Language: English/Spanish
References: 15
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ABSTRACT

Changes in the buffering capacity of two diets differing in neutral detergent fi ber level(NDF, 27% and 37%) were evaluated during in vitro digestion as well as for rumination time induced by each diet. Buffer-ing capacity (meq HCl/g of DM/pH) was measured in complete diets and in the in vitro digestion residues after 3, 6, 9, 12, 24 and 48 hours. Rumination time was evaluated in six Holstein heifers (300 ± 17 kg BW). The diet containing 37% NDF had a higher (P ‹ 0.05) buffering capacity (204 meq HCl/g of DM/pH) than the diet containing 27% NDF (147 meq HCl/g of DM/pH) before incubation and after three (699 vs. 458) and six (639 vs. 416) hours of incubation. Rumination time was longer (P ‹ 0.05) in heifers fed with the diet containing 37% NDF (210 min/12 h) than with the diet containing 27% NDF (161 min/12 h). Dietary NDF level has two effects on buffering capacity; its intrinsic buffering properties during the fi rst hours of digestion and an indirect effect by stimulating rumination.

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