A one-day change in ration dry matter can have a big impact on milk production, say researchers at the U.S. Dairy Forage Research Center in Madison, WI.

They changed forage dry matter one day a week to simulate a rainfall event on a bunker silo and the feeding of an imprecise ration based on as-fed ratios of ingredients.

A control ration was adjusted to maintain constant dry matter ratios of ingredients on that day.

Each period consisted of three days to establish a baseline, one day of ration differences (day four) and three days of recovery. The ration changes were repeated five times by changing the dry matter of corn silage, alfalfa silage or both by eight percentage points.

On day four, the dry matter intake of treatment cows was reduced by 4.9 lbs/cow compared to baseline, and their production was down by almost 2 lbs/day on days five and six.

The researchers concluded that “improving ration precision by adjusting rations for forage dry matter changes enhances dry matter intake and milk production.”