THE ADDITION OF BUFFERS TO RUMINANT RATIONS: III. THE EFFECT OF ADDITIONS OF SODIUM BICARBONATE, SODIUM PROPIONATE, LIMESTONE AND COD LIVER OIL ON APPARENT DIGESTIBILITY AND NITROGEN RETENTION OF AN ALL-CONCENTRATE RATION

Abstract

Rumen-fistulated yearling steers were used in two 4 × 4 latin square design experiments to determine the digestibility and nitrogen retention of all-concentrate rations with various supplements. The inclusion of 5.7 per cent sodium bicarbonate in either a ground- or dry-rolled-grain ration resulted in an increase in urine excretion. Digestibility of organic matter and nitrogen or nitrogen retention were not affected. The addition of 60 milliliters of cod liver oil (1200 I.U. vitamin A, 150 I.U. vitamin D per gram) per day to the bicarbonate supplemented, ground-grain ration tended to decrease organic matter digestibility while the addition of 3.6 per cent sodium propionate tended to increase organic matter digestibility. Differences between these rations and the bicarbonate ration were not statistically significant; however, the percentage of nitrogen retained on the cod liver oil supplemented ration was significantly (P < 0.05) lower than on the propionate supplemented ration.The inclusion of 5.7 per cent ground limestone significantly (P < 0.05) reduced the digestibility of dry matter, and nitrogen, but the digestibility of organic matter was not significantly lower at this probability level.