EFFECT OF SODIUM BICARBONATE IN THE DRINKING WATER OF RUMINANTS ON THE DIGESTIBILITY OF A PELLETED COMPLETE RATION 1

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1 EFFECT OF SODIUM BICARBONATE IN THE DRINKING WATER OF RUMINANTS ON THE DIGESTIBILITY OF A PELLETED COMPLETE RATION 1 ORK reported recently indicates that W concentrated or pelleted complete rations which are high in cereal grains can be successfully fed to ruminants (Lassiter et al., 1960, 1962; Wise et al., 1961; Cullison and Ward, 1961). Cullison et al. (1960) observed poor rumination and lowered rumen ph in fattening steers fed pelleted complete rations. Sodium bicarbonate incorporated in the drinking water of steer calves fed these pellets increased their feed intake and gains over those of calves fed the pellets without sodium bicarbonate (Cullison and Ward, 1961). Whether the increased gains were due to the increased feed intakes or to better nutrient utilization was not studied. Failure to ruminate may prevent the recirculation of the mineral cations of the saliva and thus the buffering of the volatile fatty acids found in the rumen (Matrone et al., 1959). Incorporation of sodium bicarbonate in the drinking water under these conditions might serve to buffer the acids normally buffered by the mineral cations from the saliva and thereby affect digestibility. This study was conducted to determine the effect of sodium bicarbonate incorporation in the drinking water on the digestibility in steers and lambs of the nutrients in a pelleted complete ration. Experimental Three digestion experiments were conducted. The same pelleted complete ration was fed in all experiments and contained, in percent; corn, 50; cottonseed meal, 10; molasses, 9; ground Coastal hay, 30; and ground limestone, defluorinated phosphate and salt, 0.33 each. Six half-sib yearling Angus steers, weigh- z Journal Paper No. 266 of the College Experiment Station of the University o.f Georgia College of Agriculture Experiment Stations. z Present address: Area Livestock Specialist, Cooperative Extension Service, Camilla, Georgia. a We are grateful to J. L. Cartoon for the statistical analyses and to Merck and Company, Rahway, New Jersey for supplying the sodium bicarbonate. J. W. LASSITER AND ~[. K. COOK 2, 3 University o] Georgia, Athens 384 ing from lb., were randomly allotted to two groups (1 and 2) and these groups were randomly allotted to the treatments in both experiments 1 and 2. Each experiment consisted of a double reversal experimental design with three comparison periods and two treatments. Each comparison period included a preliminary period of 14 days followed by a total collection period of 7 days. Treatment 1 consisted of the pelleted ration and untreated drinking water while treatment 2 was composed of the same ration and 0.5% USP grade sodium bicarbonate incorporated in the drinking water. In experiment 1, full feeding was employed to determine whether the primary effect of sodium bicarbonate was on feed intake and whether, under these conditions, there was a measurable effect on digestibility. In experiment 2, treatments were the same as in experiment 1 except that twice daily equalized feeding was employed, basing the intake on the steer eating the least at the start of the experiment. The steers received all the water they would accept immediately after each feeding. Experiments 1 and 2 were conducted in a metabolism room maintained at 72 ~ F. during February-March and April- June, respectively. The steers were fed the rations in an unpaved paddock for a 14-day adjustment period preceding the beginning of experiment 1. Between experiments 1 and 2, the steers again were allowed the freedom of the unpaved paddock for 10 days. In experiment 3, 6 wether lambs, weighing from lb., were employed in a double reversal experimental design with three comparison periods and two treatments. The experiment was conducted during July and August in the same room as experiments 1 and 2. In each comparison, a preliminary period of 10 days preceded a total collection period of 7 days. Treatments were the same as in experiment 2 except that water was offered ad libitum and 425 gm. of the pelleted ration were fed twice daily to each lamb. In all experiments fecal excretions were

