Feeding maize silage in winter: Setting the herd up for success
As I write this article, we have just had our first frost in the Waikato, a change in weather signalling that winter is upon us.
The process extends the shelf life of the pasture beyond what it would have if exposed to open air. To produce high-quality silage, both the quality of the original pasture and the fermentation process are crucial. Ensuring optimal dry matter content, rapid wilting, proper compaction, and effective sealing can help retain the nutrients and feeding value of the silage. It’s essential to feed out silage quickly once exposed to air to prevent spoilage.
It is impossible to produce high quality silage from low quality pasture, no matter how good the fermentation is. Both the quality of the ensiled pasture and the quality of the fermentation must be considered.
When pasture is ensiled, its sugars are converted into lactic acid by bacteria. It is the lactic acid which pickles the pasture, allowing it to be preserved for a lot longer than it would have been if left in the open air.
With well-preserved silage, losses in feeding value during fermentation will be small, and the final silage will be only slightly lower in feeding value than the original pasture.
Good quality pasture silage is a good source of energy and protein for a milking cow and can be used as a fibre source when feeding high sugar or starch feeds. However, a poor-quality pasture silage (made from low quality pasture, or ensiled with low quality fermentation, or both) will not support high milk yield and will only be suitable for dry cows, or as a fibre source to reduce risk of acidosis.
Losses when making pasture silage
Losses occur as sugars and protein in the grass is broken down by enzymes, and bacteria. This process starts as soon as the grass is cut. Losses decrease quality as well as quantity, because it is the highly digestible components which are most rapidly broken down.
Losses during harvesting
Losses depend on the dry matter (DM) of the pasture. The optimum DM for silage is 25-30% because total DM loss is minimised.
- Cut in the morning of a sunny day, for rapid wilting. Cutting after 1-2 days' sunny weather will result in good sugar levels in the pasture, even when cut in the morning.
- Avoid wilting for any more than 24 hours.
- Compact the silage well. In a stack or pit, use the heaviest wheeled vehicle available.
- Tractor wheels should not sink into the pile of pasture any further than the depth of rubber.
- For baled silage make sure that a high density baler is used.
- Seal the stack completely with a weighted, airtight cover. Wash old polythene before use to avoid contamination with the wrong bacteria.
