Influence of hay quality and concentrate level on digesta passage in dairy cows. (Abstract)
- Publication Type
- Contribution to conference
- Authors
- Tafaj, M., V. Kolaneci, A. Maulbetsch, H. Steingaß, W. Drochner
- Year of publication
- 2002
- Published in
- XXII. World Buiatrics Congress
- Page (from - to)
- 193
- Conference name
- World Buiatrics Congress
- Conference location
- Hannover
- Conference date
- 18.-23.08.2002
- Keywords
- dairy cows, digesta, feed components
Objectives: This study aimed to investigate the effects of cell wall content of hay and concentrate level on solid and fluid passage in dairy cows. Methods: Passage was studied in a two factorial experiment with 4 ruminally fistulated cows (BW 500 to 550 kg). Two hay (H) qualities (High: 471 g NDF; Moderate: 619 g NDF/kg DM) were offered with a concentrate (C) mixture (253 g NDF/kg DM) in two H/C-ratios: 50:50 and 78:22. Diets were fed twice a day (08:00 and 20:00) restricted (11.6 to 14 kg DM/d). Solid passage was measured using Yb-NDF. Fibre rich hay particles (size 1.00 to 2.00 mm) were soaked in a 0.35 to 0.40 % w/v aqueous solution of Ytterbium(III)-acetat-tetrahydrate (39 g/1000 g DM residues), rinsed and dried. Fluid passage was measured using LiCo-EDTA (Uden et al. 1980). After a 14 d adaptation period, Yb-NDF (146 g per animal) was fed mixed with 1000 g concentrate before morning feeding. Immediately after ingestion of the Yb-NDF, 15 g liquid marker was administered via rumen fistula into the rumen. 100 to 200 g faecal samples were collected from rectum at 0, 8, 12, 16, 24, 28, 32, 36, 40, 52, 56, 60, 72, 80, 88, 96, 104, 112, 120, 132 and 144h after marker dosage, dried (60 °C) and ground (0 1 mm). The concentrations of Yb and Co were measured using AAS at 398.8 and 240.7 nm. Passage parameters were calculated according to Moore et al. (1992). Results: Increasing the concentrate to hay ratio caused a significant reduction of solid passage rate in rumen only when a fibre poor hay was fed. The solid passage rate in rumen was increased by feeding fibre rich hay with 50 % but not with 20 % concentrate in ration. The difference between fluid and solid Passage rates seemed to be affected primarily by fibre content in hay. Increasing the concentrate level from 20 to 50 % in ration increased the solid to fluid TMRT- ratio significantly (from 1.82 to 2.25). Conclusions: The effects of SC content of hay on passage are dependent on the concentrate level, i.e. SC: NSC