality and reduce dependence on concentrates through the winter. Adopting a multi-cut silage system could help maximise quality and performance from the same acreage. Although cutting earlier will reduce yield per cut, quality in terms of protein, digestibility and metabolisable energy (ME) will increase. Cutting early and wilting rapidly to achieve a dry matter (DM) of 28-32% will significantly help milk from forage. For example, grass cut in early May instead of mid May will be cut at a higher quality with a high D-value.

Rapid wilting is essential, as sugar levels start to decline as soon as the grass is cut. Wilting increases DM and reduces clamp losses from effluent. After cutting, there is a two hour window when the stomata of the plant remain open and water loss is at its greatest; about 100 litres per tonne of grass every hour. After that, water is lost where the leaves are broken or the crop has been conditioned. As first cut is taken earlier in a multi-cut system, when weather conditions may not be ideal, tedding allows for air movement over the crop, helping evaporation.

Ideally, in a multi-cut system the time between cuts is reduced to four or five weeks. Individual cuts will be lighter compared to the traditional system. Therefore, it is worthwhile discussing the effect of the lighter cut on price with your contractor. A 1.0 MJ per kg DM increase in ME is generally achievable when moving from a traditional to multi-cut strategy. DM intakes can increase by over 1.0 kg DM per cow per day when feeding this forage. This enables an increased target for milk produced from forage. Increased milk production from home grown sources will reduce concentrate requirement and therefore more than pay for the extra contracting costs of cutting more frequently.

With reduced cutting intervals, pay special attention to crop nutrition to ensure all the nitrogen is absorbed before harvesting. Apply slurry immediately after harvesting. Fertiliser should also be applied as soon as possible and not more than 2.5 kg nitrogen (N) per hectare (two units per acre) for each growing day between cuts. As crops are lighter consider how long the crop is wilted. To achieve 28-32% in ideal weather conditions, 24 hours wilting should be sufficient. As the grass is leafier, fibre levels are low. Increasing the chop length to 5 cm will therefore help with ensiling and fermentation. To maintain rumen health, the diet may need to be supplemented with extra fibre such as straw or haylage.

Clamp management

Clamp management is key to minimising loss of nutrients. If dry matters are desirable, the silo needs to be filled quickly and grass distributed evenly. The aim is to remove the air and make the clamp as airtight as possible. Spread the grass in shallow layers and roll continuously. Ideally, the silo should be covered immediately and the cover weighted effectively, paying particular attention to the shoulders of the pit.

Slurry and fertiliser application

The phosphate (P) and potash (K) recommendations for second cut silage vary according to soil reserves. If you have a recent soil analysis for your silage fields, use the online CAFRE Crop Nutrient Recommendation Calculator to work out slurry and fertiliser requirements for second cut silage.

As a guide, at soil index 2 for P and index 1 for K, typical of fields normally cut for silage, slurry has the potential to provide some of the N and K and all the P needed. Practically, a 22,000 litre application of dairy cow slurry per hectare (2,000 gallons per acre), ideally using a low emission spreading technique, contains 17 kg of N, 26 kg of P and 63 kg of K. Top up with 375 kg per hectare of a 22:0:10 type fertiliser (three hundred weight bags per acre) to meet second cut needs. The majority of second cut silage swards will give a positive response to applying fertiliser containing sulphur.


Prepared by Nigel Gould

Breeding in the spring calving herd

Breeding for most spring calving herds will start in the coming weeks. To achieve the desired target calving index of 365 days, ideally cows should have a body condition score (BCS) of at least 2.5 and be on a good plane of nutrition. Ensure adequate grass supply and quality during this period. Consider mineral supplementation at grass, particularly selenium, iodine and copper. Where a stock bull is being used, regularly monitor heat activity to identify a higher than normal repeat rate. Sub fertility is often reported with bulls that previously proved fertile.

When AI is used, heat detection is the main barrier to success. Ideally, observe cows and heifers three times per day. If this is not practical, consider methods to improve heat detection. A vasectomised bull, fitted with a harness and chin ball containing a type of paint, can offer good success rates for some herds. A growing range of high-tech products are available which incorporate IT and electronic identification (EID) and can be used along with a vasectomised bull. These will provide more accurate information on the timing of increased activity.

