EFFECTS OF HEMIACETAL OF CHLORAL AND STARCH ON THE PERFORMANCE OF BEEF STEERS 1,2

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1 EFFECTS OF HEMIACETAL OF CHLORAL AND STARCH ON THE PERFORMANCE OF BEEF STEERS 1,2 N. A. Cole s and J. E. McCroskey 4 Oklahoma Agricultural Experiment Station, Stillzoater SUMMARY Two metabolism trials and one feedlot trial were conducted to determine the effect of Hemiacetal of chloral and starch (HCS) on methane production, energy utilization and feedlot performance of steers fed an 80% concentrate ration. Twelve steers were used in the two metabolism trials to determine the effect of HCS (.30% of ration) on methane production, and energy utilization by beef steers after 30 and 120 days on feed. In the feedlot trial, the influence of HCS at a constant level (.2%) (CHCS) and at an increasing level (.1,.2 and.3%) (IHCS) in the ration on feedlot performance was investigated using 27 beef steers. At 30 days on feed, steers fed HCS had lower (P<.05) energy digestibilities (DE) and metabolizable energy (ME) values and tended to have lower net energy (NEro+g) and energy retentions (ER) despite a significant reduction in methane production. After 120 days on feed, the HCS steers had apparendy adapted to the high level of HCS. DE, NEm+g and ER values were similar for both groups at 120 days on feed although the HCS ration tended to have higher ME values. In the feedlot, average daily gains (ADG) were 1.40, 1.35 and 1.10 kg for the control, CHCS and IHCS groups, respectively. When compared to controls, the CHCS ration had a 6% improvement in feed efficiency but a 9% decrease in feed intake. (Key Words: Energy Utilization, Methane Inhibitors, Beef Cattle.) Journal article 2962 of the Agricultural Experiment Station, Oklahoma State University, Stillwater. This research was conducted by the Department of Animal Sciences and Industry in cooperation with the U.S.D.A., Agricultural Research Service, Southern Region. 2 The authors wish to express their appreciation to Smith Kline Animal Health Products for providing the methane inhibitor. 3Present address: Department of Animal Industries, University Idaho, Moscow Present address: Department of Animal Science, Texas Technological University, Lubbock INTRODUCTION Production of methane due to microbial fermentation in the forestomach of ruminants may account for as much as 6 to 10% of the gross energy intake of the animal (Blaxter and Clapperton, 1965). Whereas many metabolites produced in microbial fermentation (VFA, NH3) are available to the animal or the rumen microbial population for energy or protein synthesis, most methane is lost by eructation (Dougherty et al., 1965). Recently, studies have indicated that an animal's performance can be improved by inhibition of methane production with compounds added to the ration (Trei and Scott, 1971a, b). Hemiacetal of chloral and starch (HCS) has been shown to be a potent methane inhibitor that is easily added to ruminant rations (Trei et al., 1972). However, an adjustment period appears to be required to obtain feed intakes equal to control animals. It was suggested that a gradual increase in the level of HCS in the ration may maximize the improvement in performance noted with inhibition of methane production (Trei et al., 1971). Most of the work with this compound has been with moderately high roughage rations and only limited data are available on the effects of HCS on performance of beef steers fed high concentrate rations. This paper reports the effects of HCS on the performance of beef steers fed a sorghum grain (sorghum, grain variety, sorghum vulgare, grain, Ref. No ) 80% concentrate ration. EXPERIMENTAL PROCEDURE Metabolism Trials. In two metabolism trials, 12 steers of Hereford and Angus breeding averaging 262 kg (range 225 to 315 kg) were paired according to shrunk weight and randomly allotted to one of two 80% concentrate rations. Ration 1 was the control, while ration 2 was the same as ration 1 plus.3% HCS (table 1) JOURNAL OF ANIMAL SCIENCE, Vol. 41, No. 6, 1975

