J. Anim Sci. 2008. 86:916-922. doi:10.2527/jas.2007-0491
© 2008 American Society of Animal Science
Influence of dry-rolling and tempering agent addition during the steam-flaking of sorghum grain on its feeding value for feedlot cattle
R. A. Zinn1,
E. G. Alverez2,
M. Montano2 and
J. Salinas-Chavira3
Department of Animal Science, University of California, Davis 95616
 |
Abstract
|
|---|
Two experiments were conducted to evaluate the influence of dry-rolling (DRS) and tempering agent (TA) addition during the steam-flaking of grain sorghum (SFS) for feedlot cattle. Five dietary treatments were compared: 1) DRS; 2) SFS, no TA; 3) SFS, 0.275 mg/kg of TA; 4) SFS, 1.375 mg/kg of TA; and 5) SFS, 2.750 mg/kg of TA. Bulk densities of DRS and SFS were 0.48 and 0.36 kg/L, respectively. Diets contained 70.6% grain sorghum (DM basis). One hundred fifty crossbred steers (336 kg of BW) were used in a 115-d finishing experiment to evaluate treatment effects on feedlot performance. Body weight gain averaged 1.49 kg/d and was not affected (P = 0.47) by treatments. The SFS reduced (P < 0.01) DMI (9%) and enhanced (P < 0.01) G:F (13%) and the NEm and NEg value of the diet (9 and 11%, respectively). Use of a TA before flaking sorghum did not influence (P > 0.20) cattle growth performance or NEm or NEg value of the diet. Given that the NEm and NEg values of DRS are 2.00 and 1.35 Mcal/kg, respectively (NRC, 1996
), the corresponding values for SFS were 2.28 and 1.59 Mcal/kg. Five steers (397 kg of BW) with ruminal and duodenal cannulas were used in a 5 x 5 Latin square design to evaluate treatment effects on digestive function. Ruminal digestion of OM and starch was greater (14 and 16%, respectively; P < 0.01) for SFS vs. DRS. Steam-flaking sorghum increased (P < 0.01) postruminal digestion of OM (11%), N (10%), and starch (25%) and total tract digestion (P < 0.01) of OM (8.3%), N (8.2%), and starch (8.9%). Grain processing did not affect (P > 0.20) ruminal pH or VFA molar proportions. There was a cubic component (P < 0.10) to level of TA on ruminal pH and VFA molar proportions, with values being optimal at 1.375 mg/kg of tempering agent. It is concluded that steam-flaking grain sorghum will increase its NE value for maintenance and gain (14 and 18%, respectively) and enhance the MP value of the diet due to greater intestinal N digestion. The use of a TA to enhance the mechanical efficiency of the flaking process may not otherwise benefit the feeding value of sorghum.
Key Words: sorghum • tempering • steam-flake • performance • digestion
|
INTRODUCTION
|
|---|
Tempering is a chemically facilitated process by which moisture is added to grain before further processing. Tempering the grains before steam-flaking has 2 advantages: 1) it improves the quality of flake grains, and 2) it improves utilization of grain by the animal.
Moisture uptake softens the grain, thereby reducing processing time and energy expenditure needed to produce a quality flake. Furthermore, the greater moisture uptake due to tempering may improve the strength or integrity of the flake, reducing dustiness and fines (McDonough et al., 1998). Although tempering has increased the NE value of dry-rolled corn, increasing moisture content of grain, per se, may not have an important influence on the NE value of steam-flaked grain (Zinn, 1988, 1990). Tempering steam-flaked corn did not influence ruminal or total tract digestion of starch but increased ruminal microbial efficiency. Also, greater starch gelatinization has been obtained with tempered than nontempered flakes of grain sorghum (McDonough et al., 1998). The utilization by the animal of grain sorghum is improved by steam-flaking. Theurer et al. (1999) found that sorghum starch digestibilities by steers in all segments of the digestive tract were improved by steam-flaking vs. dry-rolling.
