title: Methane production and digestion of different physical forms of rapeseed as fat supplements in dairy cows.
abstract: The purpose of this experiment was to study the effect of the physical form of rapeseed fat on methane (CH4) mitigation properties, feed digestion, and rumen fermentation. Four lactating ruminal-, duodenal-, and ileal-cannulated Danish Holstein dairy cows (143 d in milk, milk yield of 34.3 kg) were submitted to a 4×4 Latin square design with 4 rations: 1 control with rapeseed meal (low-fat, CON) and 3 fat-supplemented rations with either rapeseed cake (RSC), whole cracked rapeseed (WCR), or rapeseed oil (RSO). Dietary fat concentrations were 3.5 in CON, 5.5 in RSC, 6.2 in WCR, and 6.5% in RSO. The amount of fat-free rapeseed was kept constant for all rations. The forage consisted of corn silage and grass silage and the forage to concentrate ratio was 50:50 on a dry matter basis. Diurnal samples of duodenal and ileal digesta and feces were compiled. The methane production was measured for 4 d in open-circuit respiration chambers. Additional fat reduced the CH4 production per kilogram of dry matter intake and as a proportion of the gross energy intake by 11 and 14%, respectively. Neither the total tract nor the rumen digestibility of organic matter (OM) or neutral detergent fiber were significantly affected by the treatment. Relating the CH4 production to the total-tract digested OM showed a tendency to decrease CH4 per kilogram of digested OM for fat-supplemented rations versus CON. The acetate to propionate ratio was not affected for RSC and WCR but was increased for RSO compared with CON. The rumen ammonia concentration was not affected by the ration. The milk and energy-corrected milk yields were unaffected by the fat supplementation. In conclusion, rapeseed is an appropriate fat source to reduce the enteric CH4 production without affecting neutral detergent fiber digestion or milk production. The physical form of fat did not influence the CH4-reducing effect of rapeseed fat. However, differences in the volatile fatty acid pattern indicate that different mechanisms may be involved.
authors: Department of Animal Science, and.
authors: M
authors: M
authors: Brask
authors: Department of Animal Science, and. Electronic address: Peter.Lund@agrsci.dk.
authors: P
authors: P
authors: Lund
authors: Department of Animal Science, and.
authors: M R
authors: MR
authors: Weisbjerg
authors: Department of Animal Science, and.
authors: A L F
authors: ALF
authors: Hellwing
authors: Department of Animal Science, and.
authors: M
authors: M
authors: Poulsen
authors: Department of Food Science, Aarhus University, AU Foulum, PO Box 50, DK 8830 Tjele, Denmark.
authors: M K
authors: MK
authors: Larsen
authors: Department of Animal Science, and.
authors: T
authors: T
authors: Hvelplund
mesh_terms: D000641:Ammonia / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D029741:Brassica rapa / Q000378:metabolism*; D002417:Cattle / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage*; D004043:Dietary Fiber / Q000378:metabolism; D019587:Dietary Supplements; D004063:Digestion; D005232:Fatty Acids, Volatile / Q000032:analysis; D005243:Feces / Q000737:chemistry; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007774:Lactation; D008697:Methane / Q000032:analysis / Q000096:biosynthesis*; D006109:Poaceae; D012417:Rumen / Q000378:metabolism; D012639:Seeds; D012820:Silage; D003313:Zea mays
chemical_list: D004041:Dietary Fats; D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D000641:Ammonia; D008697:Methane