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Substitution of dry corn grain by rehydrated and ensiled corn grain, finely or coarsely ground, on performance of young bulls finished in feedlot

ABSTRACT

We investigated the effects of corn grain, finely or coarsely ground, rehydrated and ensiled to 35% moisture in substitution of dry corn grain on performance of beef cattle in the feedlot. Forty non-castrated young Angus crossbred bulls with average age of 13±1.4 months and average initial body weight (BW) of 374±14 kg. The experiment was conducted in blocks by weight, and bulls were randomly assigned into four groups of five animals each in a 2 × 2 factorial scheme. The factors evaluated were particle size (finely and coarsely ground) and two grain sources (dry ground corn and rehydrated corn grain silage). The treatments were diets containing dry corn grain, finely ground (DCF; 1.86 mm); dry corn grain, coarsely ground (DCC; 3.53 mm); rehydrated and ensiled corn grain, finely ground (RCF; 1.86 mm); and rehydrated and ensiled corn grain, coarsely ground (RCC; 3.53 mm). Initial BW, final BW, average daily gain (ADG), feed efficiency, and intake of dry matter (DMI), acid detergent fiber, and metabolizable energy were not affected by treatment. Ensiling corn grain decreased DMI by 10.3% (11.6 vs. 10.4 kg/d for dry and ensiled, respectively) and increased feed efficiency by 13.3% (0.13 vs. 0.15 kg/d for dry and ensiled, respectively), but there was no effect of particle size, grain source, and their interaction on ADG. Effects of particle size and grain source were observed for fecal starch and total tract starch digestion, with evidence that treatments containing rehydrated corn diets showed greater efficiency in the utilization of dietary starch. Animals fed RCF diets showed lower fecal starch losses of 37, 55, and 75% when compared with treatments RCC, DCF, and DCC, respectively. Our results suggested that ensiled rehydrated corn grain improves feed efficiency in substitution of dry corn grain. The finely and coarsely ground of rehydrated and ensiled corn grain increases the digestibility of starch for finishing cattle in feedlot.

corn grain; feed efficiency; feedlot; processing; reconstituted corn

1. Introduction

Corn is the main source of energy used to feed confined cattle. In Brazil, flint corn is the predominant type used (Oliveira and Millen, 2014Oliveira, C. A. and Millen, D. D. 2014. Survey of the nutritional recommendations and management practices adopted by feedlot cattle nutritionists in Brazil. Animal Feed Science and Technology 197:64-75. https://doi.org/10.1016/j.anifeedsci.2014.08.010
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; Pinto and Millen, 2019Pinto, A. C. J. and Millen, D. D. 2019. Nutritional recommendations and management practices adopted by feedlot cattle nutritionists: the 2016 Brazilian survey. Canadian Journal of Animal Science 99:392-407. https://doi.org/10.1139/cjas-2018-0031
https://doi.org/10.1139/cjas-2018-0031...
) and is known to have a lower degradability rate and, therefore, lower energy availability (Philippeau and Michalet-Doreau, 1997Philippeau, C. and Michalet-Doreau, B. 1997. Influence of genotype and stage of maturity of maize on rate of ruminal starch degradation. Animal Feed Science and Technology 68:25-35. https://doi.org/10.1016/S0377-8401(97)00042-4
https://doi.org/10.1016/S0377-8401(97)00...
; Correa et al., 2002Correa, C. E. S.; Shaver, R. D.; Pereira, M. N.; Lauer, J. G. and Kohn, K. 2002. Relationship between corn vitreousness and ruminal in situ starch degradability. Journal of Dairy Science 85:3008-3012. https://doi.org/10.3168/jds.S0022-0302(02)74386-5
https://doi.org/10.3168/jds.S0022-0302(0...
; Stock and Erickson, 2006Stock, R. A. and Erickson, G. E. 2006. Associative effects and management - combinations of processed grains. p.166-172. In: Proceedings of Cattle Grain Processing Symposium, Tulsa, OK.). Grain processing practices aimed at modifying its physical structure and increasing starch availability are necessary (Ferraretto et al., 2015Ferraretto, L. F.; Fredin, S. M. and Shaver, R. D. 2015. Influence of ensiling, exogenous protease addition, and bacterial inoculation on fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility in rehydrated and high-moisture corn. Journal of Dairy Science 98:7318-7327. https://doi.org/10.3168/jds.2015-9891
https://doi.org/10.3168/jds.2015-9891...
; González García et al., 2018González García, U. A.; Corona, L; Castrejon-Pineda, F.; Balcells, J.; Castelan Ortega, O. and Gonzalez-Ronquillo, M. 2018. A comparison of processed sorghum grain using different digestion techniques. Journal of Applied Animal Research 46:1-9. https://doi.org/10.1080/09712119.2016.1250642
https://doi.org/10.1080/09712119.2016.12...
; Silva et al., 2019Silva, N. C.; Nascimento, C. F.; Campos, V. M. A.; Alves, M. A. P.; Resende, F. D.; Daniel, J. L. P. and Siqueira, G. R. 2019. Influence of storage length and inoculation with Lactobacillus buchneri on the fermentation, aerobic stability, and ruminal degradability of high-moisture corn and rehydrated corn grain silage. Animal Feed Science and Technology 251:124-133. https://doi.org/10.1016/j.anifeedsci.2019.03.003
https://doi.org/10.1016/j.anifeedsci.201...
).