The beneficial effect of tempering on ruminal microbial efficiency (Zinn, 1988) may have been due to the sarsaponin surfactants contained in the tempering agent (TA). Grobner et al. (1982) and Zinn et al. (1983) noted increased ruminal microbial efficiency with sarsaponin supplementation.
Application of a surfactant-based TA during tempering improved animal performance with barley (Wang et al., 2003) and corn (Zinn et al., 1998). However, the influence of tempering using saponin-derived surfactant agents on the feeding value of steam-flaked sorghum in feedlot steers has not been evaluated. The objective of this study was to determine the influence of dry-rolling and TA addition before flaking on the feeding value of grain sorghum for feedlot cattle.
|
MATERIALS AND METHODS
|
|---|
All procedures involving animal care and management were in accordance with and approved by the University of California, Davis Animal Use and Care Committee.
Exp. 1
Animals and Diets.
One hundred fifty crossbred yearling steers (approximately 25% Brahman breed with the remainder represented by Hereford, Angus, Shorthorn, and Charolais breeds in various proportions) with an average initial BW of 336 kg were used in a 115-d experiment to evaluate the influence of tempering on the feeding value of SFS. Steers were blocked by BW and randomly assigned within BW groups to 25 pens (6 steers per pen). Pens were 43 m2 with 22 m2 of overhead shade. Five dietary treatments were compared: 1) dry-rolled sorghum (DRS); 2) steam-flaked sorghum (SFS), no TA; 3) SFS with 0.275 mg/kg of TA (SarTemp, SarTec, Anoka, MN); 4) SFS with 1.375 mg/kg of TA; and 5) SFS with 2.750 mg/kg of TA. Composition of the basal diet is shown in Table 1. Diets were prepared at weekly intervals and stored in plywood boxes located in front of each pen. Steers were allowed ad libitum access to their experimental diets. Fresh feed was provided twice daily. Steers were implanted with Synovex-S (Fort Dodge Animal Health, Fort Dodge, IA).
Sorghum Processing.
Dry-rolled sorghum was processed through 41 x 61 cm corrugated rolls with the tension adjusted to produce a DRS bulk density 0.48 kg/L. In the production of SFS, water (0.075 L/kg of sorghum) plus the corresponding amount of TA were sprayed on the sorghum in a continuous flow system as it was augered into a holding bin located directly above the steam chest. Retention time of sorghum in the holding bin was approximately 30 min. Retention time of sorghum in the steam chest was also 30 min.
The SFS was prepared as follows. A chest situated directly above the rollers (46 x 61 cm corrugated rolls) was filled to capacity (441 kg) with sorghum and then brought to a constant temperature of 102°C using steam at atmospheric pressure. The sorghum was steamed for approximately 20 min before beginning the rollers. The first approximately 441 kg of SFS was allowed to pass from the rollers before material was collected for use in the experiment. This preliminary period served for warming the rollers and for adjusting the tension of the rollers to provide a flake with a density of 0.36 kg/L. The SFS was allowed to air-dry before it was fed.
Estimation of Dietary NE.
Energy gain (EG) was calculated by the equation: EG = ADG1.097 0.0493W0.75, where EG = the daily energy deposited (Mcal/d) and W = the mean shrunk BW (kg; NRC, 1984). Maintenance energy (EM) was calculated by the equation: EM = 0.077W0.75 (Lofgreen and Garrett, 1968). Dietary NEg was derived from NEm by the equation: NEg = 0.877(NEm) –0.41 (NRC, 1984; Zinn, 1987). Dry matter intake is related to energy requirements and dietary NEm according to the equation: DMI = EG/(0.877NEm – 0.41) and can be resolved for estimation of dietary NE by means of the quadratic formula:
where x = NEm; a = –0.41(EM); b = 0.877(EM) + 0.41(DMI) + EG; and c = –0.877(DMI) (Zinn et al., 1998).
Carcass Data.
