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Effects of Asparagopsis taxiformis and oregano leaves on methane emission, rumen fermentation, and lactational performance of dairy cows.

H. A. Stefenoni

Events

06-24-2020

Abstract:

407
Effects of Asparagopsis taxiformis and oregano leaves on methane emission, rumen fermentation, and lactational performance of dairy cows.
H. A. Stefenoni*1, S. E. R�is�nen1, S. F. Welchez1, D. E. Wasson1, C. F. Lage1, A. Melgar1, M. E. Fetter1, M. Hennessy2, B. Vecchiarelli2, J. Bender2, D. Pitta2, C. Yarish3, A. N. Hristov1. 1The Pennsylvania State University University Park, PA, 2University of Pennsylvania Kennett Square, PA, 3University of Connecticut Storrs, CT.

The objective of this experiment was to determine the effect of Asparagopsis taxiformis (AT) and oregano leaves (ORE) on enteric methane (CH4) emission, rumen fermentation, and lactational performance of dairy cows. Twenty Holstein cows (�SD) [95 � 22.0 d in milk and 42 � 2.6 kg milk yield (MY)] were used in a replicated 4 � 4 Latin square design with 4, 28-d periods. Treatments were a basal diet (CON) and CON supplemented with 0.25% AT (LAT), 0.50% AT (HAT), or 2.0% ORE of dry matter intake (DMI). Enteric gas emissions were measured using the GreenFeed system and rumen samples were collected by the ororuminal technique. Data were analyzed using PROC MIXED of SAS with treatment and period in the model. Square and cow within square were random effects. Compared with CON, HAT decreased (P < 0.001) average daily CH4 emission and CH4 yield by 65% (380 and 131 g/d) and 55% (14.0 and 6.32 g/kg DMI), respectively, in experimental periods (P)1 and 2, but had no effect in P3 and P4. The differential response to HAT in P3 and 4 could be attributed to a decrease in bromoform concentration in AT over time (about 74% decrease in 5 mo of storage) observed in a separate experiment. ORE and LAT had no effect on CH4 emission. Compared with CON, HAT decreased (P ≤ 0.006) DMI, MY, and energy-corrected MY by 6.9, 5.7, and 7.3%, respectively. Milk fat and true protein concentrations were not affected by treatment, but lactose was decreased (P < 0.001) by HAT, compared with CON. Total VFA concentration and acetate:propionate ratio tended (P = 0.06) to be lowest for HAT. HAT and ORE increased (P = 0.02) the molar proportion of propionate compared with CON and LAT. Both AT treatments had greater concentrations of butyrate (P < 0.001) compared with ORE and CON. In this experiment, AT fed at 0.5% of DMI decreased CH4 emission by ≥55% in P1 and P2 of the experiment but the effect disappeared by P3 and P4, most likely due to a decrease in bromoform concentration. HAT also decreased DMI and milk production. ORE had no effect on CH4 emission and lactational performance of the cows.

Keywords: methane, Asparagopsis taxiformis, dairy cows.