Thus, processing is critical and can range from coarser grinding to more efficient and optimizing methods such as ensiling grains harvested with high moisture content or rehydrating grain with moisture content reconstitution (Macken et al., 2006Macken, C. N.; Erickson, G. E.; Klopfenstein, T. J. and Stock, R. A. 2006. Effects of corn processing method and protein concentration in finishing diets containing wet corn gluten feed on cattle performance. The Professional Animal Scientist 22:14-22. https://doi.org/10.15232/S1080-7446(15)31056-1
https://doi.org/10.15232/S1080-7446(15)3...
; Ferraretto et al., 2014Ferraretto, L. F.; Taysom, K.; Taysom, D. M.; Shaver, R. D. and Hoffman, P. C. 2014. Relationships between dry matter content, ensiling, ammonia-nitrogen, and ruminal in vitro starch digestibility in high-moisture corn samples. Journal of Dairy Science 97:3221-3227. https://doi.org/10.3168/jds.2013-7680
https://doi.org/10.3168/jds.2013-7680...
; Silva et al., 2018Silva, M. R. H.; Jobim, C. C.; Neumann, M. and Osmari, M. P. 2018. Corn grain processing improves chemical composition and fermentative profile of rehydrated silage. Acta Scientiarum. Animal Sciences 40:e42564. https://doi.org/10.4025/actascianimsci.v40i1.42564
https://doi.org/10.4025/actascianimsci.v...
). Reducing particle size enhances energy availability, increases surface area for microbial colonization, and starch digestibility, consequently improving animal performance (McAllister et al., 2006McAllister, T. A.; Gibb, D. J.; Beauchemin, K. A. and Wang, Y. 2006. Starch type, structure and ruminal digestion. p.30-41. In: Cattle Grain Processing Symposium. Oklahoma State University, Tulsa, OK.; Owens and Soderlund, 2006Owens, F. and Soderlund, S. 2006. Ruminal and postruminal starch digestion by cattle. p.116-128. In: Cattle Grain Processing Symposium. Oklahoma State University, Tulsa, OK.; Zinn et al., 2007Zinn, R. A.; Barreras, A.; Corona, L.; Owens, F. N. and Ware, R. A. 2007. Starch digestion by feedlot cattle: Predictions from analysis of feed and fecal starch and nitrogen. Journal of Animal Science 85:1727-1730. https://doi.org/10.2527/jas.2006-556
https://doi.org/10.2527/jas.2006-556...
; Ferraretto et al., 2015Ferraretto, L. F.; Fredin, S. M. and Shaver, R. D. 2015. Influence of ensiling, exogenous protease addition, and bacterial inoculation on fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility in rehydrated and high-moisture corn. Journal of Dairy Science 98:7318-7327. https://doi.org/10.3168/jds.2015-9891
https://doi.org/10.3168/jds.2015-9891...
; Arcari et al., 2016Arcari, M. A.; Martins, C. M. M. R.; Tomazi, T.; Gonçalves, J. L. and Santos, M. V. 2016. Effect of substituting dry corn with rehydrated ensiled corn on dairy cow milk yield and nutrient digestibility. Animal Feed Science and Technology 221:167-173. https://doi.org/10.1016/j.anifeedsci.2016.08.005
https://doi.org/10.1016/j.anifeedsci.201...
). Reducing particle size, however, can reduce chewing and rumination, as well as increase passage rate (Cozannet et al., 2018Cozannet, P.; Lawlor, P. G.; Leterme, P.; Devillard, E.; Geraert, P. A.; Rouffineau, F. and Preynat, A. 2018. Reducing BW loss during lactation in sows: a meta-analysis on the use of a nonstarch polysaccharide-hydrolyzing enzyme supplement. Journal of Animal Science 96:2777-2788. https://doi.org/10.1093/jas/sky045
https://doi.org/10.1093/jas/sky045...
; González García et al., 2018González García, U. A.; Corona, L; Castrejon-Pineda, F.; Balcells, J.; Castelan Ortega, O. and Gonzalez-Ronquillo, M. 2018. A comparison of processed sorghum grain using different digestion techniques. Journal of Applied Animal Research 46:1-9. https://doi.org/10.1080/09712119.2016.1250642
https://doi.org/10.1080/09712119.2016.12...
).

