The proper handling and storing of corn silage is one of the main drivers for increased milk production.
Tony Hall with Lallemand Animal Nutrition in New York state outlined key points to ensiled forage at the recent 2019 Dairy Symposium put on by Grand Valley Fortifiers.
Why it matters: Milk production directly relates to feed intake and feed quality. Storage plays a huge role in the final product of feed and therefore, milk production.
Dairy feed quality is measured by the dry matter content, fermentation speed, nutrient retention, the presence of moulds or wild yeasts and many other factors.
There are four critical areas that require attention to ensure proper harvesting and storage to help increase the milk production: time of harvest, processing of harvest, ensiling and maintaining quality in the silo.
Time of harvest
If corn silage is harvested too early, dry matter content can be lost.
Large amounts of seepage can occur if the crop is harvested too early and ensiled. A farmer can lose 50 per cent of their “silage juice” in the first week, says Hall, and 25 per cent in the two weeks following, and it continues for up to eight weeks post-harvest — total dry matter loss can be up to six per cent with this seepage.
On the other hand, when harvesting silage too late, the dry matter can rise to more than 39 per cent. Issues with packing can occur and the feed can have low digestibility.
If the silage is harvested too dry, there is an issue with the packing density and porosity of the silo, wild yeast activity and the concern of moulds developing in the feed.
Processing at harvest
Use of kernel processors has shown an increase in milk production and corn kernels digest in the rumen better compared to corn silage without the use of a kernel processor. Hall has found that cattle fed corn silage that was processed had fewer corn kernels in their manure, indicating more thorough digestion in the rumen.
A study completed by Bal et al. in 2000 in Wisconsin showed that cattle fed kernel processed corn silage gave on average 1.2 kilograms of milk more per cow per day than those that were not fed a kernel processed feed. These same cattle fed the kernel processed corn silage had a greater dry matter intake by 0.6 kg per day and a higher fat content of 0.7 kg per day.
When packing the bunk, the density is of extreme importance. If it is not packed dense enough, there is an excess of air and a loss of nutrients.
Hall mentioned a study completed in 1992 by Ruppel outlining the issues of incorrect bunk packing leading to a loss in nutrients.
A bunk silo packed at 10 pounds of dry matter per cubic foot has a 23 per cent dry matter loss, which is 13 per cent more loss than silos packed at 20 lb. of dry matter per cubic foot.
To ensure proper packing density, the tractor needs to be the proper weight. For example, if getting a yield of 30 tons per acre and harvesting 100 acres in 10 hours, the multiple tractors would need to weigh 240,000 lbs., whereas on the other end of the spectrum of harvesting 15 tons per acre and 25 acres in 10 hours the tractor would need to weight 30,000 lb.
It’s important to ensure no moulds or fungi develop in the corn silage silo. It’s imperative to plant hybrids resistant to insects and diseases, ensure the proper tillage practices are being used, be aware of mycotoxins and ensure proper storage in the silo.
Wild spoilage yeasts can be a concern under aerobic conditions. They will use substrates, sugars, lactate, malate, citrate, propionate and ethanol to reproduce and grow, says Hall.
“The silage being exposed to air “wakes up” the yeast and they begin to degrade the residual sugars and then move onto the lactic acid to reproduce. As the populations increase, highly degradable nutrients are destroyed,” says Hall, with a 50 per cent dry matter loss. Heat is produced, pH increases and mould and bacteria begin to grow causing massive spoilage and potential toxin production.
Corn silage needs a low yeast level to maintain the aerobic stability — aerobic stability is directly related to the yeast levels.
An improvement of storage and handling of daily feed has a direct correlation to the improvement of milk production.