MANIPULATION OF RUMINAL FERMENTATION .2. EFFECT OF SODIUM SULFITE ON BOVINE DIGESTION AND RUMINAL FERMENTATION

In previous work, sodium sulfite was used to manipulate the ruminal fermentation by decreasing the molar per cent acetate and increasing that of propionate and butyrate in lactating cows. In this study the effects of sodium sulfite on ruminal fermentation were studied further, along with its effect on ration digestibility. No effect of sodium sulfite on the digestibility of a high-grain ration fed to steers was observed. However, feed intake on the sulfite diets was variable. In studies with incubated ruminal ingesta, acetate production decreased, whereas the more highly reduced acids were generally increased. Gas production by ruminal ingesta from a cow on a hay diet and another cow on a hay-grain diet was measured with and without sodium sulfite added to the ingesta. Methane production was decreased (P < 0.01) on both types of ingesta by the addition of sulfite. The ratio of carbon dioxide to methane was widened (P < 0.05) from 1.98 with the control hay ingesta to 4.49 with the hay ingesta with 75 mg of sodium sulfite added per 100 ml of ingesta. The ratio of carbon dioxide to methane was widened (P < 0.05) from 2.55 with control hay-grain ingesta to 5.75 with the hay-grain ingesta with 100 mg of Na2SO3 added per 100 ml of ingesta. © 1969, American Dairy Science Association. All rights reserved.