Silage Inoculants – Investment or Expense?

September 1, 2014

Silage Inoculants – Investment or Expense?

There is a tendency to undervalue silages, both in terms of feed value and the true costs of growing and ensiling them.  Consequently, many farmers do not pay enough attention to making and using them for maximum benefit.

The cost of land has to be included when calculating growing costs.  If debt free, then opportunity costs should be used, or if purchased using a loan, then the debt servicing costs need to be covered.  Land valued at $30,000 per hectare, using an interest rate of 7%, would add 16 c/kg DM to the cost of pasture, assuming a yield of 13 tonnes DM per hectare.

Costs such as those associated with reseeding, fertiliser purchase and application, pest control, drainage, irrigation and topping also need to be included, which could add another 5-10 c/kg DM.

The costs of harvesting and ensiling silages depend on whether farmers make their own silages or use contractors, which can add about 5 c/kg DM.  Feeding out costs also needs to be included, and could add a further 5 c/kg DM.  The net result is silages are not cheap feeds.

Silage making and utilisation is about minimising losses, as these occur at every stage of the process from harvesting, through ensiling to feeding out.  Losses can typically vary from 5 – 25%, due to ensiling and feeding out.  Taking the worst case scenario, then silage costing approximately 30 c/kg DM to produce and feed, ends up costing about 40 c/kg DM consumed.

Feeds purchased for $350.00/tonne (at 92% DM), for feeding during periods of pasture shortage, work out at 38 c/kg DM, assuming no wastage, and excluding costs of feeding.  Although the costs may seem similar, bought in feeds need to be purchased from cash flow, whereas most of the costs of making silage are from fixed costs.  Therefore, it is more profitable to feed silage than a bought in feed in this example.

Minimising costs requires each stage of the process to be performed as efficiently and effectively as possible, and silage inoculants should be part of this process.  High quality inoculants, containing both bacteria and enzymes, have been demonstrated to: reduce ensiling losses through faster fermentation; produce more stable silages resulting in lower losses through aerobic deterioration; increase palatability; and increase the efficiency of utilisation of nutrients resulting in better production.  Typically quoted return on investment figures for high quality inoculants tend to be about 2-3:1.

As featured in NZ Dairy Farmer

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