Hot carcass weights were obtained at the time of slaughter. After the carcasses were chilled for 48 h, the following measurements were obtained: 1) LM area (ribeye area), by direct grid reading of the eye muscle at the 12th rib; 2) s.c. fat over the eye muscle at the 12th rib taken at a location 3/4 the lateral length from the chine bone end (adjusted by eye for unusual fat distribution); 3) KPH as a percentage of HCW; and 4) marbling score (USDA, 1965; using 3.0 as minimum slight, 4.0 as minimum small, etc.).
Statistical Design and Analysis.
For calculating steer performance, initial and final full BW were reduced by 4% to account for digestive tract fill. Pens were used as the experimental units. The experiment data were analyzed as a randomized complete block design experiment, with 5 treatments and 5 blocks (Hicks, 1973). Treatment effects were tested for the following contrasts: DRS vs. SFS and the linear, quadratic, and cubic effects of the TA level.
Exp. 2
Animals and Sampling.
Five crossbred steers (397 kg) with cannulas in the rumen and proximal duodenum (Zinn and Plascencia, 1993) were used in 5 x 5 Latin square experiment to study treatment effects on the characteristics of digestion. Treatments were the same as those used in Exp. 1 (Table 1
), with 0.40% chromic oxide added as a digesta marker. Steers were maintained in individual pens with access to water at all times. Diets were fed at 0800 and 2000 daily. Dry matter intake was restricted to 6.3 kg/d (1.6% of BW daily). Experimental periods were 2 wk, with 10 d for diet adjustment and 4 d for collection. During collection, duodenal and fecal samples were taken twice daily as follows: d 1, 0750 and 1350; d 2, 0900 and 1500; d 3, 1050 and 1650, and d 4, 1200 and 1800. Individual samples consisted of approximately 700 mL of duodenal chyme and 200 g (wet basis) of fecal material. Samples of each steer and within each collection period were composited for analysis. During the final day of each collection period, ruminal samples were obtained from each steer via ruminal cannula at 4 h after feeding. Ruminal fluid pH was determined on fresh samples. Samples were strained through 4 layers of cheesecloth. Two milliliters of freshly prepared 25% (wt/vol) meta-phosphoric acid was added to 8 mL of strained ruminal fluid. Samples were then centrifuged (17,000 x g for 10 min), and supernatant fluid was stored at –20°C for VFA analysis. Upon completion of the experiment, ruminal fluid was obtained via the ruminal cannula from all steers and composited for isolation of ruminal bacteria via differential centrifugation (Bergen et al., 1968).
Sample Analysis and Calculations.
Samples were subjected to all or part of the following analysis: DM (oven-drying at 105°C until no further weight loss), ash, ammonia N, Kjeldahl N (AOAC, 1984), NDF (Goering and Van Soest, 1970; adjusted for insoluble ash), chromic oxide (Hill and Anderson, 1958), purines (Zinn and Owens, 1986), and starch (Zinn, 1990). Microbial OM and microbial N leaving the abomasum were calculated using purines as a microbial marker (Zinn and Owens, 1986). Organic matter fermented in the rumen was considered equal to OM intake minus the difference between the amount of total OM reaching the duodenum and microbial OM reaching the duodenum. Feed N escape to the small intestine was considered equal to total N leaving the abomasum minus ammonia N and microbial N and thus included any endogenous additions. Methane production (mol/mol of glucose equivalent fermented) was estimated based on the theoretical fermentation balance for observed molar distribution of VFA (Wolin, 1960).
Statistical Analysis.
Data were analyzed as a 5 x 5 Latin square (Hicks, 1973). Treatment effects were tested using the following contrasts: DRS vs. SFS and the linear, quadratic, and cubic effects of the TA level.
|
RESULTS AND DISCUSSION
|
|---|
Treatment effects on feedlot performance and the estimated NE value of the diet (Exp. 1) are shown in Table 2. Body weight gain averaged 1.49 kg/d and was not affected (P = 0.47) by treatments. Steam-flaking sorghum reduced (P < 0.01) DMI (9%) and enhanced (P < 0.01) G:F (13%) and the NEm and NEg values of the diet (9 and 11%, respectively). Tempering before flaking sorghum did not influence (P > 0.20) cattle growth performance or NEm and NEg values of the diet.
