Is your ration ready for new crop corn silage?
With harvest underway and the seasons changing, now is the time to evaluate your rations and prepare for the transition to new crop corn silage. Changes in starch digestibility, rumen fermentation, forage quality and feed stability can all affect intake and milk production during this transition.
Here are three areas to consider as you begin feeding new crop corn silage.
Maintain rumen-fermentable carbohydrates
Ideally, new crop corn silage should have at least 60-to-90-days carryover before feeding to allow fermentation and starch digestibility to improve. However, sometimes that is not an option. Even under ideal conditions, starch digestibility will continue to increase for around five months, and if the corn silage is harvested dry, it may take a year to reach maximum digestibility. That means less starch is available for rumen fermentation when new crop corn silage is first fed, potentially contributing to losses of 3-6 lbs. of milk per cow/day.A conventional practice is to increase dietary starch, typically through dry or high moisture corn, until a similar level of rumen fermentable starch or carbohydrate is achieved. However, depending on the difference in starch digestibility between the old and new corn silages, this can end up being a large substitution and may come at the expense of dietary fiber. Reducing fiber levels can potentially increase rumen passage rate, leading to incomplete fermentation and increased risk of rumen upsets. Sugars provide another way to supply rumen fermentable carbohydrates without sacrificing fiber levels in the diet. Sucrose, the primary sugar found in molasses based liquid feeds, can help restore rumen fermentable carbohydrates at a relatively low inclusion rate. Because sucrose is rapidly and almost completely fermented in the rumen, it provides a highly available source of carbohydrate to support rumen fermentation. In comparison, ruminal corn starch digestibility can vary from 43-80% depending on the feedstuff, meaning sucrose can provide additional fermentable carbohydrates while maintaining fiber levels in the diet. Another advantage of adding sucrose to the diet is its positive effect on fiber digestibility. Sucrose has been shown to improve NDF digestibility (NDFd) and for every 1% increase in NDFd, is worth 0.33 lbs. more DMI and 0.55 lbs. more milk production.
- Don’t drop DCAD just because summer is over!
During the summer, it is common to feed additional buffers, such as sodium bicarbonate or sodium sesquicarbonate, along with potassium sources, such as potassium carbonate. These ingredients help improve rumen pH and increase the overall dietary cation anion difference (+DCAD). This has been shown to improve rumen function and milk component yields during times of heat stress when the cow is more prone to drops in rumen pH. Once the temperatures start to cool, these products are often reduced or removed from the diet. However, a higher DCAD isn’t necessarily, just a summer strategy. Research has shown benefits from maintaining positive DCAD levels around +32 meq/100g to +40 meq/100g, in the absence of heat stress, can have benefits in milk yield, butterfat, and fat correct milk yield. Maintaining a higher rumen pH is useful when transitioning between forages, especially corn silage. Supporting a consistent rumen pH gives rumen microbes a better opportunity to adapt to the new feed while maintaining the overall digestibility of the diet. Test for molds, yeast, and mycotoxins.
Every new feed comes with some uncertainty. Testing new crop corn silage for molds, yeasts, and mycotoxins before feeding can help identify potential problems before it occurs. The presence of molds and yeast can indicate poor fermentation or feed stability challenges, that may contribute to heating, reduced DMI, lower digestibility, rumen upsets and lost milk production. Toxins can create additional concerns related to cow health, immune function, and reproduction efficiency.Most commercial feed laboratories can test for molds, yeast, and mycotoxins and advise which toxins should be tested for in your area. Although these tests may represent an additional cost, identifying the problem before the feed reaches the bunk can prevent much larger losses in production and profitability, saving time, headaches, and potentially costly feeding problems.
Take Aways
Using sucrose to maintain rumen fermentable carbohydrates can help maintain fiber levels and production while new crop corn silage starch digestibility improves. Maintaining a higher DCAD in the diet can support rumen pH and production beyond summer months, while testing for non-nutritional factors like mold, yeast, and mycotoxins can help identify potential problems before they reach the bunk.
Contact your local Westway representative to learn how a liquid feed program can support your herd through new crop transitions.
