Back Stored verses grazed forages

Date: 05 May 2017

The last season has been one of the most difficult I have ever experienced. A cold wet spring meant many maize crops were planted late. This has happened in the past but hasn’t really been a problem as the warm summers that often follow a cold spring have meant that the maize has caught up and have therefore been harvested on time.
This summer however was cooler than normal and it meant that many crops that got planted late, stayed late. Once again, a warm autumn would normally mean that though the crops would be late, they wouldn’t be too late. However, just as harvest had begun we got hit with two cyclones which meant harvest was delayed even further. Some maize has been harvested quite dry. Contractors have done an excellent job chopping it short and ensuring there has been enough tractor weight on the stack to get the necessary compaction given the crops’ dryness. As I write, most crops have now been harvested and are safely in the stack ready to be fed out to dairy cows.

Great autumn:
Fortunately, the late harvest of the maize crops hasn’t been a problem on most dairy farms as the cool summer and then the wet autumn has meant there has been more than enough grass around. On many dairy farms milk production is holding up and cow condition is reasonable. This has meant that many farmers will be able to milk well into late May.

Feeding maize in late lactation and during the dry period:
Given the above scenario, knowing when and how to feed maize is critical. There are a few things that you need to remember in order to turn as much of this feed into milk as possible. These are:

  1. Only feed your silage if you really need it. If you don’t have a feed deficit, leave the stack un-opened until you do. If the maize silage has been harvested and stacked properly, it will remain as good as the day it was ensiled until you start feeding it.
  2. Once you open the stack, ensure that you manage it well. This means keeping the face very tight, no fluffing it up when you are unloading. Try to get across the face at least every second day. Ensure that any loose material in front of the stack is cleaned up after the feeding has been done.  Make yourself a stack face cover from wind cloth or bird netting to stop the birds pulling down loose material.
  3. Use maize to build pasture cover in preparation for calving. Feeding maize in late lactation/early dry period is a great way of building pasture cover levels to what you want at calving. Once these levels have been achieved, it is easy to manage them through spring by either speeding up or slowing the round down depending on what the winter delivers.
  4. Use maize silage to achieve your target body condition scores (BCS). These are as follows:  mature cows - BCS 5.0; and first and second calvers - BCS 5.5.  There has been some thought in recent years that if your cows gain weight too quickly during the dry period it will have a negative effect on production, reproduction or animal health. A trial done a couple of years ago by DairyNZ looked at the issue and they found that there was no difference in milk production, reproduction or cow health in cows that gained weight at different rates. So, it doesn’t really matter how fast or slow they gain weight, if your cows are below their ideal BCS, maize silage is a wonderful feed for putting weight on cows.

There is one final thing that has impressed me this season.  Despite the difficulties I outlined above, maize silage has still shown its versatility. In my opinion, it has to be one of the best farm systems feed available to farmers.

 

Ian Williams

Forage and Farm Systems Specialist