Effect of the supplementation with concentrate on the in situ rumen degradability of forage from star grass (Cynodon nlemfuensis) in buffalo calves (Bubalus bubalis)

Four male buffalo calves of the Bufalipso breed (Bubalus bubalis) with 175 +/- 5 kg of liveweight were used and fitted with cannula in rumen. They were distributed according to Latin square design 4 x 4 to assess the effect of different levels of supplementation on the intake and in situ rumen degradability of DM from forage of star grass (Cynodon nlemfuensis). The levels of concentrate in the diet were of 0 (control), 3, 6, and 9 g kg LW-1 and they were provided once in a daytime. The rumen pH did not show differences between treatments. The average values ranged from 6.83 to 6.99. The kinetics of forage DM degradation in rumen showed the highest values (P < 0.05), with 9 g kg LW-1 of concentrate, followed by 6,3 and 0 g kg LW-1 of concentrate (55.22, 54.59, 52 and 48.91%, respectively). The supplementation had effect on the increase of the degradation rate (0.017, 0.023, 0.027 and 0.030 fraction h(-1)), on the decline of the mean time of DM degradability (40.76, 30.13, 25.6 and 23.1 h), and on the increase of the effective degradability in rumen (26.09, 28.46, 29.87 and 30.82% (k = 0.044)) for 0, 3, 6 and 9 g kg LW-1, respectively. The forage DM intake (kg animal d(-1)) did not show differences between treatments, whereas the supplementation increased (P < 0.01) the total DM intake (kg animal d(-1)) per treatments, with values of 470, 1170, and 1370 g for 3, 6, and 9 g kg LW-1, respectively. The results proved the positive effect of the supplementation with different concentrate levels on the optimum pH values in rumen cellulolysis, the improvement of rumen DM degradability, and total DM intake in buffalo calves. This could contribute to the increase in the productive activity of buffalo calves in our rearing conditions.