With silage season kicking up a gear, consider measuring the volume of silage you've made to date and estimating how much more you'll need to get you through the winter.

What’s in reserve?

Figure 1 outlines the measurements (length/width/height) needed to calculate tonnage in a silage pit. Take measurements in feet and multiply A x B x C. Divide the final figure by 45. Where the silage is single-chopped, divide by 50 as silage will not be as compacted.

Alternatively, assume that poor-, average- or good-yielding first-cut silage will produce seven, eight or nine tonnes per acre, respectively. With second-cut, assume three, four or five tonnes per acre for poor-, average- or good-yielding crops. It must be stressed that getting the measuring tape out is a far more accurate method for quantifying what’s in the clamp.

Those making bales can use Table 1 to calculate each bale’s equivalent weight as 25% dry matter pit silage. This will depend on the length of the wilting period and the weather at harvest. Bales mowed and cut on the same day in relatively dry conditions will have a dry matter of 25%. A 24-hour wilt will lift this figure to 30%, while a 48-hour wilt in hot sunny weather will produce 40% dry matter bales.

What is required?

Once silage stocks are known, calculate what exactly is needed on a per head basis each month. Table 2 outlines the amount of silage required for each individual livestock class, monthly. Use the table to calculate your demand for fodder this winter. In terms of feeding period length, allow for a worst-case scenario.

So you’re showing up a deficit – what next?

You can either sell stock early or look to buy in feed. Table 3 outlines the feed options available to Irish farmers replacing fodder.

What to look for in a feed

Paying extra for a feed rich in nutrients makes better economic sense than paying pittance for a feed with moderate nutrient quality.

Shirking on quality with animal diets will depress production, potentially affect their wellbeing and ultimately hit our wallets.

Pay attention to the “cost of energy” and “supplements required” columns in Table 3. When we purchase feed we are purchasing animal performance – too often this is forgotten. In Table 3, feeds are costed on an energy basis at current prices relative to rolled barley.

Good-quality silage remains the cheapest winter fodder source we have – its energy is cheaper than that of barley and it requires no additional supplementation in many cases.

Winter feeding regimes based on beet or maize silage might seem quite cheap, but we are not taking into account the extra feeds that must be purchased in addition to these ingredients as balancers: all of these options need supplementary protein – the most expensive nutrient for livestock – with barley needing a long fibre source too.

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All the action from silage 2017