Estimation of indigestible NDF by in situ procedure in sheep: number of bags and fabric type

This study aimed to evaluate the effects of fabric type (F57 vs. non-woven textile [NWT]) and the number of bags incubated simultaneously in sheep on the determination of indigestible neutral detergent fiber (iNDF). Six fistulated sheep with an initial body weight of 46 ± 3 kg were used in the experiment, which followed a 6 × 6 Latin square design. The study consisted of six periods of 14 days each, allowing for a total incubation time of 336 hours. Two fabric types were used to incubate samples: F57 (Ankom, Fairport, NY) and NWT. Three sample types were analyzed to estimate and compare iNDF content: sorghum silage, ground corn, and sheep feces. For each sample type, bags of the two fabric types were incubated in sets of 4, 8, or 12 bags, totaling 12, 24, or 36 bags per animal per period, respectively. This resulted in a total of 144 bags incubated in situ per period. At the end of each incubation period, the bags were removed from the rumen, washed, oven-dried, and analyzed for NDF content. The results showed no significant differences (P > 0.05) in iNDF estimates between fabric types or across the different numbers of bags incubated. These findings indicate that both F57 and NWT fabrics are suitable for estimating iNDF in feed and feces samples from sheep. Moreover, using up to 36 bags did not compromise the results after 336 hours of incubation. However, further investigation is needed to determine whether incubating more than 36 bags could affect NDF degradation due to bag fill effects.