Rehydrated and ensiled corn grain is an alternative to minimize some common problems in production systems that use corn as an energy source for beef cattle. This technology allows reducing and/or eliminating costs with fees and discounts, taxes, transportation, freight, and storage, as well as reducing losses from insect and rodent attacks, which is very common in dry corn storage (Macken et al., 2006Macken, C. N.; Erickson, G. E.; Klopfenstein, T. J. and Stock, R. A. 2006. Effects of corn processing method and protein concentration in finishing diets containing wet corn gluten feed on cattle performance. The Professional Animal Scientist 22:14-22. https://doi.org/10.15232/S1080-7446(15)31056-1
https://doi.org/10.15232/S1080-7446(15)3...
; Silva et al., 2018Silva, M. R. H.; Jobim, C. C.; Neumann, M. and Osmari, M. P. 2018. Corn grain processing improves chemical composition and fermentative profile of rehydrated silage. Acta Scientiarum. Animal Sciences 40:e42564. https://doi.org/10.4025/actascianimsci.v40i1.42564
https://doi.org/10.4025/actascianimsci.v...
; Paschoaloto et al., 2019Paschoaloto, J. R.; Guimarães, L. A.; Matos, E. M. A. and Villela, S. D. J. 2019. PSXII-22 Performance of Nellore bulls fed with rehydrated corn silage or rehydrated sorghum silage or sorghum grain in substitution of corn grain. Journal of Animal Science 97:419. https://doi.org/10.1093/jas/skz258.831
https://doi.org/10.1093/jas/skz258.831...
). In addition, there are possibilities of buying grains during periods of lower prices, especially in the harvest season, with economic appeal, providing a reduction in cattle production costs (Arcari et al., 2016Arcari, M. A.; Martins, C. M. M. R.; Tomazi, T.; Gonçalves, J. L. and Santos, M. V. 2016. Effect of substituting dry corn with rehydrated ensiled corn on dairy cow milk yield and nutrient digestibility. Animal Feed Science and Technology 221:167-173. https://doi.org/10.1016/j.anifeedsci.2016.08.005
https://doi.org/10.1016/j.anifeedsci.201...
).

Ensiling rehydrated corn grain is a strategy to improve starch digestibility (Owens et al., 1986Owens, F. N.; Zinn, R. A. and Kim, Y. K. 1986. Limits to starch digestion in the ruminant small intestine. Journal of Animal Science 63:1634-1648. https://doi.org/10.2527/jas1986.6351634x
https://doi.org/10.2527/jas1986.6351634x...
; Benton et al., 2005Benton, J. R.; Erickson, G. E.; Klopfenstein, T. J.; Macken, C. N. and Vander Pol, K. J. 2005. Effects of corn moisture and degradable intake protein concentration on finishing cattle performance. Nebraska Beef Cattle Reports. p.28-30.). During the storage period, the action of proteolytic bacteria and kernel proteases break down the protein matrix (Junges et al., 2017Junges, D.; Morais, G.; Spoto, M. H. F.; Santos, P. S.; Adesogan, A. T.; Nussio, L. G. and Daniel, J. L. P. 2017. Short communication: Influence of various proteolytic sources during fermentation of reconstituted corn grain silages. Journal of Dairy Science 100:9048-9051. https://doi.org/10.3168/jds.2017-12943
https://doi.org/10.3168/jds.2017-12943...
), increasing the availability of starch to animal digestion (Zinn et al., 2007Zinn, R. A.; Barreras, A.; Corona, L.; Owens, F. N. and Ware, R. A. 2007. Starch digestion by feedlot cattle: Predictions from analysis of feed and fecal starch and nitrogen. Journal of Animal Science 85:1727-1730. https://doi.org/10.2527/jas.2006-556
https://doi.org/10.2527/jas.2006-556...
; Hoffman et al., 2011Hoffman, P. C.; Esser, N. M.; Shaver, R. D.; Coblentz, W. K.; Scott, M. P.; Bodnar, A. L.; Schmidt, R. J. and Charley, R. C. 2011. Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn. Journal of Dairy Science 94:2465-2474. https://doi.org/10.3168/jds.2010-3562
https://doi.org/10.3168/jds.2010-3562...
; Ferraretto et al., 2015Ferraretto, L. F.; Fredin, S. M. and Shaver, R. D. 2015. Influence of ensiling, exogenous protease addition, and bacterial inoculation on fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility in rehydrated and high-moisture corn. Journal of Dairy Science 98:7318-7327. https://doi.org/10.3168/jds.2015-9891
https://doi.org/10.3168/jds.2015-9891...
).

