J. Anim. Sci. 2004. 82:2193-2199
© 2004 American Society of Animal Science
Rice mill feed as a replacement for broiler litter in diets for growing beef cattle
W. N. Stacey1 and
D. L. Rankins, Jr.2
Department of Animal Sciences, Auburn University, AL 36849
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Abstract
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The efficacy of replacing broiler litter with rice mill feed was evaluated in four experiments. In Exp. 1, 40 predominantly Angus steers (initial BW = 277 ± 18.2 kg) were fed four dietary treatments for 112 d (five steers per pen; two pens per diet). Dietary treatments (DM basis) were as follows: 1) 47% broiler litter:53% corn; 2) 60% rice mill feed:40% corn; 3) 50% rice mill feed:50% corn; and 4) 40% rice mill feed:60% corn. All diets, along with bermudagrass hay, were fed free choice. Daily gains were faster (P < 0.10) for the 50:50 and 40:60 diets (1.26 and 1.30 kg/d, respectively) than for the broiler litter diet (0.89 kg/d). Daily DMI was less (P < 0.10) by steers consuming rice mill feed-based diets than by those consuming broiler litter-based diets. In Exp. 2, 16 Angus x Charolais steers (initial BW = 277 ± 22.7 kg) were fed the same four diets used in Exp. 1 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was not different (P > 0.10) among diets. Nutrient digestibilities did not differ among diets (P > 0.10). In Exp. 3, 40 Continental cross steers (initial BW = 257 ± 21.3 kg) were fed one of four dietary treatments for 112 d (five steers per pen; two pens per diet). On a DM basis, diets were as follows: 1) 47% broiler litter:53% soyhulls; 2) 70% rice mill feed:30% soyhulls; 3) 60% rice mill feed:40% soyhulls; and 4) 50% rice mill feed:50% soyhulls. All diets, along with bermudagrass hay, were fed free choice. Daily gains were less (P < 0.05) for the broiler litter diet than for the 60:40 and 50:50 diets (1.05, 1.16, and 1.28 kg/d, respectively), and steers fed the broiler litter diet consumed less DM than did steers fed the varying rice mill feed-based diets (P < 0.10). In Exp. 4, 16 Angus x Charolais steers (initial BW = 292 ± 21.1 kg) were fed the same four diets as in Exp. 3 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was less (P < 0.01) for the broiler litter diet (5.0 kg/d) than for the 70:30, 60:40, and 50:50 diets (7.8, 7.9, and 7.9 kg/d, respectively). Digestibilities for DM, OM, and ADF did not differ (P > 0.10) among treatments; however, CP digestibility was greatest (P < 0.10) for the 60:40 diet, and NDF digestibility was least (P < 0.10) for the 70:30 diet. Rice mill feed can be used to replace broiler litter to formulate low-cost diets for stocker calves. Soyhulls and corn can be blended with rice mill feed to produce acceptable backgrounding diets for growing beef calves.
Key Words: Beef Cattle • Broiler Litter • Rice Mill Feed
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Introduction
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Broiler litter, also referred to as recycled poultry bedding, has been used successfully in stocker cattle diets as an economical alternative feed (Rankins et al., 2002
); however, the continued use of animal wastes as feedstuffs is uncertain. Another economical feed readily available in the southeastern United States is rice mill feed, which is a combination of rice hulls and rice bran, usually in the same proportion that it is in when milled from rice grain: 66% hulls and 34% bran (White and Hembry, 1985). Limited information is available on the feeding value of rice mill feed. White and Habetz (1969) indicated that 5% rice mill feed could be included into a finishing diet for beef cattle with no negative effects. Brazle and Coffey (1990) reported daily gains of 0.4 kg/d for heifers fed 66% rice mill feed and 33% alfalfa pellets for 60 d.
