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

This study evaluated the effects of ( i) increasing the concentration of sulfate in drinking water on dry matter intake (DMI), water intake, ruminal fermentation, and apparent total-tract digestibility, and ( ii) 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 low (342 ± 29 mg/L; LS), medium (2785 ± 72 mg/L; MS), or high (4948 ± 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 H 2 S 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 H 2 S at 10.5 h after water provision than LS (sulfate × time, p < 0.001). In vitro H 2 S 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 H 2 S concentrations. Bismuth subsalicylate may reduce H 2 S production.