title: Prediction of enteric methane emissions from Holstein dairy cows fed various forage sources.
abstract: Milk fatty acid (FA) profile has been previously used as a predictor of enteric CH4 output in dairy cows fed diets supplemented with plant oils, which can potentially impact ruminal fermentation. The objective of this study was to investigate the relationships between milk FA and enteric CH4 emissions in lactating dairy cows fed different types of forages in the context of commonly fed diets. A total of 81 observations from three separate 3×3 Latin square design (32-day periods) experiments including a total of 27 lactating cows (96±27 days in milk; mean±SD) were used. Dietary forages were included at 60% of ration dry matter and were as follows: (1) 100% corn silage, (2) 100% alfalfa silage, (3) 100% barley silage, (4) 100% timothy silage, (5) 50:50 mix of corn and alfalfa silages, (6) 50:50 mix of barley and corn silages and (7) 50:50 mix of timothy and alfalfa silages. Enteric CH4 output was measured using respiration chambers during 3 consecutive days. Milk was sampled during the last 7 days of each period and analyzed for components and FA profile. Test variables included dry matter intake (DMI; kg/day), NDF (%), ether extract (%), milk yield (kg/day), milk components (%) and individual milk FA (% of total FA). Candidate multivariate models were obtained using the Least Absolute Shrinkage and Selection Operator and Least-Angle Regression methods based on the Schwarz Bayesian Criterion. Data were then fitted into a random regression using the MIXED procedure including the random effects of cow, period and study. A positive correlation was observed between CH4 and DMI (r=0.59, P0.19). Milk FA profile and DMI can be used to predict CH4 emissions in dairy cows across a wide range of dietary forage sources.
authors.affiliation: 1Département des sciences animales,Université Laval,2425 rue de l'Agriculture,Québec,QC,Canada,G1V 0A6.
authors.forename: D E
authors.initials: DE
authors.lastname: Rico
authors.affiliation: 1Département des sciences animales,Université Laval,2425 rue de l'Agriculture,Québec,QC,Canada,G1V 0A6.
authors.forename: P Y
authors.initials: PY
authors.lastname: Chouinard
authors.affiliation: 2Agriculture and Agri-Food Canada,Dairy and Swine Research and Development Centre,2000 College Street,Sherbrooke,QC,Canada,J1M 0C8.
authors.forename: F
authors.initials: F
authors.lastname: Hassanat
authors.affiliation: 2Agriculture and Agri-Food Canada,Dairy and Swine Research and Development Centre,2000 College Street,Sherbrooke,QC,Canada,J1M 0C8.
authors.forename: C
authors.initials: C
authors.lastname: Benchaar
authors.affiliation: 1Département des sciences animales,Université Laval,2425 rue de l'Agriculture,Québec,QC,Canada,G1V 0A6.
authors.forename: R
authors.initials: R
authors.lastname: Gervais
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D002417:Cattle / Q000378:metabolism*; D004032:Diet / Q000145:classification / Q000662:veterinary*; D019587:Dietary Supplements; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D005285:Fermentation; D001467:Hordeum; D007413:Intestinal Mucosa / Q000378:metabolism*; D007774:Lactation; D000455:Medicago sativa; D008697:Methane / Q000378:metabolism*; D008892:Milk / Q000737:chemistry; D015999:Multivariate Analysis; D031784:Phleum; D012417:Rumen / Q000378:metabolism*; D012820:Silage / Q000032:analysis; D003313:Zea mays
chemical_list: D005227:Fatty Acids; D008697:Methane
keywords: dairy cow; fatty acid; forage; methane emission