Farming: The time for high-performing silage is now

Cutting your silage earlier, a simple change of practice on many drystock and dairy farms, can have a major impact on both animal performance and meal feeding levels next winter.

Beef finishing or weanling systems and winter milk systems are alike in one particular way, both need excellent quality silage to avoid unnecessary meal feeding in order to maximise animal performance.

Over many years of research, Teagasc has examined the relationship between silage quality and animal performance, both under beef and dairy systems. 

A simple conclusion from the data presented in table 1 and 2 shown here, where cutting date is earlier in the season and high dry matter digestibility (DMD) grass silage is produced, animal performance levels can be optimised from lower levels of concentrate input.

Table 1: Beef cattle weight gain based on silage quality

Table 2: Dairy cattle milk yield based on silage quality

Why all the fuss about silage quality?

The benefits of excellent quality silage extend further than just a concentrate input saving. 

From a beef production perspective, higher quality silage results in better liveweight gains from finishing animals, shorter days to finish and, as a result, lower fixed costs through slurry and shed space savings. 

For milking cows, higher DMD silage benefits include improved forage intake, more milk solids production and milk from forage, better rumen health and, of course, lower concentrate feeding levels.

Some farmers often struggle with the concept of earlier silage cutting, often citing a lack of winter feed next winter as the primary concern and instead opt for a bulky first cut approach. 

As always, the completion of a winter feed budget for all farms is a must. 

However, Teagasc research shows that you are better to take two cuts, starting early to get higher total yield and better quality. 

Where a two-cut system, starting with the first cut in mid-to-late May, is operated, an extra 1t/ha of dry matter is produced – the equivalent of 4.5 bales/ha of silage – over and above a system where the first cut is taken on June 12.

The quality of the silage will also be far superior when cut earlier. 

As we move from mid-May through to mid-June, the grass plant enters its reproductive phase and throws up stem and seed heads.

Although you are getting additional bulk in your first cut, you are bringing in a lot of poor-quality material, which offers very little nutritional value to the animal. Silage cut in early June will struggle to be 65DMD, with this worsening if the sward was not grazed before closing. Where silage swards have not been grazed prior to closing, a mid-May cutting date should be prioritised.

The Irish grazing system

Most livestock farmers in Ireland operate a grazing system based on maximising grazed grass in the diet. 

Across dairy and beef systems, the benefit of maximising grazed grass as a proportion of the total diet is very clear. However, seasonal patterns of grass growth means that there is practically no growth in winter, limited growth in early spring and early winter, with peak growth in May and June. 

Grass supply is in surplus during this peak growth and consequently grass silage is made to match supply and demand, maintain grass quality and provide winter feed when grass growth is at its lowest.

Grass silage thus accounts for 20-25% of total annual feed per cow on well-run dairy farms, and up to 30% of total feed on beef farms, depending on the production systems in place. 

Over 85% of farms in Ireland make silage each year, and the estimated cost of harvesting over 1 million ha of grass silage exceeds €500 million annually. 

Clearly this is a significant cost component of our ruminant production systems.

At the field level, the single biggest factor contributing to the cost of producing silage is the yield of the crop. The primary challenge for farmers is to maximise silage yield, while at the same time achieving target silage quality for production system on the farm.

There is a balancing act in silage production, between maximising yield and maintaining feed quality (DMD). 

During the milk quota area, many spring calving dairy farms moved to a low DMD/high bulk first cut silage system, which suited low stocking rates, early dry-off and long winter dry periods. This strategy may need to be adjusted for the post-quota era to account for increased spring/autumn feed demand and shorter dry period durations. 

Based on surveys of silage analysis results over recent seasons, it is clear that silage quality on beef farms also needs to be addressed. 

Mean silage quality on beef farms sits at 66 DMD, which is adequate for dry suckler cows in good body condition but is a low-grade feed for growing and finishing cattle.

Soil P & K concentrations, as well as pH (lime requirement), have been depleted in recent years. This is reflected in sub-optimal grass growth and consequently light yields at target harvest dates. 

The consequence of this is later cutting dates to maximise yields, which results in poorer quality silage. 

It is imperative that soil fertility is optimised and the correct fertiliser regime is applied to allow farmers to achieve target silage quality.

Understanding optimal time of harvest, the role of additives, and the benefits of reseeding silage areas are also important.

As a stand alone feed silage is expensive to produce. But looking at silage as part of an integrated grassland management system, grazed grass plus grass silage are competitive feeds and over 2.5 timed cheaper than concentrate feeds.

Planning your grass silage strategy 

A good management plan will deliver on the three main objectives for quality silage:

• Good yield for first cut silage with high annual grass tonnage per hectare 

• A clean, well-preserved feed with good palatability 

• The appropriate nutritional quality (DMD) 

The objectives of high dry matter yield and good preservation remain consistent across farming systems. Optimum DMD will vary depending on the type of stock being fed, e.g. freshly calved dairy cows versus dry suckler cows.

The main factor affecting DMD is crop maturity at harvesting. Assuming good early season management, ryegrass swards and correct soil fertility, target cutting date should be dictated by the type of silage required.

Most farms carry more than one class of stock over the winter, so more than one type of silage may be required. This should be factored into the silage plan.