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Building forage reserves

Building forage reserves

Joe Patton, Teagasc Dairy Specialist, & Siobhán Kavanagh, Teagasc Regional Manager recommend that farms build a rolling silage reserve of 2 bales/head or about 1 month’s feeding for a mature cow, into their silage plans, to offset against future shortfalls in fodder due to non-seasonal weather.

In 2017–2018, most farms experienced severe winter conditions followed by a summer drought that reduced annual grass growth by one quarter. To cope with such shortages, we recommend that farms build a rolling silage reserve of 400kg DM per livestock unit into their silage plans. That is equivalent to 2 bales per head or about 1 month’s feeding for a mature cow, and should be added to normal local guidelines.  Optimising stocking rate creates a long-term balance between forage utilisation and controlling feed cost. This separate provision is needed to insulate against poor grass growth and field conditions within year.

Building a reserve

This level of reserve represents a practical compromise between feed security and the cost of making and storing additional feed.  Individual farmers can consult their Teagasc adviser to assist in devising the most appropriate means of building reserves for their own circumstances. In practice, developing a reserve will happen through a combination of better silage management within the farm gate and strategic purchase of a reserve, where required.

A key benefit of maintaining an adequate forage reserve is that the product options for supplementing diets are much increased in difficult years. Where the daily deficit is <10% on a DM basis, low fibre (NDF) concentrate products, based on native cereal and protein sources, can be readily used. On the other hand, larger proportional deficits necessitate the inclusion of high fibre by-product feeds to meet nutritional standards. Much of this product type is imported which has potential implications for the sustainability of the national feed inventory.  

Increasing forage grown per ha currently farmed is usually the cheapest means of building forage reserves; this is a strategic priority. While national data indicates some increase in the proportion of area farmed at optimal pH and nutrient status, there remains significant scope to improve annual forage output per ha before alternative sources are considered.       

Management effects on silage yield- soil fertility

Silage yield and quality are often considered as competing objectives. However, a good base of soil fertility and a well-managed reseeding programme will deliver high yields at the quality required across the year. An issue for farms with poor soil fertility is often that silage cutting gets delayed in spring in order to build a crop to adequate yield. However, as shown in  Figure 1, if soil fertility is improved then the crop will reach target yield much earlier, leading to better quality and an improved recovery for second cut.  A key step for building feed security is to build soil fertility on the farm in general, and on silage ground, in particular. Your Teagasc advisor will help you to put a good plan in place.


Figure 1. Grass yield, quality and soil fertility

Management effects on silage yield- should first cuts be delayed to deliver bulk?

A concern with targeting quality silage for first cut is potential reduction in silage yield, which may contribute to silage shortages later in the year. On this point, it is vital to consider the yield of forage DM across the year as a whole, not just from a single cut. Figure 2 shows the effect of different first-cut dates on total grass silage DM and forage energy (UFL) yield per ha, in a two-cut system with a fixed second cut date in late July.


Figure 2. Effect of first cut date on total silage DM and UFL yield in a 2-cut system

There was no advantage in total DM production to delaying first cut due to poor yield at 2nd harvest. In addition, first cut silage was lower in DMD and not suitable for growing cattle or calved milking or suckler cows. Delaying second cut further for the later first cut swards would have reduced availability of autumn after-grass and negated any silage yield benefit. In fact, many farms who delayed first cut in 2017 experienced great difficulty in salvaging second cut crops in late August and September which actually contributed to the silage shortage problem. Low soil fertility may exacerbate this problem due to slower recovery and increased delay to 2nd cuts. From a cost perspective, delaying first cut would not result in significant dilution of land charge (due to similar total DM yield per ha), while contractor costs would be similar (particularly on a bale silage system). Management decisions around first cut silage yield should therefore be made on the basis of meeting DMD targets and improving annual grass tonnage per hectare, rather than focussing solely on the bulk of an individual cut.    


Establishing feed reserves can require a significant cash outlay. At recommended volumes and a moderate forage unit cost of costs of €160-180/t DM,  a standard dairy herd would need to invest €80-€140 per cow for no increase in milk revenue. However unlike purchased feed that is utilised within-year, the reserve is retained as stock inventory and so is largely profit-neutral. The cost of building a feed reserve highlights a need to closely examine the economics of increasing herd scale based on conserved forage and concentrates.

Fodder Feed Space

Having adequate fodder storage space is a critical element of managing feed reserves on a year-on-year basis. Level of investment in this aspect of farm facilities has been relatively low in recent years, despite significant increases in dairy herd size in particular. Teagasc recommend that forage storage costs be factored into any farm development plan where annual feed demand is increased. 

For further advice you can contact any of our Teagasc offices using this link Teagasc Advisory Regions here  

This article featured in the Today's Farm Magazine. Today's Farm is a Teagasc publication. If you liked this article, you might like others in this publication Today's Farm (May/June) here