View this table:
[in this window]
[in a new window]
|
Table 2. Influence of tempering before flaking on growth performance of feedlot steers fed sorghum-based finishing diets (Exp. 1)
|
|
The interaction of varying levels of moisture addition via tempering before flaking on the feeding value of SFS has not been extensively evaluated. Consistent with the present research, Zinn (1988) and Sindt et al. (2006) also did not observe an influence of tempering before flaking corn on ADG and G:F.
Apparently, the primary determinate for enhancement in feeding value of steam-flaked grain is the degree of shear of the starch granules that occurs as grain passes through rolls (Zinn et al., 2002). For example, Zinn (1990) observed that when corn was steamed for a constant time (34 min at 105°C), increasing the pressure on the rolls to produce flake densities of 0.41, 0.36, and 0.31 kg/L linearly increased extent of starch digestion both in the rumen and in the total digestive tract. In contrast, doubling the steaming time (67 vs. 34 min) at 105°C before flaking to a density of 0.31 kg/L failed to increase either ruminal or total tract starch digestion, notwithstanding kernel moisture was increased (18%). In contrast, tempering before cold-rolling (in absence of steam) has enhanced ADG, G:F, and dietary NE in cattle fed corn-based finishing diets (Zinn, 1988; Bradshaw et al., 1996) and has enhanced G:F and dietary NE in cattle fed barley-based finishing diets (Wang et al., 2003).
Given that the NEm and NEg values of DRS are 2.00 and 1.35 Mcal/kg, respectively (NRC, 1996), the corresponding values for SFS are 2.28 and 1.59 Mcal/kg. The NEm value for SFS is in good agreement with Zinn (1991; 2.34 Mcal/kg) but is greater (4.6%) than the current tabular value (2.18 Mcal/kg; NRC, 1996). The NRC (1996) has given SFS 92% the value of steam-flaked corn. This relationship is consistent with Zinn (1991).
Treatment effects on carcass characteristics are shown in Table 3. There were no treatment effects on dressing percentage (P = 0.87), KPH (P = 0.83), LM area (P = 0.42), marbling score (P = 0.50), or retail yield (P = 0.29). However, level of inclusion of TA tended to affect (quadratic component, P < 0.10) fat thickness and liver abscess (linear component, P < 0.10). With corn-based diets, tempering before flaking likewise did not affect carcass characteristics (Zinn, 1988).
View this table:
[in this window]
[in a new window]
|
Table 3. Influence of tempering before flaking on carcass characteristics of feedlot steers fed sorghum-based finishing diets (Exp. 1)
|
|
Treatment effects on digestive function (Exp. 2) are shown in Table 4. The BW of animals in this experiment was 397 kg, and the DMI was adjusted to 6.3 kg/d (1.59% of BW). As was expected (Theurer et al., 1999), steam-flaking sorghum increased (P < 0.01) ruminal digestion of OM (14%) and starch (16%) compared with DRS. Similar results have been observed in comparisons of ruminal starch digestion of steam-flaked vs. dry-rolled corn (Zinn, 1988; Zinn et al., 1998; Cooper et al., 2002).
