Effect of hay particle size and concentrate level on ruminal mat characteristics in dairy cows.
- Publication Type
- Contribution to conference
- Authors
- Zebeli, Q., Tafaj, M., Junck, B. and Drochner, W.
- Year of publication
- 2005
- Published in
- Berichte der Gesellschaft für Ernährungsphysiologie
- Editor
- H. Martens
- Pubisher
- DLG-Verlags-GmbH , Frankfurt/M
- Series/labeling
- Proc. Soc. Nutr. Physiol.
- Page (from - to)
- 140
- Conference location
- Stuttgart-Hohenheim
- Conference date
- 08.-10.03.2005
- Keywords
- concentrate level, dairy cow, hay diet, particle size
Objective; Digesta stratification is the most important pre-condition for an optimal rumen digestion. The objective of this research was to investigate the effect of particle size of hay (H) and concentrate level (C) on ruminal mat characteristics at different times after the morning feeding. Methods: Four ruminally cannulated (0=100 mm) late-lactating Holstein cows (BW 684 ± 6.3kg) were assigned in a 4x4 Latin Square design to each of four diets differing in mean particle size [PL: long (L=30mm) and fine (F=6mm)] of hay (54.7% NDF) and the level (C: 20% and 60%, DM basis) of a wheat-barley-based concentrate mixture. Feed intake was fixed at 17 kg DM/d. Hay and concentrate were offered in 2 and 4 daily portions, respectively. After a 1 ld adaptation period, the ruminal mat consistency was measured over 2 days lh prior to, and 3, 9 and 13h after the moming feeding according to Welch (1982), where a 800-g weight (0=40 mm) was placed direct on the ventral rumen floor 30 min prior to measurement to ensure normal mat reförrnation. Upon release of an exterior 3200-g weight, the ascension rate (mm/sec) of the 800-g weight (ArW) through the ruminal digesta was recorded to characterize the ruminal mat consistency. In addition, solid digesta samples were collected in dorsal and ventral rumen layer (D) according to Tafaj et al. (2004) and NDF content was determined. A portion of digesta was frozen (-20°C) for further wet-sieving analysis. The rumen digesta was manually emptied lh before morning feeding and the digestamass of the rumen (DMR) was measured. Effects of H, G, D and their interactions and relationshipsxwere tested by PROC MIXED and PROC REG (SAS, 8.2), respectively.