Effects of gamma irradiation on ruminal DM and NDF degradation kinetics of alfalfa hay.

The effects of gamma irradiation on ruminal dry matter, Neutral Detergent Fiber (NDF) degradation of alfalfa hay were investigated. Alfalfa hay samples were irradiated by gamma irradiator at doses of 50, 100 and 150 kGy under identical conditions of temperature and humidity. Nylon bags of untreated or irradiated samples were suspended in the rumen of three Taleshi bulls for up to 96 h and resulting data were fitted to non-linear degradation model to calculate degradation parameters. Results indicated that the washout fractions of dry matter and NDF increased linearly (p < 0.001) with increasing irradiation dose. The b fraction and the degradation rate of the b fraction (c) of DM and NDF were the highest at 50 kGy dose. Effective degradability of DM and NDF increased linearly with increasing irradiation dose. Gamma irradiation at doses of 50, 100 and 150 kGy increased the effective NDF degradability of alfalfa hay at rumen outflow rate of 0.05 h(-1) by about 8, 11 and 12%, respectively. Gamma irradiation affects on the hydrogenic bonds and with theirs breakdowning causes the wander-valls power weaken, that results in the degradation of cellulose and increasing of DM and NDF degradability.