Gycerol may have a new use in lactating-cow rations, thanks to soy biodiesel production.

Researchers at PurdueUniversity used glycerol to replace corn as an energy source in lactating-cow diets.

One diet contained no glycerol. In three other diets, glycerol made up 5 percent, 10 percent or 15 percent of ration dry matter. The researchers replaced corn with an equivalent amount of glycerol and corn gluten feed. The latter was used to replace the protein lost when corn was removed from the diet, says Shawn Donkin, professor of ruminant nutrition and physiology at PurdueUniversity.

Overall, the study found no difference in dry matter intake or milk yield (please see the table below). Milk composition also did not vary between treatment groups.

 

             Glycerol level

             (percent of dry matter)

 

0

 

5

 

10

 

15

 

Milk
production (lb/day)

 

81.4

 

81.2

 

82.1

 

80

 

Feed intake
(lb/day)

 

52.8

 

53.9

 

54.1

 

53

 

 

Source: 2007 Tri-State Dairy Nutrition Conference