In recent meta-analyses about the effect of ensiling on the feeding value of flint corn grain for feedlot beef cattle, Jacovaci et al. (2021)Jacovaci, F. A.; Salvo, P. A. R.; Jobim, C. C. and Daniel, J. L. P. 2021. Effect of ensiling on the feeding value of flint corn grain for feedlot beef cattle: A meta-analysis. Revista Brasileira de Zootecnia 50:e20200111. https://doi.org/10.37496/rbz5020200111
https://doi.org/10.37496/rbz5020200111...
found that the inclusion of ensiled corn in diets increased total tract digestibility of DM by 4.59% and starch by 3.33%, decreased DM intake by 14.1%, and increased feed efficiency by 18.3% but did not affect average daily gain (ADG). However, these benefits of grain ensiling are based on three major factors (Gomes et al., 2020Gomes, A. L. M.; Bueno, A. V. I.; Jacovaci, F. A.; Donadel, G.; Ferraretto, L. F.; Nussio, L. G.; Jobim, C. C. and Daniel, J. L. P. 2020. Effects of processing, moisture, and storage length on the fermentation profile, particle size, and ruminal disappearance of reconstituted corn grain. Journal of Animal Science 98:skaa332. https://doi.org/10.1093/jas/skaa332
https://doi.org/10.1093/jas/skaa332...
): moisture content (Owens et al., 1997Owens, F. N.; Secrist, D. S.; Hill, W. J. and Gill, D. R. 1997. The effect of grain source and grain processing on performance of feedlot cattle: a review. Journal of Animal Science 75:868-879. https://doi.org/10.2527/1997.753868x
https://doi.org/10.2527/1997.753868x...
), particle size (Rémond et al., 2004Rémond, D.; Cabrera-Estrada, J. I.; Champion, M.; Chauveau, B.; Coudure, R. and Poncet, C. 2004. Effect of corn particle size on site and extent of starch digestion in lactating dairy cows. Journal of Dairy Science 87:1389-1399. https://doi.org/10.3168/jds.S0022-0302(04)73288-9
https://doi.org/10.3168/jds.S0022-0302(0...
), and length of storage time (Hoffman et al., 2011Hoffman, P. C.; Esser, N. M.; Shaver, R. D.; Coblentz, W. K.; Scott, M. P.; Bodnar, A. L.; Schmidt, R. J. and Charley, R. C. 2011. Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn. Journal of Dairy Science 94:2465-2474. https://doi.org/10.3168/jds.2010-3562
https://doi.org/10.3168/jds.2010-3562...
).

We hypothesized that mean particle size (MPS) and ensiling process of corn grain could increase animal performance by increasing the digestibility of starch, feed efficiency, and average daily gain (ADG) to allow a complete substitution of cracked dry corn grain. The objective was to evaluate the performance of young bulls fed finishing diets composed of rehydrated and ensiled corn grain, finely or coarsely ground, in substitution of dry corn grain, finely or coarsely ground.

2. Material and Methods

All procedures were approved by the Animal Use Ethics Committee (CEUA) under protocol number 029/2018.

2.1. Ensiling and processing

Shelled corn was purchased in the local market, with average vitreousness of 76%, determined by the method of Dombrink-Kurtzman and Bietz (1993)Dombrink-Kurtzman, M. A. and Bietz, J. A. 1993. Zein composition in hard and soft endosperm of maize. Cereal Chemistry 70:105-108., and dry matter (DM) content of 88%. Corn was ground in a hammer mill with 2-mm sieve for finely ground and 6-mm sieve for coarsely ground (Nogueira DPM 2 -7.5 HP, São João da Boa Vista, Brazil). Corn kernels were rehydrated with water, aiming to achieve 35% final moisture, and inoculated with microbial additive containing Lactobacillus plantarum MA 18/5U (3×1010 cfu/g) and Propionibacterium acidipropionici MA 26/4U (3×1010cfu/g) (Biomax Milho, Lallemand, Saint-Simon, France). After rehydration, the material was ensiled in lined trench silos, compacted with a tractor, aiming at a density of 1000 kg/m3 (Table 1), and sealed with polyethylene plastic film of 200 µm for 40 days. The dry corn finely and coarsely ground was stored in grain silos during the experiment.

Table 1
Density and percentage of dry matter (DM) of rehydrated corn grain silage finely ground (RCF) and rehydrated corn grain silage coarsely ground (RCC) at the silo opening

2.2. Experimental design, treatments, and feeding trial

Forty non-castrated young Angus crossbred bulls with average age of 13±1.4 months and average initial weight of 374±14 kg were used. All experimental animals were subjected to a 14-d adaptation period prior to the beginning of the experiment. All young bulls were previously fed corn silage on the farm of origin. Young bulls were transitioned to the finishing diet over a 14-d period following arrival, including starter Step-1 (fed d 1–7) and Step-2 (fed d 8–14).

The young bulls were blocked by weight and randomly assigned into four groups with five animals each in a 2 × 2 factorial scheme. Animals were housed in collective pens (two animals/pen), with 18 m2 total area with 8 m2 being covered. The factors evaluated were MPS (finely and coarsely ground) and two grain sources (dry ground corn and rehydrated corn grain silage). The treatments were diets containing dry corn grain, finely ground (DCF; 1.86 mm); dry corn grain, coarsely ground (DCC; 3.53 mm); rehydrated and ensiled corn grain, finely ground (RCF; 1.86 mm); and rehydrated and ensiled corn grain, coarsely ground (RCC; 3.53 mm).

Animals were fed twice a day (06.00 and 17.00 h), being offered 50% diet in the morning and 50% in the afternoon, allowing 5% of daily orts, ensuring ad libitum intake. The feed orts were quantified daily for the evaluation of DM (DMI) and nutrient intake by the animals, besides adjusting the diet to be provided.

