Are You Considering Forage Maize?
Richard Henning Dairying Development Adviser Newry
Alternative forages such as wholecrop wheat and forage maize for use on dairy farms have become more popular in recent years. Some of the reasons for this are:
- Improved dry matter intakes
- Increased milk yield and compositional quality
- Provides a clean seed bed for under-sowing or autumn reseeding (wholecrop)
- High forage yields from a small area.
Before considering an alternative forage, dairy farmers should ask themselves if they are achieving full potential from their all-grass system. Well managed grass/grass silage systems have the potential to produce excellent results as evidenced on many dairy farms.
Growing a successful maize crop
- Site selection – choose a sheltered field with free draining soil
- Variety selection – choose a balance between the ability to fully mature under conditions that are seldom ideal without sacrificing yield potential. The recently published recommended list (available in your local Agriculture Development Centre) will provide guidance on the best variety for individual farm circumstances. Ultimately yield will determine the cost of the crop – low yields result in high costs per tonne of dry matter.
Arable Aid is no longer available and benchmarking results suggest that maize has to yield approximately 13.4 tonnes DM/ha to compete with quality grass silage. In trials at Crossnacreevy the average over the last four years has been 12.5 tonnes DM/ha without plastic. This yield is unlikely to be achieved, in all areas of the country and therefore leaves the growing of forage maize marginal.
However, trials at Crossnacreevy indicate that ME, yield and starch content are improved by using plastic mulch. These gains are deemed to compensate for the additional cost of plastic.
Table 1
Maize Performance with and without plastic mulch
| Silking Date | Total Yield to DM/Ha | DM | Starch Content | ME Content MJ/KG | |
|---|---|---|---|---|---|
| Plastic | 31 July | 16.2 | 32.6 | 36 | 11.1 |
| Open Establishment | 19 August | 12.5 | 30.2 | 26.8 | 10.6 |
Source: Plant Testing Station, Crossnacreevy
Will an alternative forage improve profit?
The overall advantage to growing alternative forages has not been fully established. Indeed some of the benefits are intangible or at best, very difficult to financially quantify. Whilst research has shown that good quality maize silage (30 percent DM, 30 percent starch) can boost milk yield and milk protein content, the most recent Greenmount Dairy Benchmarking Report does not identify significant based system advantages of either maize or wholecrop silage over a good grass and silage.
Results form a sample of dairy farmers using either of those secondary forages would indicate that while milk yield on these farms was higher by an average 800 litres/cow, no improvements were seen in milk components. Meal feeding was also 300 KGs per cow higher on farms feeding maize and wholecrop.
On the financial side it would appear that secondary forages increase costs significantly due to establishment using plastic mulch and harvesting. In addition the quantity and quality of concentrates used to balance these attendance forages added to the costs per litre of milk produced. Overall no consistent effect is evident in terms of net profit/cow.
In summary
- In marginal areas maize grown without plastic will struggle to compete with a grass silage system.
- Quality maize silage can boost milk yield and protein content.
- Net profit is not guaranteed of increasing with alternative forages.
- Other ‘perceived’ benefits such as cow health or slurry utilisation are difficult to quantify.
