Journal article
The definition of acidosis in dairy herds predominantly fed on pasture and concentrates
Journal of Dairy Science, Vol.91(1), pp.308-321
2008
Abstract
This cross-sectional survey examined the prevalence of ruminal acidosis and the effects of acidosis on the production of dairy cattle. Eight fresh cows, 3 primiparous and 5 multiparous (<100 d in milk), were selected randomly from each of 100 dairy herds in 5 regions of Australia. Rumen fluid was obtained from each cow by rumenocentesis and a stomach tube, and samples were tested for pH. Stomach tube rumen fluid samples were analyzed for volatile fatty acid, ammonia, and d-lactate concentrations. On the basis of the results of all assays, cows were categorized into 3 distinct categories (categories 1, 2, and 3) by cluster analysis. The percentages of cattle in categories 1, 2, and 3 were 10.2, 29.9, and 59.9%, respectively. Mean rumen pH for categories 1, 2, and 3 were 5.74±0.47, 6.18±0.44, and 6.33±0.43, respectively. Biochemically, categories 1, 2, and 3 were characterized, respectively, as follows: mean total VFA concentration (mM), 100.74±23.22, 94.79±18.13, and 62.81±15.65; mean ammonia concentration (mM), 2.46±2.02, 7.79±3.75, and 3.64±2.03; and mean d-lactate concentration (mM), 0.34±0.86, 0.28±0.97, and 0.12±0.51. Category 1 cows had higher propionate, valerate, isovalerate, and caproate concentrations and were of lower parity than cows in other categories. Cows in category 1 had higher milk production but lower milk fat content than category 2 cows. Herds were assigned to 1 of 3 groups according to the numbers of cows assigned to each category. Herds with ≥3 of the 8 cows in category 1 were classified as acidotic. Herds with ≥3 of the 8 cows in category 2 were classified as having suboptimal rumen function, and herds with ≥3 of the 8 cows in category 3 were classified as normal. Herds that had 3 or more of the 8 cows in category 1 (acidotic herds) had diets with higher energy and nonfiber carbohydrate contents and a lower neutral detergent fiber content than herds with a high prevalence of category 2 or 3 cows. The lack of significance of a herd effect in the statistical models developed suggests that the categories were robust across production systems, in which diets varied from all pasture to total mixed rations. A point prevalence of 10% (95% credible interval, 8 to 12%) of cows with an acidotic profile indicates a high risk for acidosis in the cattle sampled. The higher nonfiber carbohydrate and lower neutral detergent fiber contents of diets for herds with a high prevalence of category 1 cows (acidotic herds) indicates that there may be opportunities to reduce the risk of acidosis by dietary manipulation.
Details
- Title
- The definition of acidosis in dairy herds predominantly fed on pasture and concentrates
- Authors/Creators
- E. Bramley (Author/Creator) - The University of SydneyI.J. Lean (Author/Creator) - The University of SydneyW.J. Fulkerson (Author/Creator) - The University of SydneyM.A. Stevenson (Author/Creator) - Massey UniversityA.R. Rabiee (Author/Creator) - The University of SydneyN.D. Costa (Author/Creator) - Murdoch University
- Publication Details
- Journal of Dairy Science, Vol.91(1), pp.308-321
- Publisher
- American Dairy Science Association
- Identifiers
- 991005540482207891
- Copyright
- 2008 American Dairy Science Association
- Murdoch Affiliation
- School of Environmental Science
- Language
- English
- Resource Type
- Journal article
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Source: InCites
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- Collaboration types
- Domestic collaboration
- International collaboration
- Citation topics
- 3 Agriculture, Environment & Ecology
- 3.51 Dairy & Animal Sciences
- 3.51.84 Ruminant Nutrition
- Web Of Science research areas
- Agriculture, Dairy & Animal Science
- Food Science & Technology
- ESI research areas
- Agricultural Sciences