The intake and digestion of fresh and dried Digitaria decumbens grass by rams was compared using
a 2×2 factorial design. The experiment took place in Guadeloupe (French West Indies) in 1996. Eight
rams (mean liveweight: 45·7±3·1 kg) were maintained in metabolism cages. Digitaria decumbens
grass was cut daily and distributed to four of them, the other four were fed the following day with
the equivalent forage which had meanwhile been dried for 20 h at 60°C. Chemical composition (g/kg
of dry matter (DM)) of the two diets based on neutral detergent fibre (NDF, 713, S.E. 18), acid
detergent fibre (ADF, 361, S.E. 13) and crude protein (CP, 90, S.E. 4) was similar. The DM intake (61·0
and 53·2 g/W0·75, S.E. 2·0, P<0·05), the NDF (0·753 and 0·727,
S.E. 0·004, P<0·011) and CP (0·588
and 0·544, S.E. 0·014, P<0·09) total tract digestibility of fresh and dried herbage were different.
Nylon bag estimates of effective DM degradability and fractional degradation rates (per h) in the
rumen were 0·436, 0·414 (S.E. 0·005, P<0·004) and 0·048, 0·038 (S.E. 0·002, P<0·02) for fresh and
dried grass, respectively. Rumen digestibility of organic matter and NDF were 0·516, 0·541 (S.E. 0·021)
and 0·763, 0·692 (S.E. 0·019), respectively. The rumen turnover rates of particles (per h) were 0·024 and
0·015 (S.E. 0·001, P<0·05) for fresh and dried forage respectively. The efficiency of microbial protein
synthesis (g microbial nitrogen/kg organic matter apparently degraded in the rumen) was similar with
the two diets : 33·5 and 33·0 (S.E. 3·3, P<0·9) for fresh and dried forage respectively. In conclusion,
fresh Digitaria decumbens was nutritionally superior to dried. This is probably due to a faster
degradation rate and a lower rumen retention time of the fresh forage.