2 SODIUM BICARBONATE IN WATER OF RUMINANTS 385 TABLE 1. MEAN APPARENT DIGESTION COEFFICIENTS IN EXPERIMENTS, 1 AND 2 Comparison Group Dry Ether Crude Nitrogenperiod number matter extract fiber free extract Nitrogen Energy 1 1 a ~ " ~ ~ ~ '~ , a NaHCOa in water. collected daily, weighed, m~xed thoroughly and an aliquot placed in a plastic bag, sprinkled with a 5% solution of H2SO4, and frozen at --17 ~ C. At the end of each collection period, the samples were thawed, dried in a forced air oven at 40 ~ C. for 80 hours, allowed to equilibrate with the air, weighed and ground in a Wiley mill through a 40-mesh screen. Representative sub-samples were obtained from the ground composite samples for proximate analysis by the methods of the A.O.A.C. (1950) except that total nitrogen was determined instead of protein nitrogen. Energy was determined in an adiabatic Parr Bomb Calorimeter. The data were subjected to statistical analysis with methods given by Lucas (1956). Results and Discussion In table 1 the mean apparent digestion coefficients are listed for each item studied in experiments 1 and 2. Average daily feed, water, and sodium bicarbonate intakes during the collection periods are shown in table 2. Mean squares for digestion coefficients and TABLE 2. AVERAGE DAILY FEED, WATER, AND NaHCOa INTAKES DURING COLLECTION PERIODS FOR EXPERIMENTS 1 AND 2 Steer number Comparison period Feed, kg ~ 4.02 ~ 3.96 ~ H~O, kg. 17, NaHCO3, gin Feed, kg a 4.09 ~ 2170 ~ H20, kg NaHCO~, gm Feed, kg. 3:~ a 3;~ 9 4:~ H~O, kg. 17, NaHCOs, gin Feed, kg a 2.54 ~ 2.54 a H20, kg NaHCOs, gm Feed, kg ~ 2.54 ~ 2.54 ~ H20, kg NaHCOs, gm Feed, kg [ 54 ~ 2.54 ~ 2.54 ~ tt20, kg I NaHCO3, gm NaHC08 in water.

3 386 LASSITER AND COOK TABLE 3. ANALYSES OF VARIANCE OF DIGESTIBILITIES AND FEED AND WATER INTAKE IN EXPERIMENTS 1 AND 2 Mean squares Source of Dry Ether Crude Nitrogenvariation d.f. matter extract fiber ~ree extract Nitrogen Energy Feed Water Treatment , ~ Error , , , Treatment , Error , , * P <.05. feed and water intakes are shown in table 3. There were no statistically significant differences in digestibility due to sodium bicarbonate in either experiment. This agrees with the work of Nicholson et al. (1962) who included 5.7% sodium bicarbonate in either a ground or dry-rolled grain ration for rumen-fistulated yearling steers and reported an increase in urine excretion, but no effect on the digestibility of organic matter or nitrogen. Preston et al. (1962), however, reported significant increases in dry matter intake and digestibility with increasing levels of sodium bicarbonate when they included 2.5% and 7.5% sodium bicarbonate in all-concentrate diets for earlyweaned calves. Lassister et al. (1961) used the same ration and sodium bicarbonate level in the water that was used in the present study and found tureen anaerobic populations and volatile fatty acid concentrations 4 hours after feeding to be influenced by sodium bicarbonate. This could have occurred, however, without affecting the digestibility. Emery and Brown (1961) added 1 lb. per day of sodium or potassium bicarbonate to the rations of dairy cows fed grain to appetite and reported an increase in the ph of the rumen contents, a prevention of the decline in milk fat percent frequently associated with such rations, but no appreciable alteration of the molar proportions of the rumen acids. The type of ration fed may affect the response to sodium bicarbonate. The pelleted complete ration used in the present study had a crude fiber content of 11.26%. The increase in digestibility from sodium bicarbonate found by Preston, however, occurred on a standard early weaning mixture for calves and no response to sodium bicarbonate was obtained on a diet containing 10% grass meal. Growth responses from sodium bicarbonate reported in some of the growth trials, have been with rations practically devoid of roughage, even that from barley or oat hulls (Wise et al., 1961; Lassiter et al., 1962). In experiment 1 of the present study there was no significant effect on feed intake, but there was a significant (P~.05) difference in water intake. In experiment 2 the difference for ether extract approached significance even though there was only 3.7% ether extract in the ration. Sodium soaps excreted in the feces would not be determined as ether extract, however, and unless these were determined as total lipids, the apparent digestibility would tend to be a high figure. Also, some of the fecal fat might not be of dietary origin and this would affect the digestion coefficient for ether extract. Measurement of water intake in our study was complicated by some unavoidable wastage of water by the steers. Average water intakes were greater for the steers receiving sodium bicarbonate in experiment 2, but the differences were not statistically significant. In experiment 3 (table 4) there was an TABLE 4. MEAN APPARENT DIGESTION COEFFICIENTS IN EXPERIMENT 3 Comparison Dry Ether Crude period Group matter extract * fiber * NFE Nitrogen Energy 1 1" , , ~ ~ i a 0.5% sodium bicarbonate in the drinking water. * Significantly (P~.05) affected by treatment.