Extensive research has been conducted on both rice hulls and rice bran as alternative feedstuffs. Rice hulls have been shown to be less digestible than grass hay (bermudagrass and sudangrass) when included as a roughage source at concentrations above 15% of the diet (White 1966; White and Hembry, 1982). In addition, rice hulls can cause digestive problems, and in some cases, even cause death as a result of rumen compaction (Noland and Gainer, 1953). However, grinding rice hulls made them more palatable and eliminated any digestive disturbances when they were fed to gestating-lactating ewes (Noland and Gainer, 1953). Of the rice by-products, rice bran contains the most nutrients (approximately 13% CP and 15% fat) and has been used effectively in cattle diets (White and Davis, 1962).
The objective of this research was to evaluate the use of rice mill feed as a replacement for broiler litter in backgrounding diets for beef cattle.
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Materials and Methods
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Two feeding trials were conducted at the Wiregrass Research and Extension Center in Headland, AL, and two digestibility studies were conducted at the E. V. Smith Beef Research Unit in Tallassee, AL. All experimental procedures were reviewed and approved by the Auburn University Institutional Animal Care and Use Committee. Table 1 shows the nutrient composition of the broiler litter and rice mill feed ingredients that were used. Broiler litter was obtained from a house that had grown 6 batches of birds on peanut hull bedding. Upon arrival at the research facility, litter was deep-stacked and covered with 0.006-inch-thick (6-mil) polyethylene sheeting as described by Rankins et al. (1993).
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Table 1. Nutrient composition of broiler litter and rice mill feed used to formulate the diets fed to beef cattle
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Feeding and Digestibility Trials
Experiment 1.
Forty steers of predominantly Angus breeding (initial average BW = 277 ± 18.2 kg) were assigned randomly to one of four dietary treatments and fed for a 112-d period (five steers per pen; two pens per diet). Pens were 0.2-ha drylots containing a covered feedbunk 3.1 m in length. On a DM basis, dietary treatments were as follows: 1) 47% broiler litter:53% corn; 2) 60% rice mill feed:40% corn; 3) 50% rice mill feed:50% corn; and 4) 40% rice mill feed:60% corn. Diets were provided ad libitum, and steers had continuous access to bermudagrass hay. Feed bunks were always replenished in such a manner that bunks were never empty; feed was usually added twice per week. All diets contained lasalocid at a concentration of 18 to 20 mg/kg to provide 150 to 200 mg of lasalocid per animal daily. Diets with varying concentrations of rice mill feed contained 0.5% dicalcium phosphate and 0.5% trace mineral salt to meet NRC (1996) requirements for Ca and P. Steers were weighed initially and then on 28-d intervals throughout the 112-d trial. Weights were taken on d 28, 56, and 84 to ensure that no animals were performing poorly and that none of the dietary treatments resulted in weight loss. Unshrunk animal weights were taken between 0700 and 1030. Feed and hay intakes were monitored by recording amount fed and then at completion amount remaining was subtracted for total intake determination.
Experiment 2.
Sixteen Angus x Charolais steers (initial average BW = 277 ± 22.7 kg) were assigned randomly and fed the same four dietary treatments including 0.5% of BW/d as bermudagrass hay in a digestibility study while housed in individual metabolism stalls for 10 d. The steers were fed the four diets for 30 d before being housed in the metabolism stalls. During the collection period, feed intake, feed refusals, and fecal output were collected, weighed, and sampled (10%) daily. Samples were dried at 55°C to a constant DM and stored for further laboratory analysis.
Experiment 3.
Forty Continental-cross steers (initial average BW = 257 ± 21.3 kg) were assigned randomly to one of four dietary treatments and fed for a 112-d period (five steers per pen; two pens per diet). Pens were 0.2 ha drylots containing a covered feedbunk 3.1 m in length. On a DM basis, dietary treatments were as follows: 1) 47% broiler litter:53% soyhulls; 2) 70% rice mill feed:30% soyhulls; 3) 60% rice mill feed:40% soyhulls; and 4) 50% rice mill feed:50% soyhulls. Diets were provided ad libitum, and steers had continuous access to bermudagrass hay. Feed bunks always were replenished in such a manner that bunks were never empty; feed was usually added twice per week. As in Exp. 1, diets contained lasalocid at a concentration of 18 to 20 mg/kg in order to provide 150 to 200 mg of lasalocid per animal daily. Diets with varying concentrations of rice mill feed contained 0.5% dicalcium phosphate and 0.5% trace mineral salt to meet NRC (1996) requirements for Ca and P. Steers were weighed initially and then on 28-d intervals throughout the 112-d trial. As in Exp. 1, animal weights (unshurnk) were taken between 0700 and 1030 on d 28, 56, and 84 to ensure that the dietary treatments did not result in weight loss. Feed and hay intakes were monitored as in Exp. 1.
