To grow or not to grow

High demand and short supply have caused prices for bought in maize to start rising. As a result I am often asked “Is it better to grow maize on farm, or to buy it in?”

With a milk price sitting at $6.75/kgMS things are looking good for this season. But in the last few years we have learnt two things: one, milk price is prone to fluctuation and, two, farmers need to control expenses, a big part of which can be their supplementary feed bill.

Growing maize silage on farm is an excellent way to provide lots of high-quality dry matter at a keen price.

It is common for farmers to be able to grow maize silage crops on paddocks that need renewing, yielding 18-24 tDM/ha for about 16-21c/kgDM in the stack. Growing costs can be reduced even more by growing maize in an effluent paddock where mostly there is no need for extra fertiliser. This drops the cost of maize to 12-18c/kgDM -- attractive compared to buying in maize silage for, say, 28-34c/kgDM.

However, my analysis above doesn’t tell the whole story; there are a few things you also need to think about.

Firstly, does the area where you want to grow your maize truly need renovating? Because if the paddock is already producing a lot of dry matter, the difference in the total amount of dry matter grown by putting in a crop of maize needs to be considered.

Take the example of a poorly performing paddock growing 9tDM for the year, but that would grow 27tDM if planted in maize plus new grass.

The benefit of the maize system is 18tDM (27-9).

If it costs $3800/ha to grow, then this extra feed has cost 21c/kgDM. However, if the paddock doesn’t need renewing and is now growing 14tDM/ha, the net amount of feed grown on the paddock is only 13 tDM/ha and the cost of that feed rises to 29c/kgDM.

At this price it is better to buy it in as you are paying for someone else to take the risk.

Secondly, what is the chance of your achieving the yield you have planned for? For example, on very wet land or very dry land the yields can vary greatly depending on the season. This has a big impact on the profitability of your farm system: either you may not get the amount of feed you need or the actual price of your home grown feed could be very high if your yield is low. In other words, the risk of growing on farm outweighs the benefits of getting cheaper feed. If this is the case, it is better to buy your maize in.

Thirdly, are there areas of the farm needing to be cropped to solve a problem? For example, your effluent or night paddocks may have high K levels causing milk fever problems in early lactation.

A crop of maize will solve this easily. In this case it is likely you won’t need any fertiliser to grow your maize.

This can bring the average cost per hectare from down from about $3800/ha to $2800/ha. Using the example in my first point, the cost of feed of the extra feed grown on the effluent paddock is 22c/kgDM ($2800/ha ÷ 13tDM/ha). At this price you would be likely to grow onfarm.

Lastly, many farmers simply can’t grow enough feed themselves and so need to buy in some maize to top up their home grown maize. Let’s say you need 200tDM but can only grow 100tDM on your effluent paddocks. The local grower is offering maize silage at 32c/kgDM landed. If we assume the feed you grew has cost you 22c/kgDM (as per the previous example), then the average cost of the whole 200tDM will be 27c/kgDM. This is a saving of about $10,000.

In summary, as I have tried to show, it is important to run the numbers on your farm, taking into account all the factors you need to consider in making that decision. If you are unsure of how to generate those numbers you can either ask our Pioneer team to help (call 0800 746633) or ask your consultant to help you run the numbers.

• Ian Williams is a Pioneer forage specialist. Contact him at This email address is being protected from spambots. You need JavaScript enabled to view it.