4 SODIUM BICARBONATE IN WATER OF RUMINANTS 387 increase in the digstibility of the ether extract and crude fiber (P(.05) in lambs due to sodium bicarbonate. This differs from the results with steers in experiment 1 and 2 and from the results of Rhodes and Woods (1960) who reported no difference in the digestibility of high concentrate rations fed to lambs due to sodium bicarbonate fortification. However, in the study by Rhodes and Woods, the sodium bicarbonate was incorporated into the feed rather than the drinking water. Where offered in the feed, particularly with high levels, the level of sodium bicarbonate may be a factor in the acceptability of the feed, and thereby affect the digestibility. Denton and Sabine (1961) and Beilharz and Kay (1961) have studied factors that affect the sodium appetite of sheep. Their results indicate this to be a promising field of study. In experiment 3 the lambs in group 2 which had sodium bicarbonate incorporated only in period 2 consistently had greater digestion coefficients for all nutrients during the per~d that sodium bicarbonate was being received. TABLE 5. AVERAGE DAILY WATER (KG.) AND NaHCO~ (GM.) INTAKES DURING COLLEC- TION PERIODS OF EXPERIMENT 3 Lamb number Comparison period S 6 1 a , I First l~ne, water consumption; second line, NaHCO~ c~>nsumption. This was not true with all nutrients for group 1 which received sodium bicarbonate in periods 1 and 3. Average water consumption was higher with lambs receiving sodium bicarbonate (table 5), but it was quite variable and at least part of this variation was due to an inability to prevent lambs from wasting some of their water. For this reason little confidence is placed in the figures on water consumption. An effect of sodium bicarbonate on the digestibility of ether extract and crude fiber in lambs but not in steers may have been caused by the ad libitum rather than twice daily offering of water. It is possible, however, that there may be a species difference in this regard. Summary Six yearling Angus steers were employed in two digestion experiments and six wether lambs in a third to study the effects in ruminants of incorporating sodium bicarbonate in their drinking water on the digestibility of dry matter, ether extract, crude fiber, NFE, protein or energy in a pelleted complete ra- 9 tion. Each experiment consisted of a double reversal experimental design with three comparison periods and two treatments. Treatment 1 consisted of the pelleted ration and untreated drinking water. Treatment 2 was composed of the same ration with 0.5% sodium bicarbonate in the drinking water. In experiment 1, with steers, twice daily full feeding and watering were employed, whereas, in experiment 2, twice daily equalized feeding and twice daily watering were utilized. There were no statistically significant differences in digestibility due to sodium bicarbonate in either experiment. In experiment 1 there was a significant difference in water intake, but not in feed intake, due to sodium bicarbonate. In experiment 3, with lambs, twice daily equalized feeding with ad lib#urn watering resulted in a significant increase in the digestibility of the ether extract and crude fiber due to sodium bicarbonate incorporation. Literature Cited A.O.A.C Official Methods of Analysis (Tth ed.). Association of Official Agricultural Chemists, Washington, D. C. Beilharz, S. and R. N. B. Kay Factors affecting the sodium appetite of sheep. ~[. Physiol. 155:60P. Cullison, A. E., B. M. Campbell and R. W. Walker Effect of physical form of the ration on steer performance and certain rumen phenomena. J. Animal Sci. 19:1256. Cullison, A. E. and C. S. Ward Effect of sodium bicarbonate, sodium acetate and strychnine sulfate on the performance of beef animals receiving a pelleted ration. J. Animal Sci. 20:930. Denton, D. A. and J. R. Sabine The selective appetite for Na shown by Na-deficient sheep. I. Physiol. 157:97. Emery, R. S. and L. D. Brown Effect of feeding sodium and potassium bicarbonate on milk fat, rumen pit and volatile fatty acid production. J. Dairy Sci. 44:1899. Lassiter, J. W., Prasob Buranamanas and M. K. Hamdy Effect of sodium bicarbonate on rumen microbial activity. J. Animal Sci. 20:940. Lassiter, J. W., A. E. Cullison and E. P. Warren Effect of sodium bicarbonate on growth and nutrient digestibility in lambs. J. Animal Sci. 21:385. Lassiter, ~[. W., J. W. White, M. K. Cook, E. P. Warren and R. A. Long Feed efficieneies of young ruminants fed low-roughage rations. J. Animal Sci. 19:1272.

5 388 LASSITER AND COOK Lucas, H. L Switchback trials for more than two treatments. J. Dairy Sci. 39:146. Matrone, G., H. A. Ramsey and G. H. Wise Role of sodium and potassium cations in volatile fatty acid metabolism of ruminants. Proc Cornell Nutr. Conf. for Feed Manuf. p. 36. Nicholson, J. W. G., H. M. Cunningham and D. W. Friend The addition of buffers to ruminant rations. II Additional observations on weight gains, efficiency of gains and consumption by steers on all-concentrate rations. Can. J. Animal Sci. 42:75. Preston, T. R., F. G. Whitelaw, W. A. MacLeod and Euphemia B. Charleson The effect of sodium bicarbonate in all-concentrate diets for earlyweaned calves. An. Prod. 4:299. Rhodes, R. W. and Walter Woods Nutrient additions and physical factors that influence lamb performance on high concentrate pelleted rations. J. Animal Sci. 19:1289. Wise, M. B., T. N. Blumer, G. Matrone and E. R. Barrick Investigations on the feeding of allconcentrate rations to beef cattle. J. Animal Sci. 20:561.