Tail paint and scratch card or ink well type products offer varying levels of success, depending on the farm. False alerts have been reported where cows or heifers scratch themselves under trees or bushes, particularly in warm weather.

Nematodiris risk in lambs

May is generally the month associated with a high nematodiris risk in lambs which can lead to high mortality among those affected. Lambs that survive can have reduced future growth potential due to permanent gut damage. Symptoms include a sudden onset of profuse diarrhoea and dull lambs which stop sucking and quickly become dehydrated, with obvious condition loss. Symptoms are like those of coccidiosis however, green scours are associated with nematodiris whereas dark grey or blood stained scours (black in colour) are associated with coccidiosis. Ewes are not affected as immunity will have developed.

Nematodiris has a different life cycle to other worms as the development of the infective larvae takes place within the egg and infection passes from one lamb crop to the next in the following year. The infective larvae are resistant to low winter temperatures and hatch when environmental temperatures reach approximately 10oC for a period of several days. Peak hatching periods vary from year to year depending on temperature. The risk is greater for lambs as their dependence on grazed grass increases. For this reason, lambs more than six weeks old or younger lambs from ewes with poorer milk yields are most at risk. The risk will be lowered by grazing areas not grazed by lambs the previous spring. As infection is caused by developing larvae and adults before they lay eggs, faecal egg counts are not beneficial. Post mortem examination may show large numbers of developing larvae and adults in the small intestine. White drenches (Group 1-Benzimidazole) are the recommended treatment for nematodiris as there are no known resistance issues. This treatment will also help in the fight against anthelmintic resistance in other worm species and anthelmintic classes in the future. Discuss appropriate parasite control with your vet.

Silage harvesting

Those aiming to produce high quality silage will be targeting a harvest date in May. Aim to harvest before too much seed emergence occurs as this will avoid reduced D-values associated with later cutting. There is sometimes a worry that nitrate will still be present in the grass. A rule of thumb is that 2.5 kg of nitrogen per hectare (two units per acre) will be used up in the crop daily. This figure is lower in periods of low grass growth and higher in periods when growth is good. Nitrate is less of an issue if a good wilt has been achieved.


Prepared by Liz Donnelly

Extra water at weaning

Weaning is a very stressful time for pigs due to the many changes that take place. As well as separation from the sow, pigs are moved to a different house, mixed with other pigs, often in a large group, fed a solid diet and provided with a different water source. Due to these changes a period of low and variable feed intake is common, often lasting seven to ten days. Getting pigs to eat as soon as possible after weaning is therefore very important. Not only does it improve post weaning performance, it also has a positive effect on lifetime performance.

Providing extra water at weaning encourages pigs to eat more. Before weaning the daily fluid intake of pigs is about 700 mls. However, water intake on the day after weaning is often less than 300 mls that is almost 60% less. In the first week after weaning water intake does increase, but only to about 440 mls per day. It is not until the second week after weaning that pigs drink more than they did before weaning. This obviously affects feed intake as pigs that don’t drink, don’t eat!

To encourage weaned pigs to drink it is important they have easy access to fresh water. Consider the following:

  • Provide an extra source of water for three to four days after weaning, for example turkey drinker. Water from a turkey drinker is easily accessible.
  • Use bowls rather than nipple drinkers as it is much easier for pigs to find water in a bowl. A bonus of using bowls is that water wastage is 30% less.
  • Use the same type of drinker in the weaner house as was used in the farrowing house, as the pigs will be familiar with this type of drinker.
  • Regularly check the flow rate from drinkers. Restricted flow can reduce feed intake by as much as 15%. The recommended flow rate for newly weaned pigs is 0.3 litres per minute, increasing to at least 0.5 litres per minute for pigs up to 20 kg. Check all drinkers when measuring flow rate as it is often lower the further drinkers are from the supply.

Free farrowing pens – issues to consider

Before making any changes to genetics, nutrition, management or housing it is always a good idea to discuss your thoughts and plans with others. This is most definitely the case if you are thinking of installing free farrowing pens. With this new system of housing there are a lot of design and layout issues to consider. As well as sow welfare, think about your safety and that of your employees when working with the sows and pigs. Protection of the piglets from over lying and injury is also a key consideration when planning such a system.