View this table:
[in this window]
[in a new window]
|
Table 4. Influence of tempering before flaking on characteristics of ruminal and total digestion of feedlot steers fed sorghum-based finishing diets (Exp. 2)
|
|
There were no treatment effects (P = 0.66) on ruminal feed N digestion. Nevertheless, ruminal N efficiency (nonammonia N flow to the small intestine/N intake) was greater (8.6%, P < 0.01) for SFS than for DRS. This effect was due to greater (9.4%, P < 0.05) flow of microbial N to the small intestine with SFS that is associated with the increased ruminal OM digestion. Steam-flaking did not affect (P = 0.64) microbial efficiency (g of microbial N/kg of OM fermented). Likewise, Theurer et al. (1999) also observed 10% greater microbial N flow to the small intestine with SFS than with DRS. Similar responses were also observed for steam-flaked vs. dry-rolled corn (Zinn, 1988; Zinn et al., 1998). Microbial efficiency was affected (quadratic component, P < 0.05) by level of TA. The basis for this response is not certain. There were no treatment effects on ruminal digestion of NDF (P = 0.37) or on apparent ruminal digestion of feed N (P = 0.62).
Steam-flaking sorghum increased (P < 0.01) postruminal digestion of OM (11%), N (10%), and starch (25%) and total tract digestion (P < 0.01) of OM (8.3%), N (8.2%), and starch (8.9%). Increased postruminal digestion of OM, N, and starch has been a consistent response to steam-flaking sorghum (Swingle et al., 1999; Theurer et al., 1999) and corn (Zinn, 1988, 1990; Barajas and Zinn, 1998; Zinn et al., 1998). Rooney and Pflugfelder (1986) identified protein bodies and the protein matrix surrounding starch granules as the major cause of lower digestibility in grain sorghum. Zinn et al. (2002) observed that granule shear during flaking, particularly of the protein-rich horny endosperm, exposes more of the protein to the postruminal proteolytic process; that in turn increases exposure of associated starch to the amylolytic process. Hence, a linkage between postruminal protein and starch digestibility would be expected.
Consistent with previous studies (Zinn, 1991; Swingle et al., 1999; Theurer et al., 1999), total tract starch digestion was nearly (99.3%) complete for SFS. However, total tract starch digestion for DRS (91.2%) was less than reported by Theurer et al. (1999; 96.5%). Applying the equation of Zinn et al. (2007; total tract starch digestion, % = 100 {1 – [(0.938 – 0.497 FN + 0.0852 FN2) FS/DS]}, where FN = percentage of fecal N and FS and DS = percentages of starch in feces and diet), total tract starch digestion was predicted to be 99.2 and 92.6% for SFS and DRS, respectively, in good agreement with our observations.
Treatment effects on ruminal pH and VFA molar proportions are shown in Table 5. Grain processing did not affect (P > 0.20) ruminal pH or VFA molar proportions. A comparison of effects of steam-flaking vs. dry-rolling grain sorghum on ruminal pH and VFA molar proportions in feedlot cattle has not been reported previously in the literature. In the case of corn grain, effects of steam-flaking on ruminal pH and VFA molar proportions have not been consistent. In some studies, steam-flaking did not affect ruminal pH or VFA molar proportions (Lee et al., 1982; Zinn et al., 1998), whereas in others (Zinn, 1987; Zinn et al., 1995), ruminal pH decreased and molar proportions of propionate were increased with steam-flaking. Level of TA addition to SFS affected (cubic component) ruminal pH (P < 0.10) and molar proportions of acetate (P < 0.05), propionate (P < 0.10), and estimated methane production (P < 0.05). Optimal response in terms of estimated methane energy loss was observed at the 1.375 mg/kg level of TA addition. The basis for this effect is not certain. Its practical significance in terms of dietary NE was not apparent in the growth performance response (Exp. 1).
View this table:
[in this window]
[in a new window]
|
Table 5. Influence of tempering before flaking on ruminal pH and VFA molar proportions of feedlot steers fed sorghum-based finishing diets (Exp. 2)
|
|
In conclusion, steam-flaking sorghum will increase its comparative NE values for maintenance and gain (14 and 18%, respectively). Steam-flaking sorghum will enhance the MP value of the diet (14%) due to greater intestinal N digestion and greater net microbial N flow to the small intestine. The use of a TA to enhance the mechanical efficiency of the flaking process may have little or no effect on ruminal and total tract OM and starch digestion.
|
Footnotes
|
|---|
2 Current address: Universidad Autónoma de Baja California, Mexicali, Mexico. 
3 Current address: Universidad Autónoma de Tamaulipas, Cd. Victoria, Mexico.
1 Corresponding author: razinn{at}ucdavis.edu
Received for publication August 2, 2007.
