Palatability in sheep and in vitro nutritional value of dried and ensiled sainfoin (Onobrychis viciifolia) birdsfoot trefoil (Lotus corniculatus), and chicory (Cichorium intybus)

Abstract

Three temperate forages, sainfoin, birdsfoot trefoil, and chicory, characterized by elevated contents of plant secondary compounds, were compared to a ryegrass-clover mixture (control) in dried (Experiment 1) and ensiled form (Experiment 2) in their palatability and nutritional value. Palatability was measured in adult wethers (n = 6) allowed to choose between the familiar control forage and one of the three test plants. Palatability index was calculated from differences in intake of control and test plants measured after given times. Generally at first contact, palatability of the unfamiliar plants was low. Lag time until palatability index approached or exceeded a value of 100 was 2 – 5 d, but could not be related to the content of condensed tannins. Sainfoin had a high palatability, the highest content of condensed tannins (77.4 ± 10.23 g/kg DM), a high content of duodenally utilisable crude protein (94.7 ± 16.87 g/100 g CP), and a high content of metabolizable energy (9.5 ± 0.38 MJ ME/kg DM), making this plant most promising for various purposes including anthelmintic action.

Keywords:

• Condensed tannins
• palatability
• degradability
• protein
• ensiling
• ruminant

Acknowledgements

The authors would like to thank P. Schafer for the construction of the pens used in the animal experiments, A. Perroud for the establishment of the Butanol-HCl method and C. Kunz for the assistance with ammonia analysis in the incubation fluid. A. Scharenberg acknowledges the receipt of financial support from the Swiss Federal Office for Agriculture (FOAG).