Discrepancies between milk fat content, chewing activity and rumen milieu concerning structural effectiveness evaluation of diets with different hay: concentrate ration in dairy cows
- Publication Type
- Contribution to conference
- Authors
- Tafaj, M., Maulbetsch, A., Zebeli, Q., Steingaß, H. and Drochner, W.
- Year of publication
- 2005
- Published in
- Berichte der Gesellschaft für Ernährungspyhsiologie
- Editor
- H. Martens (Hrsg.)
- Pubisher
- DLG-Verlags-GmbH , Frankfurt/M
- Series/labeling
- Proc. Soc. Nutr. Physiol.
- Page (from - to)
- 128
- Conference location
- Stuttgart-Hohenheim
- Conference date
- 08.-10.03.2005
- Keywords
- dairy cow, feeding, milk fat, rumen milieu
Introduction and objectives: Structural effectiveness of diets becomes more important in feeding of high-yielding dairy cows and is strongly affected by the foragexoncentrate ratio of the diet. Currently Systems of evaluation of structural effectiveness are mainly based on milk fat content and chewing activity, while rumen milieu is not sufficiently considered. Often, there are observed discrepancies conceming the minimum dietary fibre level related to milk fat content, chewing activity and healthy rumen function. The objective of this study was to demonstrate exemplary these discrepancies for hay-based diets with different hay : concentrate ratios in mid-lactation dairy cows. Methods: Four ruminally cannulated Holstein cows (BW 615kg, 103 day in milk and 29 kg milk/d at Start of experiment) were fed long hay (26.8% CF) combined with a concentrate mixture (35% maize, 20% wheat, 18% barley, 23% soybean meal) in 5 levels (DM basis): 70, 6t), 50, 40 and 25% which correspond to 8.0, 10.9, 13.5, 16.1 and 20.1% hay crude fibre (SCF), respectively. Concentrate was offered in 3 to 5 meals/d and the intake level was fixed at 18kg DM/d. Milk fat content, chewing activity, ruminal fermentation patterns (in fluid and solid digesta, every 3 h) and digesta particle size distribution (every 6 h) were measured. The regression of SCF to milk fat content, chewing activity and ruminal parameters were tested by SAS. The Mixed procedure with Estimate Option (intercept=l) was used to estimate SCF levels which corresponded to the target values of parameters studied.