Accepted for publication November 30, 2007.
|
LITERATURE CITED
|
|---|
AOAC. 1984. Official Methods of Analysis. 14th ed. Assoc. Off. Anal. Chem., Arlington, VA.
Barajas, R., and R. A. Zinn. 1998. The feeding value of dry-rolled and steam-flaked corn in finishing diets for feedlot cattle: Influence of protein supplementation. J. Anim. Sci. 76:1744–1752.[Abstract/Free Full Text]
Bergen, W. G., D. B. Purser, and J. H. Cline. 1968. Effect of ration on the nutritive quality of rumen microbial protein. J. Anim. Sci. 27:1497–1501.[Abstract/Free Full Text]
Bradshaw, W. L., D. D. Hinman, R. C. Bull, D. O. Everson, and S. J. Sorensen. 1996. Effects of barley variety and processing methods on feedlot steer performance and carcass characteristics. J. Anim. Sci. 74:18–24.[Abstract]
Cooper, R. J., C. T. Milton, T. J. Klopfenstein, T. L. Scott, C. B. Wilson, and R. A. Mass. 2002. Effect of corn processing on starch digestion and bacterial protein flow in finishing cattle. J. Anim. Sci. 80:797–804.[Abstract/Free Full Text]
Goering, H. K., and P. J. Van Soest. 1970. Forage Fiber Analyses (Apparatus, Reagents, Procedures, and Some Applications). Agric. Handb. No. 379. ARS-USDA, Washington, DC.
Grobner, M. A., D. E. Johnson, S. R. Goodhall, and D. A. Benz. 1982. Sarsaponin effects on in vitro continuous flow fermentation of a high grain diet. West. Sec. Am. Soc. Anim. Sci. 33:64–68.
Hicks, C. R. 1973. Fundamental Concepts in the Design of Experiments. Holt, Rinehart and Winston Inc., New York, NY.
Hill, F. N., and D. L. Anderson. 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutr. 64:587–603.[Abstract/Free Full Text]
Lee, R. W., M. L. Galyean, and G. P. Lofgreen. 1982. Effects of mixing whole shelled and steam flaked corn in finishing diets on feedlot performance and site and extent of digestion in beef steers. J. Anim. Sci. 55:475–483.[Abstract/Free Full Text]
Lofgreen, G. P., and W. N. Garrett. 1968. A system for expressing net energy requirements and feed values for growing and finishing beef cattle. J. Anim. Sci. 27:793–806.[Abstract/Free Full Text]
McDonough, C., B. J. Anderson, H. Acosta-Zuleta, and L. W. Rooney. 1998. Effect of conditioning agents on the structure of tempered and steam-flaked sorghum. Cereal Chem. 75:58–63.[CrossRef]
NRC. 1984. Nutrient Requirements of Beef Cattle. 6th rev. ed. Natl. Acad. Press, Washington, DC.
NRC. 1996. Nutrient Requirements of Beef Cattle. 7th rev. ed. Natl. Acad. Press, Washington, DC.