Experiment 4.
Sixteen Angus x Charolais steers (initial average BW = 292 ± 21.1 kg) were each assigned randomly to receive one of the same four dietary treatments used in Exp. 3 plus 0.5% of BW bermudagrass hay while housed in individual metabolism stalls for a 10-d period. The same procedures that were described in Exp. 2 were used in this experiment.
Chemical Analysis
All samples were ground to pass a 2-mm screen in a Wiley mill. Chemical analyses were performed on each sample in duplicate. All samples were analyzed for DM, CP, and ash (AOAC, 1995), as well as NDF and ADF by the method described by Goering and Van Soest (1970), which was adapted to the Ankom 200/220 fiber analyzer (Fairport, NY). Gross energy was determined by isoperibol bomb calorimetry (Parr Instrument Co., Moline, IL).
Statistical Analysis
Data were subjected to analysis of variance using GLM procedures of SAS (SAS Inst. Inc., Cary, NC). Data were analyzed as a completely randomized design, using pen as the experimental unit in Exp. 1 and 3 and animal as the experimental unit in Exp. 2 and 4. Because the main objective of this research was to evaluate the use of varying combinations of rice mill feed relative to broiler litter, treatments were compared using Dunnett’s procedure (Steel and Torrie, 1980), whereby each of the diets containing rice mill feed was compared with the diet containing broiler litter. Any differences of P < 0.10 were deemed significant and were differentiated from P < 0.05 by different superscripts.
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Results
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Experiment 1
There were no differences in initial BW; however, final BW was greater for steers consuming mixtures containing 50 and 40% rice mill feed than for steers consuming the broiler litter mixture (P < 0.10; Table 2). Daily gains were greater (P < 0.10) for steers consuming diets containing 50 and 40% rice mill feed than for steers consuming the broiler litter diet. Steers consuming the mixture containing 60% rice mill feed had gains similar (P > 0.10) to those consuming broiler litter. Daily DMI was reduced for calves consuming rice mill feed compared with those consuming the broiler litter diet (P < 0.10). No differences were observed for consumption of the feed mixtures (P > 0.10) but hay intake was lower for steers consuming diets containing rice mill feed (P < 0.05). Average daily gains were greatest, whereas total DMI was least, in animals fed the mixtures containing rice mill feed. This is reflected in G:F, which was increased in animals consuming diets containing rice mill feed (P < 0.05).
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Table 2. Daily gain and dry matter intake by steers fed varying levels of broiler litter, rice mill, feed, and corn (Exp. 1)
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Experiment 2
Nutrient composition of feed mixtures and hay fed during the digestibility study in Exp. 2 are shown in Table 3. Nutrient composition values are reported on a DM basis. Dry matter intake and apparent nutrient digestibilities in beef cattle are shown in Table 4. No differences for DMI or apparent digestibilities were detected (P > 0.10).
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Table 4. Effects of replacing broiler litter with rice mill feed on apparent nutrient digestibilities in beef cattle (Exp. 2)
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Experiment 3
No differences were found for initial BW (P > 0.10; Table 5). Final BW for steers fed the broiler litter diet were lower than for steers fed the 50% rice mill feed diet (P < 0.05). Final BW of steers consuming the 60 and 70% rice mill feed diets were not different from those consuming broiler litter. Similarly, ADG by steers fed the broiler litter mixture were lower than by steers fed the 60 and 50% rice mill feed mixtures (P < 0.10) and not different from those fed 70% rice mill feed (P > 0.10). Total DMI did not differ among diets (P > 0.10); however, the proportion of total DMI that was hay vs. feed mixture differed (P < 0.10). Steers fed the broiler litter diet consumed less than steers fed the varying rice mill feed mixtures (P < 0.10). Hay intake of steers fed the broiler litter diet was greater than that of steers fed the varying rice mill feed diets (P < 0.05).