The experimental period lasted 84 d, divided into three stages of 28 d. Animals were weighed for performance evaluation (ADG) at the beginning and end of each growth stage, after undergoing 12 h of solid fasting.

2.3. Laboratory analysis

The experimental diets were formulated according to the requirements estimated by NRC (2000)NRC - National Research Council. 2000. Nutrient requirements of beef cattle. Seventh Revised Edition: Update 2000. The National Academies Press, Washington, DC. https://doi.org/10.17226/9791
https://doi.org/10.17226/9791...
(Table 2). Weekly samples of each diet ingredients and orts were collected and frozen to form a composite sample per period. These samples were dried in a forced-air oven for 72 h at 55 °C and ground through a ١-mm mesh screen (Wiley mill, Arthur H. Thomas Co., Philadelphia, PA).

Table 2
Ingredients and nutrient composition of experimental diets with dry corn grain finely (DCF) or coarsely ground (DCC) and reconstituted corn grain silage finely ground (RCF) or reconstituted corn grain silage coarsely ground (RCC)

Subsamples were analyzed for DM and ash according to the Association of Official Analytical Chemists (AOAC, 2012AOAC International. 2012. Official methods of analysis. 19th ed. AOAC International, Arlington, VA.; methods 934.01 and 942.05, respectively). Crude protein (CP) was determined by Micro Kjeldahl steam distiller (AOAC, 2012AOAC International. 2012. Official methods of analysis. 19th ed. AOAC International, Arlington, VA.; method 984.13); diet neutral detergent fiber (NDF), acid detergent fiber (ADF), and lignin were analyzed with sodium sulfite and heat-stable α-amylase (Ankom A200I Fiber Analyzer, NKOM Technology, Macedon, NY, USA) according to Van Soest et al. (1991)Van Soest, P. J.; Robertson, J. B. and Lewis, B. A. 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74:3583-3597. https://doi.org/10.3168/jds.S0022-0302(91)78551-2
https://doi.org/10.3168/jds.S0022-0302(9...
; and starch content was determined by an enzymatic method (AOAC, 2012AOAC International. 2012. Official methods of analysis. 19th ed. AOAC International, Arlington, VA.; method 996.11).

Fecal grab samples were collected from each young bull twice at 08.00 and 20.00 h during the last 3 d of each period. Following the same processing and chemical evaluation procedures performed with the abovementioned samples. The total tract starch digestion (TTSD) was calculated according to Zinn et al. (2007)Zinn, R. A.; Barreras, A.; Corona, L.; Owens, F. N. and Ware, R. A. 2007. Starch digestion by feedlot cattle: Predictions from analysis of feed and fecal starch and nitrogen. Journal of Animal Science 85:1727-1730. https://doi.org/10.2527/jas.2006-556
https://doi.org/10.2527/jas.2006-556...
:

TTSD ( % ) = 99.9 [ 0.413 × F S ] [ 0.0131 × F S 2 ]

in which FS = fecal starch.

The metabolizable energy (ME) of the diet (Mcal/kg), also in samples of DCF, DCC, RCF, RCC, and whole corn plant silage, was estimated according to the equation proposed by NRC (2000)NRC - National Research Council. 2000. Nutrient requirements of beef cattle. Seventh Revised Edition: Update 2000. The National Academies Press, Washington, DC. https://doi.org/10.17226/9791
https://doi.org/10.17226/9791...
. From the derived estimates of net energy required for maintenance and gain, the NEm and NEg values of the diet were obtained using the quadratic formula proposed by Zinn and Shen (1998)Zinn, R. A. and Shen, Y. 1998. An evaluation of ruminally degradable intake protein and metabolizable amino acid requirements of feedlot calves. Journal of Animal Science 76:1280-1289. https://doi.org/10.2527/1998.7651280x
https://doi.org/10.2527/1998.7651280x...
.

x = ( b b 2 4 a c ) / 2 c

in which x = diet NEm (Mcal/kg); a = –0.41ME; b = 0.877ME + 0.41DMI + EG; c = –0.877DMI; and NEg = 0.877NEm – 0.41.

2.4. Statistical analyses

Statistical analyses were performed using PROC MIXED of SAS (Statistical Analysis System, version 9.3). Data were analyzed as a randomized block design using the following model:

Y i j k = μ + B i + P S j + S G k + P S j S G k + e i j k

in which μ = overall mean, Bi = random effect of block (i = 1 to 4), PSj = fixed effect of mean particle size (j = finely or coarsely ground), SGk = fixed effect of source grain (k = dry or rehydrated), PSjSGk = interaction between PS and SG, and eijk = residual error. When significance was observed, an F test was used to identify differences at P<0.10.

3. Results

In the present study, there were no interaction effects for parameters initial BW, final BW, ADG, feed efficiency, DMI, ADF intake, and ME of diets (Table 3). Statistical differences (P<0.01) were found for feed efficiency and DMI, when comparing diets containing dry ground corn and rehydrated corn grain silage, respectively. Diets with rehydrated and ensiled corn decreased the DMI (10.3%). Compared with diets containing dry corn, diets balanced with ensiled corn increased feed efficiency without affecting ADG.

