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Effects of enzyme extracts from Aspergillus oryzae and Aspergillus niger on lactational performance of dairy cows fed a decreased-energy diet.

M. E. Fetter

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06-23-2020

Abstract:

280
Effects of enzyme extracts from Aspergillus oryzae and Aspergillus niger on lactational performance of dairy cows fed a decreased-energy diet.
M. E. Fetter*1, S. E. R�is�nen1, C. de Assis Lage1, H. A. Stefenoni1, A. Melgar1, S. F. Cueva1, D. E. Wasson1, D. M. Paulus Compart2, A. N. Hristov1. 1Department of Animal Science, The Pennsylvania State University University Park, PA, 2PMI Arden Hills, MN.

The objective of this study was to investigate the effects of enzyme extracts from Aspergillus oryzae and Aspergillus niger (ENZ) on lactational performance and blood metabolites of Holstein cows fed a diet in which corn grain (8.6% of dry matter; PCON diet) was replaced with wheat straw (NCON and ENZ diets). Following a 2-wk covariate period, 48 multi- and primiparous cows averaging (�SD) 151 � 45 d in milk (DIM) and 593 � 55.7 kg BW were blocked based on DIM, milk yield (MY) and parity and randomly assigned to 1 of 3 treatments in an 8-wk randomized complete block design experiment: (1) positive control diet (PCON; 0.6 Mcal/d NEL balance, based on NRC, 2001), (2) negative control (NCON; −1.4 Mcal/d NEL balance) and (3) NCON supplemented with ENZ at 113 g/d per cow (−1.3 Mcal/d NEL balance). Data were analyzed using PROC MIXED of SAS with block and block � treatment as random effects. Compared with PCON (24.0 kg/d), dry matter intake (DMI) decreased (P = 0.03) in both NCON and ENZ diets (22.5 and 22.1 kg/d, respectively). MY was also decreased (P < 0.001) by NCON and ENZ (32.0, and 30.8 kg/d, respectively) compared with PCON (35.4 kg/d). Milk fat concentration, but not yield, was greater (P = 0.001) for NCON and ENZ, compared with PCON (4.14, 4.08, and 3.76%, respectively). Compared with PCON, milk lactose concentration and yield and true protein yield were decreased (P < 0.001) by NCON and ENZ and so was energy-corrected milk yield (ECM; P = 0.01). Feed efficiency and ECM feed efficiency were not affected (P ≥ 0.51) by diet. Cows gained less (P = 0.01) BW and blood glucose concentration tended to be lower (P = 0.06) for NCON and ENZ compared with PCON. The ENZ diet had no effect on milk yield and composition, feed efficiency, BW change, and blood metabolites compared with NCON. In this experiment, replacing corn grain with straw decreased DMI, MY, and milk true protein and lactose concentrations but increased milk fat concentration and did not affect feed efficiency in dairy cows. The enzyme extracts had no effect on the lactational performance of the cows.

Keywords: starch, fiber, dairy cow.