title: Long-term effects of feeding monensin on methane production in lactating dairy cows.
abstract: The objective of this study was to determine the long-term effects of feeding monensin on methane (CH4) production in lactating dairy cows. Twenty-four lactating Holstein dairy cows (1.46 +/- 0.17 parity; 620 +/- 5.9 kg of live weight; 92.5 +/- 2.62 d in milk) housed in a tie-stall facility were used in the study. The study was conducted as paired comparisons in a completely randomized design with repeated measurements in a color-coded, double-blind experiment. The cows were paired by parity and days in milk and allocated to 1 of 2 treatments: 1) the regular milking cow total mixed ration (TMR) with a forage-to-concentrate ratio of 60:40 (control TMR; placebo premix) vs. a medicated TMR (monensin TMR; regular TMR + 24 mg of Rumensin Premix/kg of dry matter) fed ad libitum. The animals were fed and milked twice daily (feeding at 0830 and 1300 h; milking at 0500 and 1500 h) and CH4 production was measured prior to introducing the treatments and monthly thereafter for 6 mo using an open-circuit indirect calorimetry system. Monensin reduced CH4 production by 7% (expressed as grams per day) and by 9% (expressed as grams per kilogram of body weight), which were sustained for 6 mo (mean, 458.7 vs. 428.7 +/- 7.75 g/d and 0.738 vs. 0.675 +/- 0.0141, control vs. monensin, respectively). Monensin reduced milk fat percentage by 9% (3.90 vs. 3.53 +/- 0.098%, control vs. monensin, respectively) and reduced milk protein by 4% (3.37 vs. 3.23 +/- 0.031%, control vs. monensin, respectively). Monensin did not affect the dry matter intake or milk yield of the cows. These results suggest that medicating a 60:40 forage-to-concentrate TMR with 24 mg of Rumensin Premix/kg of dry matter is a viable strategy for reducing CH4 production in lactating Holstein dairy cows.
authors: Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1. nodongo@uoguelph.ca
authors: N E
authors: NE
authors: Odongo
authors: R
authors: R
authors: Bagg
authors: G
authors: G
authors: Vessie
authors: P
authors: P
authors: Dick
authors: M M
authors: MM
authors: Or-Rashid
authors: S E
authors: SE
authors: Hook
authors: J T
authors: JT
authors: Gray
authors: E
authors: E
authors: Kebreab
authors: J
authors: J
authors: France
authors: B W
authors: BW
authors: McBride
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D003612:Dairying; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D007476:Ionophores / Q000008:administration & dosage / Q000494:pharmacology*; D007774:Lactation / Q000187:drug effects; D008697:Methane / Q000032:analysis / Q000096:biosynthesis*; D008892:Milk / Q000737:chemistry / Q000187:drug effects; D008894:Milk Proteins / Q000032:analysis / Q000187:drug effects; D008985:Monensin / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D007476:Ionophores; D008894:Milk Proteins; D008985:Monensin; D008697:Methane