2 1736 COLE AND McCROSKEY TABLE 1. INGREDIENT COMPOSITION OF CONTROL RATIONS Metabolism Feedlot Ingredient I RN a trials trial Percent of ration b Sorghum, grain variety, grain dry rolled (4) Alfalfa, aerial pt, dehy grnd, mn 15 prot, (1) Cotton, seed hulls (1) Soybean, seed, solv-extd, grnd mx 7 fbr (5) Sugarcane molasses, dehy (4) Trace mineralized salt Calcium chloride Aureomycin-50 c Calcium phosphate dibasic, comm (6) Calcium carbonate CaCO 3 commercial mn 38% Ca (6) Ammonium chloride alnternational reference number. bon an air-dry basis. CAdded to supply 22 mg chlortetracycline per kilogram ration. American Cyanamid Company, Princeton, New Jersey. The first metabolism trial (trial 1) was conducted when the animals had been on the respective treatments approximately 30 days. All steers were fed the control ration individually twice daily for 3 weeks prior to the start of the trial and were placed in digestion stalls at least 3 weeks prior to the start of fecal and urine collection. Each trial consisted of a 7-day fecal and urine collection period followed by two consecutive 24-hr gas collection periods in open circuit indirect respiration chambers. Excreta were collected daily, weighed and 10% aliquots stored at 4 C. Fecal aliquots were composited and two sub-samples taken, one of which was stored fresh at -4 C and the second dried in a forced air oven at 60 C, ground, then stored at 4 C. Acidified daily urine aliquots were composited and a 200 ml subsample was stored at -4 C. Feed intakes throughout the digestion trial were maintained at a level of 90% of maximum intake attained during the preliminary period in the digestion stalls. Feed samples were taken daily and composited for future analysis. Methane and carbon dioxide were determined with infrared analyzers and gas volume was measured by dry gas meters with simultaneous measurements of pressure, temperature and humidity to permit correction to standard conditions. Oxygen was measured by a paramagnetic analyzer. Heat production was calculated using the equation of Brouwer (1965). The equation used was: HP = (3.866 X 02) + (1.2 x CO2) -- (.518 x CH4)-- (1.431 X N) where HP is heat production is Kcal per day, 02 is liters of oxygen consumed per day, CO2 and CH4 are liters of carbon dioxide and methane produced per day, and N is grams of urinary nitrogen excreted per day. Feedlot Trial. In an 84-day finishing trial, 27 crossbred steers averaging 316 kg (range 290 to 335 kg) were randomly allotted to pens with three pens per treatment. The treatments were: Ration 1-control (table 1), Ration 2-control +.2% HCS fed a constant level (CHCS) and Ration 3-control + HCS fed at increasing dose levels (IHCS). In ration 3 HCS was fed at levels of.1,.2 and.3%, increases being made at 28-day intervals. NH4C1 was added to all rations to prevent urinary calculi. All steers were adapted to the control ration for 2 weeks prior to the start of the trial. The cattle were kept on concrete slatted floors and were allowed to eat ad libitum from bulk self-feeders. Initial and final weights were taken after a

3 HCS AND ENERGY UTILIZATION 1737 TABLE 2. AVERAGE STEER WEIGHTS AND FEED INTAKEs FOR METABOLISM TRIALS Trial 1 Trial 2 Item Control HCS a SE c Control HCS a SE c Weight (kg) MBS b (kg) DM Intake (kg) GE (Meal/day) GE (kcai/kg MBS) bmetabolic body size = weight kg -75. CStandard error of the mean. 14-hr shrink without feed and water. Feed intakes were measured by pen at 28-day intervals. Feed samples were taken weekly, for laboratory analysis as feed was added to the self feeders. Air dried feed and fecal samples were analyzed for dry matter (A.O.A.C., 1960) and heat of combustion using a Parr adiabatic bomb calorimeter. Urine samples were dried on powdered cellulose at 40 C in a vacuum oven for gross energy determination. Kjeldahl nitrogen (A.O.A.C., 1960) was determined on liquid urine and air-dry feed samples. Data for the metabolism trials were analyzed by analysis of variance as a split plot design with treatments as main plots and trials as subplots. Feedlot performance was analyzed by analysis of variance as a completely randomized design with pens as the experimental unit. Simple effects were tested by least significant difference protected by a preliminary F test (Steel and Torrie, 1960). RESULTS AND DISCUSSION Energy Balance Trial 1. Average steer weights and feed intakes are presented in table 2. Steer weights and intakes of dry matter (DM) and gross energy (GE) were similar for both treatment groups. Gaseous energy losses are presented in table 3. Methane losses were lower (P<.05) for the HCS group. Hydrogen production, estimated using the factor of Johnson (1971, 1972), accounted for approximately 1% of the GE intake of the HCS group. A 23% decrease in total gaseous energy losses was obtained by feeding HCS. This was smaller than the 40% decrease estimated using the equations of Johnson (1971, 1972) derived with sheep on a 60% concentrate ration. TABLE 3. GASEOUS ENERGY LOSSES IN ENERGY BALANCE TRIALS Trial 1 Trial 2 Item Control HCS a SE e Control HCS a SE e CH 4 (% GE) b " H 2 (% GE) c ~ Total gas (% GE)b, c CH 4 (% GE) d Total gas (% GE) d bdetermined by respiration calorimetry. CH 2 production = 43% of decreased methane loss (Johnson, 1971, 1972). d.. Determined using mean GE intakes by the equations of Johnson (1971, 1972). estandard error of the mean. * Significantly lower than control in same trial (P<.05).

