title: Enteric methane production in lactating dairy cows with continuous feeding of essential oils or rotational feeding of essential oils and lauric acid.
abstract: Rumen microbes can adapt to feed additives, which may make the decrease in enteric CH4production upon feeding an additive a transient response only. This study investigated alternate feeding of 2 CH4mitigating feed additives with a different mode of action on persistency of lowering CH4production compared with feeding a single additive over a period of 10 wk. Four pairs of cows were selected, and within pairs, cows were randomly assigned to either the control (AR-AR) or the alternating (AR-LA) concentrate treatment. The AR concentrate contained a blend of essential oils (Agolin Ruminant, Agolin SA, Bière, Switzerland; 0.17 g/kg of dry matter) and the LA concentrate contained lauric acid (C12:0; 65 g/kg of dry matter). A basal concentrate without Agolin Ruminant and lauric acid was fed during the pretreatment period (2 wk). Thereafter, the cows assigned to the AR-AR treatment received the AR concentrate during all 10 treatment weeks (5 periods of 2 wk each), whereas cows assigned to the AR-LA treatment received AR and LA concentrates rotated on a weekly basis. Methane emission was measured in climate respiration chambers during periods 1, 3, and 5. From period 3 onward, dry matter intake and milk protein concentration were reduced with the AR-LA treatment. Milk fat concentration was not affected, but the proportion of C12:0 in milk fat increased upon feeding C12:0. Molar proportions of acetate and propionate in rumen fluid were lower and higher, respectively, with the AR-LA than with the AR-AR treatment. Methane yield (g/kg of dry matter intake) and intensity (g/kg of fat- and protein-corrected milk yield) were not affected by treatment. Methane yield and intensity were significantly lower (12 and 11%, respectively) in period 1 compared with the pretreatment period, but no significant difference relative to pretreatment period was observed in period 3 (numerically 9 and 7% lower, respectively) and in period 5 (numerically 8 and 4% lower, respectively). Results indicate a transient decrease in CH4yield and intensity in time, but no improvement in extent or persistency of the decline in CH4due to rotational feeding of essential oils and C12:0 in lactating dairy cows.
authors.affiliation: Animal Nutrition Group, Wageningen Livestock Research, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Klop
authors.affiliation: Animal Nutrition Group, Wageningen Livestock Research, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, the Netherlands. Electronic address: jan.dijkstra@wur.nl.
authors.forename: J
authors.initials: J
authors.lastname: Dijkstra
authors.affiliation: Animal Nutrition Group, Wageningen Livestock Research, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Dieho
authors.affiliation: Animal Nutrition Group, Wageningen Livestock Research, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
authors.forename: W H
authors.initials: WH
authors.lastname: Hendriks
authors.affiliation: Animal Nutrition, Wageningen Livestock Research, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Bannink
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle; D004032:Diet / Q000662:veterinary; D005260:Female; D007774:Lactation; D007850:Lauric Acids; D008697:Methane / Q000096:biosynthesis; D008892:Milk / Q000378:metabolism; D009822:Oils, Volatile / Q000378:metabolism*; D012417:Rumen / Q000378:metabolism
chemical_list: D007850:Lauric Acids; D009822:Oils, Volatile; D008697:Methane
keywords: dairy cow; essential oils; lauric acid; methane