Forage maize for dairy cows
Michael Garvey, Dairying Development Adviser, CAFRE, Armagh
There was a large group of farmers at the recent CAFRE Alternative Forages short course on the farm of Henry Johnston, Armagh.
Henry’s maize crop was drilled into a fine seed bed in early April and covered with plastic. Crop management was geared to producing a high dry matter / high starch combination that would have a positive effect on milk production.
His target was to produce maize silage with 30 percent dry matter and 30 percent starch content.
Maturity of the crop had been monitored regularly since early September. Even at that stage, it appeared to be maturing well. Henry planned to harvest when the combined plant and cob dry matter was at the target of 30 percent dry matter.
On the 5 October samples of the crop were analysed for dry matter and the average result was: -
| Cob DM % | Stover DM % | Plant DM % |
|---|---|---|
| 47 | 20 | 30 |
Harvesting of the crop began on Monday 11 October.
Trevor Gilliland of the Agri-Food and Biosciences Institute (AFBI) Crossnacreevy spoke to the group on a number of key points to consider when growing forage maize:
- Select varieties from The Forage Maize Recommended Varieties booklet.
- The extra yield achieved using plastic mulch for early establishment justifies the expense.
- Oversupplying nutrients above the RB209 recommendations does not give an increase in yield and delays crop ripening.
In discussion with local CAFRE adviser Michael Garvey, highlighted the practical steps that farmers should take to assess crop readiness for harvest: -
- Plants selected for examination should reflect the overall crop in the field.
- Husks should be yellow and papery to the touch.
- Grains on the cob should resist pressure from the thumb nail, they should be loose on the core, deep yellow in colour and potentially glazed.
- Squeezing the grain should produce no liquid and there should be starch present.
- The plant stem should produce little sap when broken and doubled over.
Senior CAFRE adviser Alan Hopps outlined the relevant issues at ensiling and feeding: -
- Maize silage harvested at 30 percent DM has the greatest influence on forage intake and milk yield when fed with grass silage
- The grains should be passed through a corn cracker in the harvester to aid subsequent performance as a cow feed.
- Clamps should be narrow and well compacted. Short chop length aids compaction.
- A 100 cow herd will need 7ha of forage maize at 30 percent dry matter to allow “50:50” feeding with grass silage over a 180 day winter.
- The ration will need balanced to give an overall crude protein of 17 - 18 percent in the cow diet in early lactation. This will involve increasing the percent protein in the concentrate.
- There will be some benefit in having a fibre based concentrate
After seeing the Johnston maize harvest in progress, this group of farmers are now better placed to assess their own crop maturity and time it’s harvest to coincide with the 30 percent dry matter, 30 percent starch targets.
Michael Garvey CAFRE Dairy Development Adviser and Trevor Gilliland, AFBI, Crossnacreevy discussing maize crop maturity on Henry Johnston’s farm, Tynan
Local contractor William Irwin, harvesting forage maize for Henry Johnston, Tynan on 11 October 2010
