In vitro degradation characteristics of timothy and red clover at different harvest times

The nutritional value of red clover (Trifolium pratense L.) and timothy (Phleum pratense L.) were studied over two consecutive growing seasons (1995 and 1996) with an in vitro gas production technique and chemical analysis. The decline in degradability was more pronounced with increasing maturity in timothy than in red clover during spring growth, but similar during summer growth. Red clover contained more components soluble in neutral detergent solution (NDS) at all harvest occasions. The fractional degradation rate for the NDS fraction was lower in red clover compared to timothy. Red clover had slightly higher fractional degradation rate for the whole forage, but the total kinetic release of energy was similar for the two species at the same harvest time. The results indicate that timothy and red clover have different intrinsic characteristics limiting degradation. Effects of the treatments with NDS on the allocation of pectins could partially explain the differences in degradation characteristics.