Providing both digestible fiber and energy (starch), corn silage is a primary forage source for many dairy farms around the world. But there can be complications to feeding this highly used raw feed source. The North America Dairy Team at Novus International is providing advice to the industry on how to avoid dips in dairy production during this seasonal transition.
Transitioning to a new crop of corn silage has been shown to negatively impact dry matter intake, milk, and milk component production in dairy cows. This is because partly fermented silage can upset the normal activity of rumen bacteria and promote sub-clinical acidosis, leading to reduced intake and production.
Under ideal conditions, corn silage completes an initial fermentation phase in three to four weeks, however, better results are seen when feeding silage that is allowed to ferment in the silo for six to eight weeks.
Time is only one factor impacting fermentation. In a bunker silo, variations can occur in silage moisture and nutrient content depending on the location of the corn from the sloped edge of the bunker to the main part of the corn pile. This too can create unstable fermentation conditions ultimately resulting in reduce intake and milk component yields.
To avoid these impacts on dairy production, the North America Dairy Team at Novus created guidelines for feeding newly ensiled corn silage:
- When using silage that has not been allowed to ferment in the silo for at least three weeks, introduce it gradually over two to three weeks.
- Test the dry matter content of the new silage two to three times per week, adjusting the ration batch feeding schedule to provide a constant amount of dry matter in the diet.
- A forage analysis (dry matter, neutral detergent fiber (NDF), starch, pH level, and NDF digestibility) will show where to make necessary adjustments.
- If possible, reduce the total amount of corn silage being fed until dry matter intake, manure consistency, and the rate of passage of the diet are stable.
- Add one to two pounds of grass hay per cow/day to slow the rate of passage through the rumen/reduce diarrhea.
- Corn silage contains approximately 2% unsaturated fatty acids, which can contribute to diet-induced milk fat depression. Using a feed additive containing methionine source HMTBa (commercially known as MFP® feed supplement) in the diet at 0.12% of dry matter is shown to help maintain milk fat and protein output by stabilizing normal rumen metabolism of unsaturated fat even during changes in the diet. Supplementing with MFP® is repeatedly shown to minimize the risk of diet-induced milk fat depression.
Dairy producers can’t always count on corn silage to be at the ‘right’ phase of fermentation before feeding it to their cows. Following these guidelines can help reduce the impact on milk and milk component production when transitioning to a new silage crop.