Spring may still be a few months away, but now’s the time to prepare for “spring acidosis,” a phenomenon that occurs in many herds as winter fades into spring.

The symptoms of spring acidosis include loose manure, a decline in feed intake and depressed milk-fat test. These symptoms seem to occur most often in herds that feed more than 15 pounds of corn silage per head (on a dry matter basis), combined with high-moisture corn in excess of 26 percent moisture, says Bill Mahanna, global nutritional sciences manager with Pioneer, a DuPont Company.

Research from the University of Nebraska shows that as kernel moisture and length of storage increase, the starch in the high-moisture corn becomes more digestible in the rumen.  European studies show this also occurs in the kernels of corn silage. This increase in starch digestibility may explain why producers see increased symptoms of acidosis in the spring, Mahanna says.

Prepare now to minimize the effects of spring acidosis. Mahanna offers these strategies to help you do so:

  • Don’t vary high-moisture corn inclusion rates based on forage quality alone.  Account for the increased energy available in long-stored, wet high-moisture corn during ration balancing.
  • In spring, lower the inclusion rate of the wetter high-moisture corn in favor of more corn silage, or possibly replace some of the high-moisture corn with dry corn.
  • Consider adding 1 to 2 pounds of straw to the ration to help develop the rumen mat and stimulate cud-chewing, which helps buffer the rumen. Adding buffers to the ration also can help.
  • Monitor changes in ruminal starch digestibility. To do so, pull samples of both corn silage and high-moisture corn at 60 days ensiled. Freeze them. Pull samples again at 150 to 200 days ensiled. Send both sets of samples to a lab that offers a starch-digestibility analysis. Here are two labs that offer this test: Dairyland Laboratories, Arcadia, Wis., (608) 323-2123; and Cumberland Valley Analytical Services, Hagerstown, Md., (800) 282-7522.

Source: Bill Mahanna, Pioneer