Nutrition first

Paying good attention and allowing the correct time and preparation of all stages of silage-making should help improve silage quality and positively impact feed costs and animal performance.
Grass silage remains the most common forage in cow diets across Ireland. However, it is the one element of the diet that has huge variation from farm to farm. Whether your farming system is high or low input, quality grass silage is non-negotiable. The objective on every farm should be to produce high-quality silage and improve efficiency by reducing field and clamp losses where possible. Preparations before silage is cut are crucial; pits should be clean and all necessary plastic and covers ready. Adequate fermentation time is needed between ensiling and opening the pit for good palatability, so feeding out must be managed to allow enough time to elapse before the pit will be re-opened. Finally, it is important to implement feed budgets to analyse how much silage needs to be made; poor weather conditions over the last number of months have shown how crucial it is to have good reserves.

Forage 

Cows are designed to eat forage, so making and feeding high-quality digestible silage is a must. Maximising forage intakes is key to improving farm profitability. Poorer-quality silage requires additional supplementation to achieve the same performance, bringing in additional feed costs.
For example, if a cow eats 10kg (approximately 43kg fresh weight) of dry matter (DM) of a 75-DMD silage with a UFL (forage unit for lactation) content of 0.85, the energy intake of the cow is 8.5 UFL. Whereas if the cow eats the same amount of a poorer silage (65 DMD), with a 0.72 UFL, she will only get 7.2 UFL of energy. While this difference of 1.3 UFL seems small, it is enough energy to produce three litres of milk. For this cow to achieve the same performance as the first, an extra 1.5 kg of concentrate will be required, resulting in additional costs. Good-quality grass silage should have a UFL >0.8 or a metabolisable energy (ME) of 11.5-12 MJ/kg DM, a crude protein of at least 14 per cent and a DM content of 27-30 per cent.
While fertiliser and slurry have been difficult to manage this year, they should have been applied at levels tailored to your own farm’s needs. Representative soil testing should be done regularly to ensure good optimum soil fertility levels. Optimum soil pH is also vital and should be between 6-6.5. Without this basic feature, you will struggle to manage the other parameters.

Harvest

At harvest, we need to be careful if there is still nitrogen in the grass. Excess nitrogen impacts grass ensilability, which may result in poorer fermentation. Too much nitrogen can produce grass with low sugar levels, meaning the silage could have high ammonia and butyric acid, causing palatability issues. On the other side of that, too little nitrogen can cause low protein silages and reduced yields, as we saw last year. We sampled over 1,100 silages in 2023, and our results averaged 29 per cent DM, 12.9 per cent crude protein, 10.4 metabolisable energy (ME) and a DMD of 68.8.

The biggest factor that contributes to nutritional value is cutting date. For the best silage, an early cutting date, before the plant has headed and a seed head is visible, is vital. Each day that passes beyond this point, the DMD value will decline by 0.5 units. So, aim to cut just before the seed head emerges. Do not sacrifice quality for quantity, as it is possible to achieve both. Aim for an early-May cutting date, as later will impact on second and third cuts and cause forage quality issues for the remainder of the year.

While it’s not always possible, cutting on a dry, sunny day is ideal. Grass sugars are at their peak in the afternoon, but you also need to consider a fast wilt. An overnight wilt might not be adequate. Also, consider that wet ensiled grass will be too acidic, producing an unpalatable feed. Effluent is also likely to be at a DM of less than 25 per cent. A target dry matter of 27-30 per cent is ideal. Grass can also be too dry, resulting in consolidation issues, poor ensiling or secondary fermentation in the pit and aerobic spoilage or heating once opened. 
The mower should not be dropped below 6-7cm to help avoid soil contamination and encourage good regrowth. Once cut, the grass needs to be ensiled as quickly and cleanly as possible to prevent losses (<24 hours). A longer wilt time leads to bigger losses. Chop length should be 2.5-5cm for 25 per cent DM crops.

Weather

Irish weather can be unpredictable, and we need to bear that in mind here. If weather conditions are difficult, mowing should be held off until the weather settles. However, do not delay too long, as soil contamination will become an issue. If possible, use different access points in fields and make sure the area in front of the clamp remains free from soil. Work downhill and make sure tyre pressures are correct for the conditions. Part-filling trailers should also be considered. Be prepared and remember that wet grass will also produce a lot of effluent.

Additive

Silage additive can help make good silage great, but it will not compensate for poor silage management. No one additive is ideal in all farm circumstances. A homofermentative additive (such as Alltech’s Egalis) which supplies one million bacteria, can help improve silage quality. The aim of this additive is to speed up the fermentation process using lactic acid bacteria, reducing the pH to the required level and preserving more of the nutrients in the crop. The result is less waste and increased performance, which fits in well with the focus on improved efficiency and sustainability. You will have to make an informed decision based on the conditions and allow adequate time to get the product and the correct equipment for application.
Put aside time to prepare the clamp before harvesting begins. This can help speed up the operation. Old, mouldy, rotten silage should already be removed from the clamp. To ensure quality, the clamp needs to be filled as quickly as possible, paying good attention to detail. Good compaction from the very start is vital for clamp stability and to reduce losses. Even filling and regular rolling is a must; however, avoid rolling the next morning before filling if a pit has been left overnight, as this will draw in air. Clamps should be filled in a wedge shape. Do not overfill the clamp as consolidation above the walls will drop significantly, creating losses. Finally, the pit needs to be sealed as soon as all compaction is complete.
Paying good attention and allowing the correct time for adequate preparation of all stages of silage-making should help improve silage quality and positively impact feed costs and animal performance.