EVALUATION OF FOUR SORGHUM GENOTYPES USING THE SEMI AUTOMATED IN VITRO GAS PRODUCTION

The objective of this study was to evaluate the ruminal fermentationkinetics and in vitro dry matter degradability of four genotypes of sorghum(ATF53*9929036, ATF54*9929036, CMSXS217*9929012 e VOLUMAX) using thesemi-automated gas production technique. Incubation times adopted were 6, 12, 24, 48,72 and 96 h, and the frequency of gas production collections were: 2, 4, 6, 8, 10, 12, 15,18, 21, 24, 30, 36, 48, 60, 72 and 96 h. The coefficient of determination resulting fromcumulative gas production data (r2 = 0.99) and dry matter degradability showed that thegas produced represents the substrates fermentability. The VOLUMAX genotype showed ahigher rate of fermentation (μ) (0.043 (mL/g DM/h), with lower lag phase (L) (1 h e 16 min). The other genotypes showed μ values from 0.038 to 0.034 mL/g DM/h, and L from 1 h50 to 1 h e 72. These results indicated that VOLUMAX genotype is better for silageproduction.