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Table 5. Daily gain and DMI for steers fed varying levels of broiler litter, rice mill feed, and soyhulls (Exp. 3)
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Experiment 4
Nutrient composition of diets and hay fed to steers during the digestibility study in Exp. 4 are shown in Table 6. Values are reported on a DM basis. Dry matter intake and apparent nutrient digestibilities in beef cattle are shown in Table 7. Dry matter intake for steers fed diets containing rice mill feed was greater than for steers fed the broiler litter diet (P < 0.01). Digestibility of the NDF fraction was less for the 70% rice mill feed diet than for the diet containing broiler litter (P < 0.10). Crude protein digestibility was greater (P < 0.10) for the 60% rice mill feed diet than for the broiler litter diet.
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Table 7. Effects of replacing broiler litter with rice mill feed on apparent nutrient digestibilities in beef cattle (Exp. 4)
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Discussion
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The nutrient composition of the broiler litter (Table 1
) was similar to previously published values (Pugh et al., 1994; Rankins et al., 2002). Nutrient composition of the rice mill feed used in the present experiments was quite similar to those reported by Brazle and Coffey (1990). They reported 55% NDF and 39% ADF in the rice mill feed fed to heifers. Waller (2002) lists the nutrient content of rice mill feed as 53% ADF, 6.7% CP, and 80.9% OM. Rice mill feed used in the present experiments contained considerably less ADF but similar concentrations of CP and OM. Nevertheless, it is important to recognize that extreme variation can exist with respect to the nutrient content of alternative feeds (Rankins, 2002).
Average daily gains by steers consuming diets containing broiler litter in both Exp. 1 and 3 (0.9 and 1.0 kg/d, respectively) were similar to previously reported gains by cattle consuming similar diets (Gurung and Rankins, 2001). Rankins et al. (2002) indicated that diets containing 50% broiler litter should produce gains of approximately 1.0 kg/d with a G:F of 0.10 to 0.12. The G:F in Exp. 1 and 3 was 0.07 to 0.08, slightly below anticipated values; however, cattle used in the present experiments were quite large with ending weights heavier than 375 kg.
In Exp. 1, steers consuming 50% rice mill feed gained faster than those consuming the broiler litter-based diet. Similarly, in Exp. 3 steers fed 50% rice mill feed gained faster than did steers consuming broiler litter. Thus, with either energy source (corn or soyhulls), rice mill feed produced faster gains than did broiler litter. Steers consuming rice mill feed in this experiment gained much faster than did cattle fed rice mill feed in the only other published report (Brazle and Coffey, 1990). These workers reported ADG of 0.41 kg/d for heifers fed 67% rice mill feed and 33% dehydrated alfalfa pellets, a diet which would have contained substantially less energy than diets used in the present studies. Brazle and Coffey (1990) suggested that the fiber associated with the rice mill feed used in their study was not sufficient to maintain optimal ruminal function due to small particle size. It has been well documented that cattle consuming broiler litter-based diets need at least 0.5% of BW as long-stem fiber per day (Rankins et al., 2002). Based on the lower consumption of hay by cattle consuming diets containing rice mill feed, the fiber associated with rice mill feed appears to be more effective than fiber in broiler litter. This seemed to be more important when corn was the energy source than when soyhulls were used. Based on the greater NDF associated with soyhulls (Table 6) compared with corn, this would be expected.
