Introduction:

The objective of the study was to evaluate the effect of exogenous β-mannanase addition on dry matter intake (DMI) in the pre- and postpartum periods, milk yield (MY) and milk composition, urea nitrogen content (NU) and somatic cell count (SCC) in Holstein-Friesian cows.

Method:

Thirty cows were used in the study (body weight (BW)=781±83 kg; of more than two lactations) of approximately 260 d of gestation. The cows were stratified by BW and their previous MY and randomly assigned to one of two treatments: 1) Total mixed ration (corn-silage of corn), Control; and 2) Control+0.10% of β-mannanase (CTCZYME; Seoul, Korea).

Results:

In the prepartum period, DMI was similar (14.44±0.70 vs 15.66±0.70 kg d-1; p>0.05) between treatments. In the postpartum period, there were no differences (p>0.05) in DMI between the Control and the group with enzymes. On the contrary, MY was greater (42.66±1.31 vs 38.24±1.31 kg cow-1 d-1; p<0.05) in supplemented than in Control cows. The addition of β-mannanase into cow diets did not influence (p>0.05) milk composition; however, supplemented cows showed greater (p<0.05) feed utilization efficiency than Control cows. The SCC was lower (152,600±294.1 vs 1,112,6400±294.1 coliform cells per mL; p<0.05) in milk of cows that received β-mannanase.

Conclusion:

Addition of β-mannanase in corn-corn silage diets increased milk yield and decreased the somatic cell content in milk, but it did not influence dry matter intake in both pre- and postpartum periods, nor did it influence the urea nitrogen content in milk, and postpartum milk composition.

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