4 1738 COLE AND McCROSKEY TABLE 4. EFFECT OF HCS ON ENERGETIC EFFICIENCY Trial 1 Trial 2 Item/treatment Control HCS a seb Control HCS a SE b DE (% GE) ME (% GE) " ME (% DE) ME (Mcal/kg DM) * NEm+g (% GE) NEm+ ~ (% ME) NEm+g (Mcal/kg DM) HP (kcal/kg.75)c ER (kcal/kg-75) d bstandard error of the mean. CliP = Heat production. der = Energy retention. *Significantly different from control group in same trial (P<.05) * At 30 days on feed, HCS treatment reduced (P<.05) DE (table 4). Johnson (1972) reported that HCS (2 g HCS/kg ration) increased energy digestibility at maintenance intake but deceased it at 2 x maintenance. The apparent HCS x feeding level interaction (P<.10), however, was not noted when HCS levels were lowered by about 50% and the concentrate level was increased (Johnson, 1974). Singh and Trei (1972) reported slightly higher digestibilities of DM, protein, crude fiber and NFE when sheep were fed HCS in a 50% concentrate ration at 1.3 x maintenance. The lower energy digestibilities obtained on our study suggest that the level of HCS used (.3%) may have been too high and adversely affected the rumen fermentation to the extent that digestion in the lower gut could not compensate for the decrease in ruminal fermentation. Hinman and Johnson (1974) have demonstrated the limited capacity of steers to digest the starch of dry rolled sorghum grain in the lower gut. If an increased amount of dietary starch reached the intestine undegraded a decrease in total energy digestibility could be expected. Although HCS resulted in lowered gaseous energy losses, the lower DE values for the HCS ration resulted in lower (P<.05) values for ME as a percent of GE (ME/GE) and ME per kilogram of ration dry matter and a higher (P<.10) value for ME as a percent of DE (ME/DE). Johnson (1972, 1974) noted a 2.7% and 3.5% increase in ME/GE with HCS treat- ment, whereas a decrease of 2.7% was noted in this trial. Net energy (NEm+gmcal/kg DM) and energy retention (ER) values for the HCS ration tended (P<.10) to be lower than for the control group. The similar values for NE as a percent of ME (NE/ME) suggest that the apparent differences in NEm+g and ER were due to the decreased energy digestibility and not to an effect on the efficiency of utilization of ME. Johnson (1972) also reported that HCS had no apparent effect on the efficiency of utilization of ME. Energy Balance Trial 2. Steer weights, dry matter intakes and GE intakes were similar for both rations in trial 2 (table 2). At 120 days on feed, the HCS ration tended to have lower methane and total gaseous losses than the control ration, but the differences were not statistically significant (table 3). Johnson (1974) noted a significant decrease in HCS effectiveness between 3 and 30 days on trial, whereas, in the present study, HCS effectiveness did not decrease from day 30 to day 120. Total gaseous losses were reduced by 23 and 16%, respectively, by HCS after 30 and 120 days on trial. Johnson (1974) reported a much larger decrease (51 to 12%) in gaseous losses between 3 and 30 days on HCS with lambs. Using the equation of Johnson (1972) derived from short term experiments, a 38% decrease in methane production would be expected with HCS feeding.