Based on rice mill feed containing 66% rice hulls and 34% rice bran one would calculate that the diets fed in Exp. 1 and 3 (40:60, 50:50, 60:40 and 70:30) contained approximately 27, 33, 40, and 47% rice hulls and 13, 17, 20, and 23% rice bran, respectively. Noland and Gainer (1953) reported that animal performance declined when rice hull concentration of the diet exceeded 15%, and that when rice hulls were included at 50%, cattle gained 0.21 kg/d. In this work (Exp. 3) steers consuming 47% rice hulls (70:30 dietary treatment) gained 1.02 kg/d for 112 d; however, the rice hulls in rice mill feed are ground. White (1966) reported that cattle consuming a sudangrass hay diet gained more than those consuming a rice hull and sudangrass hay diet when up to 40% of the sudangrass was replaced with rice hulls. Several researchers have shown that cattle can be fed diets containing up to 23% rice bran (White and Davis, 1962; White, 1965). The limiting factor associated with rice bran is its fat content, which is approximately 15% (NRC, 1996).
Nutrient composition of diets fed for the two digestibility studies are shown in Tables 3 and 6. Organic matter content of all diets was low as a result of the large concentrations of ash in both broiler litter and rice mill feed (Table 3). This was also reflected in the low GE values for all diets. Similar trends were observed in Exp. 4 (Table 6). The fiber content (NDF and ADF) was greater in diets containing soyhulls than in those containing corn; however, it is a highly digestible fiber based on cattle performance (Tables 2 and 5). The values warranting the most concern are the CP concentrations of the diets. All combinations of rice mill feed and corn contained less than 7% CP (Table 3). The NRC (1996) indicated that the CP requirement of a 327-kg steer (554 kg anticipated slaughter weight) gaining 1.0 kg/d is 10.3% of the diet with a predicted DMI of 8.9 kg/d. In Exp. 1, steers fed the 60:40 diet consumed 11.2 kg/d (1.1 times times NRC requirement), thus their daily protein intake was 0.83 kg/d, which was 91% of the NRC requirement. Similar calculations for the 50:50 and 40:60 diets yielded 86% and 89% of their protein requirement, respectively. In Exp. 3, where corn was replaced with soyhulls, similar calculations for the 70:30, 60:40, and 50:50 diets yielded 134, 146 and 144%, respectively. The difference in ADG between Exp. 1 and Exp. 3 can mainly be attributed to these CP differences. The soyhulls made a better addition to the diets of the steers fed in our study, simply because soyhulls contain more CP than corn. Additional protein should be added before rice mill feed is fed to lighter weight calves. Lighter-weight calves require more protein (percentage of diet) and would have a lesser ability to compensate for the decreased protein content with an increased consumption like the calves in these studies did. Calves in these experiments were consuming in excess of 3% of BW daily for 112 d.
In Exp. 2, no differences were detected in apparent nutrient digestibilities (Table 4); however, in Exp. 4 (Table 7), differences were detected for DMI, NDF, and CP digestibilities. In Exp. 4, steers consuming rice mill feed had greater DMI than steers consuming broiler litter. Apparent NDF, DM, OM, GE, and ADF digestibilities tended to be lowest for the diet containing 70% rice mill feed. No other published data is available for rice mill feed; however, White (1966) reported that DM digestibility of diets containing 40% rice hulls was 20 units less than diets containing 40% sudangrass hay. The crude fiber fraction was reported to have a digestion coefficient of only 8.6% (White, 1966). When the dietary concentration of rice hulls was reduced from 40 to 20%, digestibility of rice hull diets was still less than that of the sudangrass hay diet (White, 1966). In another study, White et al., (1971) reported that the digestibilities of 5 and 20% rice hull diets were similar to those containing rice straw or alfalfa hay at the same level.
White (1966) observed diarrhea, bloat, and the excretion of bloody mucus when rice hulls were fed to cattle in a finishing experiment. Those same cattle consuming rice hulls also were observed eating feces on several occasions, and one of the cattle died after several days of being fed the rice hull diet. After a histological examination, the steer was found to have a tightly packed rumen. No digestive problems (i.e., diarrhea, bloat, or coprophagy) were observed during Exp. 1, 2 or 4. In Exp. 3, one pen of five steers consuming 70% rice mill feed, which contained 47% rice hulls, had two calves that were affected by bloat. One died and the other steer showed signs of rumen distention, but did not die or show any more signs of illness. These problems occurred after consuming the diets for approximately 60 d. The other pen of calves consuming the 70:30 diet showed no evidence of bloat. It should also be noted that soyhulls have been shown to be responsible for an increased incidence of bloat. Even though large concentrations of rice hulls were fed in the present experiments (i.e., 27 to 47%), no problems with compaction or other digestive disorders were observed. In the present experiments, the rice hull fraction of the rice mill feed was ground. Nearly all previous research has been conducted with whole (not ground) rice hulls. It would seem that the physical form of the rice hulls is very important for optimal utilization of this by-product.
