Effect of sodium sulfate concentration in drinking water for beef heifers, and the in vitro effect of bismuth subsalicylate on H2S production and fibre disappearance

This study evaluated the effects of 1) increasing the concentration of sulfate in drinking water on dry matter intake (DMI), water intake, ruminal fermentation, and apparent total-tract digestibility; and 2) water sulfate concentration and bismuth subsalicylate (BSS) dose on in vitro ruminal fermentation. Eight ruminally cannulated beef heifers (382 ± 45 kg) were used in a replicated incomplete 3 × 3 Latin square design. Water treatments contained 342 ± 29 (LS), 2,785 ± 72 (MS), or 4,948 ± 163 mg/L (HS) sulfate. Ruminal digesta was collected to evaluate water sulfate and BSS dose (0.0, 0.2, 0.4, and 0.6% dry matter) on ruminal H2S production in vitro. Water intake increased linearly as water sulfate concentration increased (P = 0.002) but DMI was not affected. Heifers drinking MS and HS had greater ruminal H2S at 10.5 h after water provision than LS (sulfate × time, P < 0.001). In vitro H2S production (µg and µg/mL of rumen inoculum) increased and plateaued with increasing sulfate (P < 0.001) and was linearly reduced (P < 0.001) by increasing BSS dose. Increasing water sulfate concentrations did not negatively affect water or feed intake but increased ruminal H2S concentrations. Bismuth subsalicylate may reduce H2S production.