title: Methane production, digestion, ruminal fermentation, nitrogen balance, and milk production of cows fed corn silage- or barley silage-based diets.
abstract: This study evaluated the effects of replacing barley silage (BS) with corn silage (CS) in dairy cow diets on enteric CH4 emissions, ruminal fermentation characteristics, digestion, milk production, and N balance. Nine ruminally cannulated lactating cows were used in a replicated 3 × 3 Latin square design (32-d period) and fed (ad libitum) a total mixed ration (TMR; forage:concentrate ratio 60:40; dry matter basis) with the forage portion consisting of either barley silage (0% CS; 0% CS and 54.4% BS in the TMR), a 50:50 mixture of both silages (27% CS; 27.2% CS and 27.2% BS in the TMR), or corn silage (54% CS; 0% BS and 54.4% CS in the TMR). Increasing the CS proportion (i.e., at the expense of BS) also involved increasing the proportion of corn grain (at the expense of barley grain). Intake and digestibility of dry matter and milk production increased linearly as the proportion of CS increased in the diet. Increasing dietary CS proportion decreased linearly the acetate molar proportion and increased linearly that of propionate. Daily CH4 emissions tended to respond quadratically to increasing proportions of CS in the diet (487, 540, and 523 g/d for 0, 27, and 54% CS, respectively). Methane production adjusted for dry matter or gross energy intake declined as the amount of CS increased in the diet; this effect was more pronounced when cows were fed the 54% CS diet than the 27% CS diet. Increasing the CS proportion in the diet improved N utilization, as reflected by decreases in ruminal ammonia concentration and urinary N excretion and higher use of dietary N for milk protein secretion. Total replacement of BS with CS in dairy cow diets offers a strategy to decrease CH4 energy losses and control N losses without negatively affecting milk performance.
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, Quebec, Canada J1M 0C8. Electronic address: chaouki.benchaar@agr.gc.ca.
authors.forename: C
authors.initials: C
authors.lastname: Benchaar
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, Quebec, Canada J1M 0C8.
authors.forename: F
authors.initials: F
authors.lastname: Hassanat
authors.affiliation: Département des Sciences Animales, Université Laval, Quebec, Quebec, Canada G1V 0A6.
authors.forename: R
authors.initials: R
authors.lastname: Gervais
authors.affiliation: Département des Sciences Animales, Université Laval, Quebec, Quebec, Canada G1V 0A6.
authors.forename: P Y
authors.initials: PY
authors.lastname: Chouinard
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, Quebec, Canada J1M 0C8.
authors.forename: H V
authors.initials: HV
authors.lastname: Petit
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, Quebec, Canada J1M 0C8.
authors.forename: D I
authors.initials: DI
authors.lastname: Massé
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D004063:Digestion / Q000502:physiology*; D005260:Female; D005285:Fermentation; D001467:Hordeum / Q000737:chemistry*; D007774:Lactation / Q000187:drug effects; D008697:Methane / Q000096:biosynthesis*; D008892:Milk / Q000737:chemistry; D009584:Nitrogen / Q000378:metabolism; D012417:Rumen / Q000378:metabolism; D012820:Silage / Q000032:analysis*; D003313:Zea mays / Q000737:chemistry*
chemical_list: D009584:Nitrogen; D008697:Methane
keywords: barley silage; corn silage; dairy cow; enteric methane