A MichiganState analysis shows a more fermentable diet reduces fat-corrected milk yield of cows fed corn distillers grains.

Milk yield of cows declines with increasing dietary corn distillers grains when diet fermentability increases. That was the conclusion of a MichiganStateUniversity analysis of 27 studies in 23 published research articles. The analysis shows that forage type, grain concentration and grain fermentability — all factors that affect how fermentable the diet is — influence a cow’s production response to corn distillers in the ration. Here is a snapshot of the conclusions:

  • Corn-distillers-supplemented diets containing corn silage as the only forage source, resulted in lower fat-corrected milk production than diets containing more than 80-percent alfalfa as the forage source. Milk response was intermediate for diets containing a mixture of the two forages.
  • Cows fed a diet containing distillers grains produced less fat-corrected milk when the concentration of corn grain in the diet was greater than 20 percent of total dietary dry matter compared to a corn-grain concentration of less than 20 percent.
  • Distillers-supplemented diets that contained high-moisture corn compared to dry corn resulted in lower fat-corrected milk yield.

These findings strongly suggest that inclusion level of corn distillers grains is dependent on and limited by ration forage type, grain concentration and grain fermentability.

“We think this is quite important information about feeding corn distillers grains to lactating dairy cows and explains some of the problems (poor responses relative to expectations) that are occurring out in the field,” says Dave Beede, professor of dairy nutrition at Michigan State.

Source: Journal of Dairy Science, Vol. 90, Suppl. 1, Abstr. #651, 2007