title: A comparative study at two different altitudes with two dietary nutrition levels on rumen fermentation and energy metabolism in Chinese Holstein cows.
abstract: The object of this study was to investigate the effect of two altitudes (1600 vs. 3600 m) with two nutritional levels [5.88 MJ/kg dry matter (DM) vs. 7.56 MJ/kg DM] on apparent total tract digestibility, rumen fermentation, energy metabolism, milk yield and milk composition in Chinese Holstein cows. Sixteen Chinese Holstein cows in their third lactation with close body weights, days in milk and milk yield were randomly divided into four groups, of which two were directly transferred from Lanzhou (altitude of 1600 m) to Lhasa (altitude of 3600 m). Four treatments (high plateau and high nutrition level, HA-HN; high plateau and low nutrition level, HA-LN; low plateau and high nutrition level, LA-HN; and low plateau and low nutrition level, LA-LN) were randomly arranged in a 2 × 2 factorial experimental design. Results indicated that the apparent total tract digestibility of a diet's DM, organic matter, crude protein, neutral detergent fibre and acid detergent fibre and DM intake were not affected by either altitude or nutrition level (p > 0.05). Milk protein percentage was higher for the diet with the high level of nutrition than for the diet with low nutrition level irrespective of altitude (p < 0.05). Percentages of milk fat and milk lactose were not affected by either altitude or nutrition level (p > 0.05). The metabolizable energy used for milk energy output was decreased by high altitude in comparison with that at low altitude (p < 0.05). No differences were observed in the live body weight or body condition score (BCS) of Chinese Holstein cows among all of the four treatments (p > 0.05).
authors.affiliation: Lanzhou Institute of Animal & Veterinarian Pharmaceutics Science, Lanzhou, China Institute of Ensilage and Processing of Grass, Nanjing Agricultural University, Nanjing, China Institute of Geographical Science and Resource, Chinese Academy of Sciences, Beijing, China.
authors.forename: G H
authors.initials: GH
authors.lastname: Qiao
authors.affiliation: Lanzhou Institute of Animal & Veterinarian Pharmaceutics Science, Lanzhou, China Institute of Ensilage and Processing of Grass, Nanjing Agricultural University, Nanjing, China Institute of Geographical Science and Resource, Chinese Academy of Sciences, Beijing, China.
authors.forename: T
authors.initials: T
authors.lastname: Shao
authors.affiliation: Lanzhou Institute of Animal & Veterinarian Pharmaceutics Science, Lanzhou, China Institute of Ensilage and Processing of Grass, Nanjing Agricultural University, Nanjing, China Institute of Geographical Science and Resource, Chinese Academy of Sciences, Beijing, China.
authors.forename: C Q
authors.initials: CQ
authors.lastname: Yu
authors.affiliation: Lanzhou Institute of Animal & Veterinarian Pharmaceutics Science, Lanzhou, China Institute of Ensilage and Processing of Grass, Nanjing Agricultural University, Nanjing, China Institute of Geographical Science and Resource, Chinese Academy of Sciences, Beijing, China.
authors.forename: X L
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Lanzhou Institute of Animal & Veterinarian Pharmaceutics Science, Lanzhou, China Institute of Ensilage and Processing of Grass, Nanjing Agricultural University, Nanjing, China Institute of Geographical Science and Resource, Chinese Academy of Sciences, Beijing, China.
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.affiliation: Lanzhou Institute of Animal & Veterinarian Pharmaceutics Science, Lanzhou, China Institute of Ensilage and Processing of Grass, Nanjing Agricultural University, Nanjing, China Institute of Geographical Science and Resource, Chinese Academy of Sciences, Beijing, China.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Zhu
authors.affiliation: Lanzhou Institute of Animal & Veterinarian Pharmaceutics Science, Lanzhou, China Institute of Ensilage and Processing of Grass, Nanjing Agricultural University, Nanjing, China Institute of Geographical Science and Resource, Chinese Academy of Sciences, Beijing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000531:Altitude; D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D002681:China; D004032:Diet / Q000662:veterinary*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005285:Fermentation; D012417:Rumen / Q000502:physiology*