Abstract #T258

# T258
Production effects of phytonutrients alone or in combination with yeast culture in lactating dairy cows.
J. Oh*1, M. Harper1, A. Melgar1, E. Wall2, A. Hristov1, 1The Pennsylvania State University, University Park, PA, 2Pancosma, Geneva, Switzerland.

As rumen modifiers with distinct modes of action, yeast and phytonutrients may have additive effects on ruminal fermentation and animal productivity. To test this concept, an 8-wk, randomized complete block design study with 36 Holstein cows (average days in milk, 117 ± 37.5 d; average body weight, 651 ± 83.3 kg) was conducted to investigate the effects of a blend of phytonutrients alone or in combination with Saccharomyces cerevisiae-based yeast culture product on feed intake and milk production and composition. Cows were housed in a free-stall barn equipped with Calan Feeding System for monitoring individual feed intake. Following a 2-wk covariate period, cows were blocked in blocks of 3 based on days in milk, milk yield, and parity. Cows within a block were randomly assigned to one of the following treatments (12 cows/treatment): 14 g/cow/d yeast culture (YC), 1.0 g/cow/d phytonutrients (XT, a mixture of cinnamaldehyde, eugenol, and capsicum), and a combination of YC and XT (YCXT). Cows were fed ad libitum once daily. Treatments were top-dressed at the time of feeding. The basal diet consisted of (dry matter basis): 42.5% corn silage, 12.5% alfalfa haylage, 5.0% grass hay, and 40% concentrates and contained 16.3% crude protein and 32.4% neutral detergent fiber. Dry matter intake was not affected (P = 0.35) by treatment (29.1, 28.2, and 28.6 kg/d for YC, XT, and YCXT, respectively). Milk yield was also similar (P = 0.82) among treatments (42.3, 42.7, and 42.2 kg/d, respectively). Treatment did not affect feed efficiency (average 1.50 kg/kg; SEM = 0.030, P = 0.24) and concentrations of milk fat, true protein, and lactose (average 3.55, 2.98, and 4.84%; respectively; P ≥ 0.20). Concentration of milk urea nitrogen was also similar among treatments. In this experiment, there was no difference in lactational performance between cows supplemented with yeast culture or a blend of phytonutrients. In addition, additive effects of the 2 dietary supplements were not observed.

Key Words: phytonutrient, yeast culture, dairy cow