Twenty multiparous lactating Holstein cows in early lactation were used to
investigate effects of exogenous fibrolytic enzyme supplementation on dry m
atter intake, milk production, and digestibility. Cows were blocked accordi
ng to parity, expected calving date, and milk yield in the previous lactati
on, and then randomly assigned after calving to two treatments: control or
enzyme. The enzyme mixture, which contained mainly xylanase and cellulase a
ctivities (Pro-Mote(R), Biovance Technol. Inc., Omaha, NE), was added to th
e concentrate to supply 1.3 g/kg of total mixed ration (dry matter basis).
The total mixed rations contained 24% corn silage, 15% alfalfa hay, and 61%
barley concentrate (dry matter basis) and were offered for ad libitum inta
ke. Enzyme addition did not affect dry matter intake. However, total digest
ibility of nutrients, determined using Cr2O3, was dramatically increased by
enzyme treatment (dry matter, 61.7 vs. 69.1%; neutral detergent fiber, 42.
5 vs. 51.0%; acid detergent fiber, 31.7 vs. 41.9%; crude protein, 61.7 vs.
69.8%). Consequently, milk yield tended to increase (35.9 vs. 39.5 kg/d). P
ercentage of milk fat was lower, and percentages of milk protein tended to
be lower for cows fed a diet supplemented with enzymes, such that component
yields were similar for cows fed either diet. Energy deficiency was numeri
cally lower for cows fed a diet supplemented with enzymes than for cows fed
the control diet (-3.62 vs. -3.33 Mcal/d). Supplementing dairy cow diets w
ith a fibrolytic enzyme mixture has the potential to enhance milk yield and
nutrient digestibility of cows in early lactation without changing feed in
take.