Rooney, L. W., and R. L. Pflugfelder. 1986. Factors affecting starch digestibility with special emphasis on sorghum and corn. J. Anim. Sci. 63:1607–1623.[Abstract/Free Full Text]
Sindt, J. J., J. S. Drouillard, E. C. Titgemeyer, S. P. Montgomery, E. R. Loe, B. E. Depenbusch, and P. H. Walz. 2006. Influence of steam-flaked corn moisture level and density on the site and extent of digestibility and feeding value for finishing cattle. J. Anim. Sci. 84:424–432.[Abstract/Free Full Text]
Swingle, R. S., T. P. Eck, C. B. Theurer, M. Delallata, M. H. Poore, and J. A. Moore. 1999. Flake density of steam-processed sorghum grain alters performance and sites of digestibility by growing-finishing steers. J. Anim. Sci. 77:1055–1065.[Abstract/Free Full Text]
Theurer, C. B., O. Lozano, A. Alio, A. Delgado-Elorduy, M. Sadik, J. T. Huber, and R. A. Zinn. 1999. Steam-processed corn and sorghum grain flaked at different densities alter ruminal, small intestinal, and total tract digestibility of starch by steers. J. Anim. Sci. 77:2824–2831.[Abstract/Free Full Text]
USDA. 1965. Official United States Standards for Grades of Carcass Beef. USDA, C&MS. Surg. Radiol. Anat. 99.
Wang, Y., D. Greer, and T. A. McAllister. 2003. Effects of moisture, roller setting, and saponin-based surfactant on barley processing, ruminal degradation of barley, and growth performance by feedlot steers. J. Anim. Sci. 81:2145–2154.[Abstract/Free Full Text]
Wolin, M. J. 1960. A theoretical rumen fermentation balance. J. Dairy Sci. 43:1452–1459.[Abstract/Free Full Text]
Zinn, R. A. 1987. Influence of lasalocid and monensin plus tylosin on comparative feeding value of steam-flaked versus dry-rolled corn diets for feedlot cattle. J. Anim. Sci. 65:256–266.[Abstract/Free Full Text]
Zinn, R. A. 1988. Influence of tempering on the comparative feeding value of rolled and steam-flaked corn for feedlot steers. Proc. West. Sec. Am. Soc. Anim. Sci. 39:389–391.
Zinn, R. A. 1990. Influence of flake density on the comparative feeding value of steam-flaked corn for feedlot cattle. J. Anim. Sci. 68:767–775.[Abstract]
Zinn, R. A. 1991. Comparative feeding value of steam-flaked corn and sorghum in finishing diets supplemented with or without sodium bicarbonate. J. Anim. Sci. 69:905–916.[Abstract]
Zinn, R. A., C. F. Adams, and M. S. Tamayo. 1995. Interaction of feed intake level on comparative ruminal and total tract digestion of dry rolled and steam-flaked corn. J. Anim. Sci. 73:1239–1245.[Abstract]
Zinn, R. A., E. G. Alvarez, M. F. Montaño, A. Plascencia, and J. E. Ramirez. 1998. Influence of tempering on the feeding value of rolled corn in finishing diets for feedlot cattle. J. Anim. Sci. 76:2239–2246.[Abstract/Free Full Text]
Zinn, R. A., D. Axe, J. Dunbar, and B. Norman. 1983. Sarsaponin influence on performance and metabolism of light weight calves. Pages 87–92 in Calif. Feeders’ Day Rep., Univ. California, Davis.
Zinn, R. A., A. Barreras, L. Corona, F. N. Owens, and R. A. Ware. 2007. Starch digestion by feedlot cattle: Predictions from analysis of feed and fecal starch and nitrogen. J. Anim. Sci. 85:1727–1730.[Abstract/Free Full Text]
Zinn, R. A., and F. N. Owens. 1986. A rapid procedure for purine measurement and its use for estimating net ruminal protein synthesis. Can. J. Anim. Sci. 66:157–166.
Zinn, R. A., F. N. Owens, and R. A. Ware. 2002. Flaking corn: Processing mechanics, quality standards, and impacts on energy availability and performance of feedlot cattle. J. Anim. Sci. 80:1145–1156.[Abstract/Free Full Text]
Zinn, R. A., and A. Plascencia. 1993. Interaction of whole cottonseed and supplemental fat on digestive function in cattle. J. Anim. Sci. 71:11–17.[Abstract]
Top
Abstract
INTRODUCTION