The following are a few areas to think about:

  • Pen size – the pen should be large enough to allow free movement of the sow and meet any future legislative requirements.
  • Floor/slat type – the floor must be strong enough to support the weight of the sow as she moves about and suit both sows and piglets. It must be well supported and non-slip. As pen hygiene is crucial the floor must allow for good drainage and removal of faeces.
  • Pen division height – divisions should be high enough so the sow feels protected, but not too high that you cannot see the sow and pigs. Also, should the walls be solid, open bars or a combination of both? Although solid plastic walls are more hygienic and easier to clean, part barred divisions may encourage sows to dung in a particular area.
  • Creep/heat pad – the creep/heat pad should be large enough to accommodate all the pigs and be protected from the sow. Good design allows you to close the pigs in this area without going into the pen.

Not getting the size, layout and design of free farrowing pens correct could result in higher piglet mortality, poorer sow welfare and health and safety concerns.


Prepared by Leigh McLean 


Similar to last year, the swing from very wet to dry and cold has put struggling crops under pressure. This has widened the gap between good and marginal, sometimes within the same field. Keep a close eye on crop development making sure key timings of fertiliser and sprays are not missed. Little visible disease and dry weather will tempt some growers to delay fungicide application or stretch spray windows. It is important to maintain good timing as most fungicides act preventatively. The effect of a missed timing will only be visible weeks later, by which time the fungicides curative activity is less effective at controlling disease and maintaining the crops yield potential.

Winter barley disease control

Slow early development meant T1 sprays were only applied towards the end of April. Aim to apply the T2 fungicide three to four weeks after T1, ideally when the flag leaf and the first few awns have emerged. Best performance comes with Prothioconazole plus an SDHI in the mix, where crops have the yield potential to justify the additional expense.

Winter wheat disease control

To maintain longevity and efficacy of cereal fungicides it is important to use them responsibly as part of fungicide programmes. This minimises the risk of resistant septoria strains developing. Follow label advice on applications per season: only use where necessary, keep up dose rates of actives in mixes and always use in combination with a multisite protectant such as Folpet, which protects other active ingredients in the mix. 


Spring cereals were sown mostly in good time into good seedbeds. Some received a pre or early post emergence residual herbicide. However, dry weather at application means this weed control strategy may not be as effective as desired and a top up may be needed. If herbicide has not yet been applied, apply a mixture of at least two broad spectrum herbicides when most of the weeds are at the two-four leaf stages ensuring weed competition is removed early.

Early sowing should mean good yield potential for spring cereals. Tank mixing a low rate fungicide with the herbicide will prevent disease becoming established and protect yield potential.

Apply nitrogen top dressing once tramlines are visible at the two-three leaf stage (GS 12 to 13). Later applications than this may green the crop but add little yield. Inspect protein crops for grass weeds and volunteers. If necessary, apply a graminicide (grass weed herbicide) once grasses have emerged and before the crop canopy closes over. A fungicide is recommended for beans at mid flowering to control chocolate spot and bean rust, usually applied in the second half of June.  


Plans should be in place for early weed control. When using pre-emergence herbicides check regularly to ensure they are applied on time to avoid crop damage.

Although Diquat was reintroduced late last year for desiccation, this was only a temporary measure and is highly unlikely to be repeated this year. The alternatives, PPO inhibitors Spotlight and Gozai, are effective on crops that are starting to senesce, but they typically take one to two weeks longer to give the same effect as Diquat. For later plantings take the shorter growing season into consideration and reduce nitrogen (N) by 1.0 kg per hectare per day past the target planting date. Apply the remaining N pre crop emergence. Careful N management now will encourage earlier natural senescence and improve the probability of a successful burndown without Diquat.

You are reminded blight samples submitted from Northern Ireland were predominantly of the A37_2 strain which has reduced sensitivity to Fluazinam (Shirlan). Given the widespread occurrence of this strain in Northern Ireland Shirlan for blight control can no longer be relied upon.   

Notes to editors: 

  1. Follow DAERA on Twitter and Facebook.
  2. All media queries should be directed to the DAERA Press Office.

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