Maize is more than just a supplementary feed

Consumers want to eat food that is ethically produced and manufacturers want products they can use to make products they can sell.  And, farmers still need to make a profit and have enough time to enjoy the fruits of their labour. 

The key issues farmers will face this year are:

1. Feeding cows in a Fat Evaluation Index (FEI) constrained environment.

2. Reducing N and P loss on farm (and potentially greenhouse gas losses).

3. Making money and paying off debt to increase comfort levels when the next downturn occurs. 

Choosing the right supplement to enable farmers to deal with each of these challenges is a complex decision. As well as balancing feed price and nutrient composition with cow nutritional requirements and likely financial benefits, farmers must also consider how the supplement fits into their dairy farm system, and its impact on the environment. They also now need to consider what the impact of the supplement will be on their FEI.

While maize silage provides an excellent nutritional profile and can be grown or purchased at a cost-effective price, it is more than just a supplementary feed. That’s because growing and feeding maize silage delivers a number of unequalled farm systems and environmental benefits. These include: 

1. Feeding maize to prevent the FEI from getting in the C and D regions. 

Many farmers have been watching the FEI quite closely this season as it is likely to become an issue for next season.  While it appears that certain feed types cause the FEI to rise, others seem to have no effect.  Feeds that appear to lift the FEI into the danger zone are PKE when fed above 3kgDM/cow/day, some brassicas and some beet.  Maize silage, on the other hand, seems to be having no impact on raising the FEI, so many farmers are now feeding maize silage and maize grain in place of PKE. 

It also appears that cows which lose weight rapidly also are in danger of driving up the milk FEI.  This was the case on some South Island dairy farms this spring post-calving, when cows lost a lot of weight coming off their winter fodder beet paddocks.  Farmers who used maize silage as part of their transition diet didn’t seem to experience the same problem as those who transitioned straight from beet to grass.

2. Growing maize on effluent paddocks to increase environmental benefits and produce low-cost feed 

Farmers in many areas across New Zealand are now being required to reduce their N and P loss. Maize silage is set to become a key tool in this process. 

Maize is a deep-rooted crop that can extract water and nutrients from depths two-three times greater than typical pasture species including ryegrass and clover. Because it has a high demand for nitrogen (12kgN and 10kgK for every 1tDM removed), it can be used to remove excess N and K from effluent blocks. This reduces the risk of nutrient leaching and lowers the chance of milk fever caused by feeding high potassium pasture to springers.

A two-year on farm study showed that maize silage crops grown on effluent paddocks with no additional fertiliser (no base, starter or sidedressing) yielded an average of 26.1tDM/ha. Without the need for additional fertiliser, silage drymatter costs are significantly reduced (Table 1). 

3. Feeding maize silage to reduce cow urinary nitrogen levels 

Pasture frequently contains excess crude protein (nitrogen) relative to animal requirements. A high proportion (typically 60 - 70%) of the excess nitrogen intake is excreted in the urine. Urinary nitrates can be relatively quickly leached beyond the reach of shallow-rooted pasture plants. Feeding maize silage (a low protein feedstuff) dilutes dietary protein content and reduces nitrogen loss from the cow. 

4. Feeding maize on stand-off/feedpads can help grow more pasture 

While most forage crops must be fed out when mature, a key benefit of maize silage is that it can be stored long-term and fed when needed. Last winter proved to many farmers the benefit of having a feed pad on pasture production. The combination of maize silage and a well-designed stand-off pad with feeding facilities allowed farmers to keep cows off wet pastures, decreasing pugging without compromising production or animal welfare.

Maize silage fed on a feed pad also prevents cows from over-grazing pastures, ensuring they persist.  

This was clearly the case three years ago during a very dry summer.  Farmers who had a feed pad and were able to stand cows off paddock and feed them reported that their farms came back very quickly once the rains came, simply because they hadn’t over-grazed their pastures.

5. Maize silage allows farmers to fill feed gaps profitably, meaning more profit to pay down more debt 

While there has been much discussion over the previous two seasons on de-intensification of systems, over the last 11 years, on average, high input farms have made more profit per hectare, had higher return on asset and equity and have had a similar risk profile (see table 2) to low input farms.  This extra cash enabled the farmers to either invest more capital (in shares, cows, infrastructure) or pay off debt.

¹Pioneer Maize Silage 2017-201 page 33. The value of pasture lost during the maize growing season has not been considered in the calculation of the maize silage drymatter cost.

²Assumes no base, starter or sidedress fertiliser is required.