5 HCS AND ENERGY UTILIZATION 1739 TABLE 5. FEEDLOT PERFORMANCE OF STEERS Item Control CHCS IHCS SE b ADG (kg) Feed/gain (kg) DM/gain (kg) Feed intake a DM intake a GE intake (Mcal) GE/gain (Mcal/kg) akg/hd/day. bstandard error of the mean. In contrast to trial 1, no significant differences were noted in the digestion of energy (DE/GE) in trial 2 (table 4). Due to slightly lower gaseous losses, ME/GE and ME/DE tended (P<.10) to be higher and ME per kilogram DM consumed was higher (P<.05) for the HCS ration in trial 2. NEm+g, heat production and ER were similar for both treatments. There was a significant increase in ME/GE and ME per kilogram of DM consumed for the HCS ration between trials 1 and 2, due primarily to an increased DE, suggesting an adaptation to the inhibitor. Johnson (1974) noted a significant increase in DE between 3 and 30 days on HCS but no apparent effect on ME due to an increase in gaseous losses. Feedlot Trial. Feedlot performance data are presented in table 5. The IHCS group tended to have lower daily gains than the control and CHCS groups, but the differences were not significant. Weight gains for the control and CHCS groups were similar. Previous studies (Trei and Scott, 1971a; Trei et al., 1971) obtained a slight improvement in daily weight gain when sheep were fed rations containing HCS. The concentrate level in the present study was higher than in previous studies (80% vs 60%) and could be a possible reason for the differences in response to HCS. The CHCS ration had a slight advantage in feed efficiency over the control and IHCS rations (6% and 19%, respectively), but the differences were not statistically significant. Dry matter intakes were similar for the CHCS and IHCS treatment groups with the control group having slightly higher intakes. Previous studies (Trei and Scott, 1971a; Trei et al., 1971, 1972) have noted similar improvements in feed efficiency and similar decreases in feed intakes with HCS feeding. Table 6 shows the average daily feed intakes for each treatment group during each 28-day period. Periods 1, 2 and 3 represent successive 28-day periods on treatment. DM intakes for steers in the IHCS group declined markedly when the HCS level in the ration was increased from.2 to.3% while steers in the control and CHCS treatment groups tended to increase or maintain their average daily DM intakes each period of the trial. The CHCS steers, however, TABLE 6. AVERAGE DALLY FEED INTAKE PER HEAD BY PERIOD:FEEDLOT TRIAL Item Control CHCS IHCS SE a Period 1 Feed intake (kg) DM intake (kg) Period 2 Feed intake (kg) DM intake (kg) Period 3 Feed intake (kg) DM intake (kg) astandard error of the mean.

6 1740 COLE AND McCROSKEY TABLE 7. ENERGETIC EFFICIENCY: COMBINED ENERGY BALANCE TRIALS b Energy fraction Control d Hcsa,d CH * H2 c Heat production ~ ME ~ ME (% DE) * Energy retention NEm+g * NEm+ ~ (Mcal/kg DM) ~ bas a % of GE unless indicated. CEstimated from factors of Johnson (1971, 1972). dmean +- standard error of the mean. *Significantly different from control (P<.05). were unable to adapt to the HCS sufficiently to obtain feed intakes equal to those of the control group. Discussion Results of the energy balance trials suggest that feeding HCS as.3% of a high energy ration would give no apparent improvement in energy utilization of steers and may initially reduce energy utilization. By pooling the results of both trials the energetic efficiency over an extended feeding period can be estimated (table 7). HCS feeding increased (P<~.05) ME/DE but had no apparent effect on energy retention (% GE) or net energy (% GE and Mcal/kg DM). As previously noted by Johnson (1972, 1974), HCS had no effect on the composition of energy gained with fat gain representing approximately 62% and 75% of energy retention in trials 1 and 2, respectively. Feed intakes in the metabolism stalls were relatively low (approximately 1.5% of body weight) in comparison to normal feedlot conditions. This is primarily due to the animals being restrained with little opportunity for activity. This difference in feed intake results in net energy estimates that are