The effect of high levels of sodium bicarbonate in the drinking water of sheep on rumen function

Abstract

Two groups of rumen fistulated sheep of two each fed on lucerne hay ad lib. (supra maintenance) and teff hay ad lib. (sub-maintenance) respectively, were offered drinking water containing different levels of bicarbonate, viz. 500 (normal tap water), 1000, 2000, 2500, 3000, 4000, 5000 and again 500 ppm. Each level of bicarbonate in the water was given for a four-week period. Feed and water intake was measured daily. Twice a week the pH of the ruminal contents, the ruminal cellulose digestion rate, the ruminal movements and the sugar fermenting ability of the ruminal organisms were determined. The sheep were weighed once a week. The high levels of bicarbonate had no effect on feed and water intake or any of the ruminal functions studied in the well-fed group. The group on poor feed, however, lost their appetites and their ruminal functions were affected. This deterioration was ascribed rather to the poor diet than to the added bicarbonate. Another group of four strong sheep was therefore also given a poor diet (teff hay plus 50 gm of crushed maize per sheep daily) and subjected to the same treatment. Their appetites decreased a little while on the lower levels of bicarbonate in the drinking water, but improved again while on the higher levels. Otherwise the high levels of bicarbonate had no significant effect on the indices estimated.