Table 3
Effects of interactions of particle size (PART) and grain source (dry or rehydrated and ensiled) of corn on performance and nutrient intake

The NEm value of the diets was similar for rehydrated and dry corn treatments. However, the NEg for RCC increased values of the diet by 1.4% (RCF), 4.1%(DCF), and 10.9% (DCC).

For ADF intake, differences were found for the influence of MPS (P = 0.04) and grain source (P<0.01). There was a higher intake of ADF for animals fed dry corn and corn grain coarsely ground when compared with finely ground and rehydrated corn. In contrast, no significant differences (P = 0.48) were detected in ME intake when comparing grain source and particle size.

The ensiling process provided a 10.2% reduction in protein intake when compared with the use of ground corn, regardless of the particle size used. There was also an interaction effect of grain source on this trait showing higher protein intake in diets with dry corn over treatments with rehydrated corn, with no particle size effect.

Interaction effects between particle size and grain source were found for the variables daily intake of NEm, NEg, CP, NDF, and starch and for fecal starch and TTSD (Table 4). For variables CP and NDF (kg/d), higher intake values were found for animals fed dry corn in the diet.

Table 4
Effects of particle size (PART; finely or coarsely ground) and grain source (dry or rehydrated and ensiled) of corn on nutrient intake, fecal starch, and TTSD of cattle fed the evaluated diets

For starch intake (kg/day), differences were found between experimental diets, and there was influence of particle size (PART) and interactions for this parameter. Animals fed diets containing RCC had the lowest daily starch intake, being 4% lower than DCF.

Particle size and grain source effects were observed for fecal starch (P<0.01) and TTSD (P<0.01), with evidence that animals fed rehydrated corn diets showed greater efficiency on utilization of dietary starch. Our results about TTSD indicated that feeding beef cattle with rehydrated and ensiled corn increased total digestibility of corn starch. Animals fed RCF showed lower fecal starch losses of 37, 55, and 75% when compared with treatments RCC, DCF, and DCC, respectively.

4. Discussion

The decrease of DMI observed in diets with rehydrated and ensiled corn did not influence ADG. These results provided an increase of 13.3% in feed efficiency of animals fed rehydrated corn in replacement of dry corn. Similar to the results found in this trial, Jacovaci et al. (2021)Jacovaci, F. A.; Salvo, P. A. R.; Jobim, C. C. and Daniel, J. L. P. 2021. Effect of ensiling on the feeding value of flint corn grain for feedlot beef cattle: A meta-analysis. Revista Brasileira de Zootecnia 50:e20200111. https://doi.org/10.37496/rbz5020200111
https://doi.org/10.37496/rbz5020200111...
observed that the replacement of dry corn with rehydrated corn also did not affect the ADG, but there was a reduction in the DMI of 14.1% and an improvement in feed efficiency of 18.3%.