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Implications
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Rice mill feed can be used to replace broiler litter in backgrounding diets for beef cattle. Rice mill feed can be fed up to 60% of the dietary dry matter for 112 d, with no digestive problems. Both soyhulls and corn produce adequate gains when mixed with rice mill feed; however, for lighter-weight calves, the crude protien content of the diet may need further attention.
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Footnotes
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1 Present address: Cargill, Animal Nutrition, 3250 Fitzpatrick Ave., Mongomery, AL 26108 
2 Correspondence: 303A Upchurch Hall (phone: 334-844-1546; fax: 334-844-1519; e-mail: drankins{at}aces.edu).
Received for publication December 9, 2003.
Accepted for publication April 8, 2004.
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Literature Cited
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AOAC. 1995. Official Methods of Analysis. 16th ed. Assoc. Offic. Anal. Chem., Arlington, VA.
Brazle, F. K., and K. P. Coffey. 1990. Rice Mill Feed as a Feed for Growing Cattle. Southeast Kansas Branch Stn., Report of Progress No. 599, Manhattan, KS.
Goering, H. K., and P. J. Van Soest. 1970. Forage Fiber Analyses (Apparatus, Reagents, Procedures and Some Applications) Agric. Handbook No 379. ARS, USDA, Washington, DC.
Gurung, N. K., and D. L. Rankins, Jr. 2001. Use of soybean hulls in broiler litter-based diets fed to beef cattle. J. Appl. Anim. Res. 19:193–201.
NRC. 1996. Nutrient Requirements of Beef Cattle. 7th rev. ed. Natl. Acad. Press, Washington, DC.
Noland, P. A., and J. H. Gainer. 1953. The use of rice hulls as a roughage for wintering steers and for gestating lactating ewes. Arkansas Agric. Exp. Stn. Bull. 538, Fayetteville, AR.
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Rankins, D. L., Jr. 2002. The importance of by-products to the U. S. beef industry. Food Anim. Pract. 18:207–211.
Rankins, D. L., Jr., J. T. Eason, and T. A. McCaskey. 1993. Nutritional and toxicological evaluation of three deep-stacking methods for the processing of broiler litter as a foodstuff for beef cattle. Anim. Prod. 56:321–326.
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Steel, R. G. D., and J. H. Torrie. 1980. Principles and Procedures of Statistics: A Biometrical Approach. 2nd ed. McGraw-Hill Book Co., New York.
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White, T. W. 1965. Rice bran in beef cattle fattening rations. Louisiana Agric. Exp. Stn. Bull. 600, Baton Rouge.
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White, T. W., and J. H. Davis. 1962. Source and level of nitrogen and energy for wintering and fattening weanling calves. Page 146 in Louisana Agric. Exp. Stn. Rice Exp. Stn. 55th Ann. Rep., Baton Rouge.
White, T. W., and R. Habetz. 1969. Broken rice and rice bran compared to grain sorghum for fattening steers. Pages 238–240 in Louisiana Agric. Exp. Stn. Rice Exp. Sta. 61st Ann. Rep., Baton Rouge.
White, T. W. and F. G. Hembry. 1982. Effect of roughage source and level of digestibility and rates of grain passage by steers. J. Anim. Sci. 55(Suppl. 1):3.
White, T. W., and F. G. Hembry. 1985. Rice by-products in ruminant rations. Page 771 in Louisiana Agric. Exp. Stn. Bull., Baton Rouge.
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Abstract
Introduction