approximately 20% higher when determined by respiration calorimetry than when determined by the comparative slaughter technique (Kiesling et al., 1973). Johnson (1972) reported that HCS was more effective in increasing ME (% GE) at 1 x maintenance than at 2 x maintenance when daily HCS intake was held constant. At higher feed intakes, however, methane production was more completely suppressed. Since methane production (% GE) normally declines with higher feed intakes (Blaxter and Clapperton, 1965) and becomes a smaller fraction of energy losses, methane inhibition may be less beneficial at higher feed intakes. In the feedlot trial, feeding HCS at a level of.2% of the ration appeared to slightly improve feed efficiencies and gross energy utilization. Johnson (1974), however, reported that a level of about.1% may be sufficient to promote improved energy retentions in sheep fed high concentrate rations. Sawyer et al. (1974) obtained similar increases in energy retentions of sheep fed the methane inhibitor bromochloromethane (BCM), regardless of the level of BCM fed. At higher feed intakes, however, they noted no improvement in performance. The results of this study appear to indicate no advantage in feeding HCS at the levels used. However numerous factors such as HCS level, feeding level, concentrate level and feeding frequency appear to affect the results of HCS feeding. The influence of other factors which affect rumen fermentation such as type of grain and processing methods may also be important in determining the effect of HCS on energy utilization. Previous studies have generally used a pelleted corn based ration, whereas, a nonpelleted rolled sorghum grain ration was used in this study. This difference in rations could be a possible explanation for the discrepancies noted between this and previous studies with HCS. LITERATURE CITED A.O.A.C Official Methods of Analysis (9th Ed.). Association of Official Agriculture Chemists.

7 HCS AND ENERGY UTILIZATION 1741 Washington, D. C. Blaxter, K. L. and J. L. Clapperton Prediction of the amount of methane produced by ruminants. Brit. J. Nutr. 19:511. Brouwer, E Report of sub-committee on constants and factors. Proc. 3rd Symposium on Energy Metabolism, Troon. EAAP Publ. No. II. Academic Press, New York. Dougherty, R. W., C. H. Mullenax and M. J. Allison Physiology of digestion in the ruminant. R. W. Dougherty, Ed. Butterworths, London. Hinman, D. D. and R. R. Johnson Influence of processing methods on digestion of sorghum starch in high concentrate beef cattle rations. J. Anim. Sci. 39:417. Johnson, D. E Methane inhibition effects on energy balance of sheep. J. Anim. Sci. 33:288 (Abstr.). Johnson, D. E Effects of hemiacetal of chloral and starch on methane production and energy balance of sheep fed a pelleted diet. J. Anim. Sci. 35:1064. Johnson, D. E Adaptational responses in nitrogen and energy balance of lambs fed a methane inhibitor. J. Anita. Sci. 38:154. Kiesling, H. E., J. E. McCroskey and D. G. Wagner A comparison of energetic efficiency of dry rolled and reconstituted rolled sorghum grain by steers using indirect calorimetry and the comparative slaughter technique. J. Anim. Sci. 37:790. Sawyer, M. S., W. H. Hoover and C. J. Sniffen Effects of a ruminal methane inhibitor on growth and energy metabolism in the ovine. J. Anim. Sci. 38:908. Singh, J. K. and J. E. Trei Influence of a methane inhibitor on nutrient digestibilities and nitrogen retention in lambs. J. Anim. Sci. 34:363 (Abstr.). Steel, R. G. D. and J. H. Torrie Principles and procedures of statistics. McGraw-HiU Book Co., N. Y. Trei, J. E., R. C. Parish, Y. K. Singh and G. C. Scott Effect of methane inhibitors on rumen metabolism and feedlot performance of sheep. J. Dairy Sci. 54:536. Trei, J. E. and G. C. Scott. 1971a. Effect of methane inhibitors on feedlot performance of lambs. J. Anim. Sci. 33:301 (Abstr.). Trei, J. E. and G. C. Scott. 1971b. Performance of steers on the methane inhibitor-hcs. J. Anim. Sci. 33:301 (Abstr.). Trei, J. E., G. C. Scott and R. C. Parish Influence of methane inhibition on energetic efficiency of lambs. J. Anim. Sci. 34:510.