The inclusion of rehydrated and ensiled corn in diets for finishing cattle can increase feed efficiency by an average of 14% as a result of an average reduction of 12% in feed intake (Tonroy et al., 1974Tonroy, B. R.; Perry, T. W. and Beeson, W. M. 1974. Dry, ensiled high-moisture, ensiled reconstituted high-moisture and volatile fatty acid treated high moisture corn for growing-finishing beef cattle. Journal of Animal Science 39:931-936. https://doi.org/10.2527/jas1974.395931x
https://doi.org/10.2527/jas1974.395931x...
; Benton et al., 2005Benton, J. R.; Erickson, G. E.; Klopfenstein, T. J.; Macken, C. N. and Vander Pol, K. J. 2005. Effects of corn moisture and degradable intake protein concentration on finishing cattle performance. Nebraska Beef Cattle Reports. p.28-30.; Caetano et al., 2015Caetano, M.; Goulart, R. S.; Silva, S. L.; Drouillard, J. S.; Leme, P. R. and Lanna, D. P. D. 2015. Effect of flint corn processing method and roughage level on finishing performance of Nellore-based cattle. Journal of Animal Science 93:4023-4033. https://doi.org/10.2527/jas.2015-9051
https://doi.org/10.2527/jas.2015-9051...
; Caetano et al., 2019Caetano, M.; Goulart, R. S.; Rizzo, P. M.; Silva, S. L.; Drouillard, J. S.; Leme, P. R. and Lanna, D. P. D. 2019. Impact of flint corn processing method and dietary starch concentration on finishing performance of Nellore bulls. Animal Feed Science and Technology 251:166-175. https://doi.org/10.1016/j.anifeedsci.2019.03.006
https://doi.org/10.1016/j.anifeedsci.201...
; Paschoaloto et al., 2019Paschoaloto, J. R.; Guimarães, L. A.; Matos, E. M. A. and Villela, S. D. J. 2019. PSXII-22 Performance of Nellore bulls fed with rehydrated corn silage or rehydrated sorghum silage or sorghum grain in substitution of corn grain. Journal of Animal Science 97:419. https://doi.org/10.1093/jas/skz258.831
https://doi.org/10.1093/jas/skz258.831...
; Salvo et al., 2020Salvo, P. A. R.; Gritti, V. C.; Daniel, J. L. P.; Martins, L. S.; Lopes, F.; Santos, F. A. P. and Nussio, L. G. 2020. Fibrolytic enzymes improve the nutritive value of high-moisture corn for finishing bulls. Journal of Animal Science 98:skaa007. https://doi.org/10.1093/jas/skaa007
https://doi.org/10.1093/jas/skaa007...
). However, these benefits and results of using grain ensiling are based on major factors: moisture and nutritional content, particle size, quality of the ensiling process, and length of storage time (Owens et al., 1997Owens, F. N.; Secrist, D. S.; Hill, W. J. and Gill, D. R. 1997. The effect of grain source and grain processing on performance of feedlot cattle: a review. Journal of Animal Science 75:868-879. https://doi.org/10.2527/1997.753868x
https://doi.org/10.2527/1997.753868x...
; Rémond et al., 2004Rémond, D.; Cabrera-Estrada, J. I.; Champion, M.; Chauveau, B.; Coudure, R. and Poncet, C. 2004. Effect of corn particle size on site and extent of starch digestion in lactating dairy cows. Journal of Dairy Science 87:1389-1399. https://doi.org/10.3168/jds.S0022-0302(04)73288-9
https://doi.org/10.3168/jds.S0022-0302(0...
; Hoffman et al., 2011Hoffman, P. C.; Esser, N. M.; Shaver, R. D.; Coblentz, W. K.; Scott, M. P.; Bodnar, A. L.; Schmidt, R. J. and Charley, R. C. 2011. Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn. Journal of Dairy Science 94:2465-2474. https://doi.org/10.3168/jds.2010-3562
https://doi.org/10.3168/jds.2010-3562...
; Silva et al., 2018Silva, M. R. H.; Jobim, C. C.; Neumann, M. and Osmari, M. P. 2018. Corn grain processing improves chemical composition and fermentative profile of rehydrated silage. Acta Scientiarum. Animal Sciences 40:e42564. https://doi.org/10.4025/actascianimsci.v40i1.42564
https://doi.org/10.4025/actascianimsci.v...
; Gomes et al., 2020Gomes, A. L. M.; Bueno, A. V. I.; Jacovaci, F. A.; Donadel, G.; Ferraretto, L. F.; Nussio, L. G.; Jobim, C. C. and Daniel, J. L. P. 2020. Effects of processing, moisture, and storage length on the fermentation profile, particle size, and ruminal disappearance of reconstituted corn grain. Journal of Animal Science 98:skaa332. https://doi.org/10.1093/jas/skaa332
https://doi.org/10.1093/jas/skaa332...
; Salvo et al., 2020Salvo, P. A. R.; Gritti, V. C.; Daniel, J. L. P.; Martins, L. S.; Lopes, F.; Santos, F. A. P. and Nussio, L. G. 2020. Fibrolytic enzymes improve the nutritive value of high-moisture corn for finishing bulls. Journal of Animal Science 98:skaa007. https://doi.org/10.1093/jas/skaa007
https://doi.org/10.1093/jas/skaa007...
).

The action of proteolytic bacteria and kernel proteases break down the protein matrix during the storage period (Junges et al., 2017Junges, D.; Morais, G.; Spoto, M. H. F.; Santos, P. S.; Adesogan, A. T.; Nussio, L. G. and Daniel, J. L. P. 2017. Short communication: Influence of various proteolytic sources during fermentation of reconstituted corn grain silages. Journal of Dairy Science 100:9048-9051. https://doi.org/10.3168/jds.2017-12943
https://doi.org/10.3168/jds.2017-12943...
). Thus, there is an increase in the availability and digestibility of starch in both the rumen and the small intestine (Owens et al., 1986Owens, F. N.; Zinn, R. A. and Kim, Y. K. 1986. Limits to starch digestion in the ruminant small intestine. Journal of Animal Science 63:1634-1648. https://doi.org/10.2527/jas1986.6351634x
https://doi.org/10.2527/jas1986.6351634x...
; Owens et al., 1997Owens, F. N.; Secrist, D. S.; Hill, W. J. and Gill, D. R. 1997. The effect of grain source and grain processing on performance of feedlot cattle: a review. Journal of Animal Science 75:868-879. https://doi.org/10.2527/1997.753868x
https://doi.org/10.2527/1997.753868x...
; Hoffman et al., 2011Hoffman, P. C.; Esser, N. M.; Shaver, R. D.; Coblentz, W. K.; Scott, M. P.; Bodnar, A. L.; Schmidt, R. J. and Charley, R. C. 2011. Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn. Journal of Dairy Science 94:2465-2474. https://doi.org/10.3168/jds.2010-3562
https://doi.org/10.3168/jds.2010-3562...
).

