Higher corn silage diets: Why do many nutritionists prefer them? – Dr. Darin Bremmer, Vita Plus
What once was considered a high corn silage diet is not high compared to today’s standards. In the past, you never heard of feeding milk cow diets containing more than 50 percent of forage dry matter (DM) from corn silage. We now feed diets with more than 80 percent of forage DM from corn silage.
It is easier to harvest one crop of corn silage than to harvest three to five cuttings of haylage. Every cutting of haylage can lead to a completely new adventure depending on quality and fiber digestibility. When a high corn silage diet is dialed in, very few changes are required.
Herd growth has increased the amount of corn silage in milk cow diets. Economics push us to harvest greater amounts of DM per acre. Corn silage is our highest-yielding forage, producing at least 8 tons of DM per acre while alfalfa yields struggle to get to 5 tons of DM. Winterkill and drought have added to our frustration with alfalfa, however, we have been able to rely on corn silage to consistently supply the forage required to balance milk cow diets.
Many people believe corn silage-based diets are more expensive than alfalfa-based diets because more supplemental protein is fed as corn silage increases. There is more to balancing high corn silage diets than just adding protein.
Corn silage contains starch, so less corn grain is fed. Another benefit is that less expensive protein sources containing more rumen degradable protein (corn gluten feed, canola meal, soybean meal) and urea can be fed instead of more expensive rumen undegradable protein sources (blood meal, heat treated soy products). We can rely on microbial protein for milk production rather than forcing expensive rumen undegradable protein to the intestine. When you add in that it costs less to produce corn silage than alfalfa haylage, high corn silage diets are more economical than higher alfalfa-based diets.
The table below compares the costs of higher corn silage diets. The five diets range from 60 percent to 93 percent of forage DM from corn silage. As the amount of corn silage increases, the amount of ground corn decreases and the protein sources increase. The last row compares the costs versus the 60 percent corn silage diet. There are significant savings as corn silage increases.
There are many considerations when moving to higher corn silage-based milk cow diets. Consistency and economics of high corn silage diets make corn silage attractive to both nutritionists and producers. This article addresses reasons why nutritionists like high corn silage diets, but it does not consider agronomical issues that may be specific to your farm or climate.
Feed quality and nutrition