The greater availability and fermentability of starch are associated with hypophagia (Oba and Allen, 2003Oba, M. and Allen, M. S. 2003. Effects of corn grain conservation method on feeding behavior and productivity of lactating dairy cows at two dietary starch concentrations. Journal of Dairy Science 86:174-183. https://doi.org/10.3168/jds.S0022-0302(03)73598-X
https://doi.org/10.3168/jds.S0022-0302(0...
). The explanation may be related to higher energy availability (NEm and NEg) and the “Hepatic Oxidation Theory”, defended by Allen et al. (2009)Allen, M. S.; Bradford, B. J. and Oba, M. 2009. BOARD-INVITED REVIEW: The hepatic oxidation theory of the control of feed intake and its application to ruminants. Journal of Animal Science 87:3317-3334. https://doi.org/10.2527/jas.2009-1779
https://doi.org/10.2527/jas.2009-1779...
. According to the authors, with higher starch fermentability, there is an increase in the production of short-chain fatty acids (SCFA) per unit of rumen-fermented organic matter, resulting in changes in the ruminal fermentation pattern, which leads to an increase in the molar proportion of propionate, which has a DMI suppression effect.

A potential explanation for increase in the production of SCFA is that the starch in corn experiences different degrees of exposure to enzymatic attack in the rumen (Beauchemin et al., 1994Beauchemin, K. A.; McAllister, T. A.; Dong, Y.; Farr, B. I. and Cheng, K. J. 1994. Effects of mastication on digestion of whole cereal grains by cattle. Journal of Animal Science 72:236-246. https://doi.org/10.2527/1994.721236x
https://doi.org/10.2527/1994.721236x...
; Huntington, 1997Huntington, G. B. 1997. Starch utilization by ruminants: from basics to the bunk. Journal of Animal Science 75:852-867. https://doi.org/10.2527/1997.753852x
https://doi.org/10.2527/1997.753852x...
), which indicates that rehydrated and ensiled corn is a more efficient processing method than grinding corn for beef cattle in feedlot.

The averages of NEg values of corn grain silage were markedly higher, 7% higher than dry flint corn (finely or coarsely ground). Ensiled corn in finishing diets increased starch and DM digestibility and had higher energy contents than diets based on dry corn. Previous studies have suggested that NEg of dry ground flint corn is lower than tabular values in nutritional models (e.g., NRC, 1996NRC - National Research Council. 1996. Nutrient requirements of beef cattle. 7th ed. The National Academies Press, Washington, DC.; NASEM, 2016NASEM - National Academies of Sciences, Engineering, and Medicine. 2016. Nutrient requirements of beef cattle. 8th ed. The National Academies Press, Washington, DC. https://doi.org/10.17226/19014
https://doi.org/10.17226/19014...
) and the ensiling corn grain may increase the NEg to 1.72 Mcal/kg DM (Zinn et al., 2011Zinn, R. A.; Barreras, A.; Corona, L.; Owens, F. N. and Plascencia, A. 2011. Comparative effects of processing methods on the feeding value of maize in feedlot cattle. Nutrition Research Reviews 24:183-190. https://doi.org/10.1017/S0954422411000096
https://doi.org/10.1017/S095442241100009...
).

The percentage of fecal starch was influenced by the treatments, in which the highest starch content in the feces was verified when the animals were fed dry corn ground to larger particles, demonstrating that when the corn was rehydrated and ensiled, it provided better utilization of this nutrient. Similar to the present study, Cozannet et al. (2018)Cozannet, P.; Lawlor, P. G.; Leterme, P.; Devillard, E.; Geraert, P. A.; Rouffineau, F. and Preynat, A. 2018. Reducing BW loss during lactation in sows: a meta-analysis on the use of a nonstarch polysaccharide-hydrolyzing enzyme supplement. Journal of Animal Science 96:2777-2788. https://doi.org/10.1093/jas/sky045
https://doi.org/10.1093/jas/sky045...
showed an increase in the energy of corn-based diets and a reduction in fecal starch content of bulls fed rehydrated and ensiled corn grain (Salvo et al., 2020Salvo, P. A. R.; Gritti, V. C.; Daniel, J. L. P.; Martins, L. S.; Lopes, F.; Santos, F. A. P. and Nussio, L. G. 2020. Fibrolytic enzymes improve the nutritive value of high-moisture corn for finishing bulls. Journal of Animal Science 98:skaa007. https://doi.org/10.1093/jas/skaa007
https://doi.org/10.1093/jas/skaa007...
).

In the same way, Ferraretto et al. (2015)Ferraretto, L. F.; Fredin, S. M. and Shaver, R. D. 2015. Influence of ensiling, exogenous protease addition, and bacterial inoculation on fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility in rehydrated and high-moisture corn. Journal of Dairy Science 98:7318-7327. https://doi.org/10.3168/jds.2015-9891
https://doi.org/10.3168/jds.2015-9891...
stated that the rehydration of ground corn increased starch digestibility, especially when ensiled, suggesting that these procedures may be viable alternatives under favorable climatic conditions for harvesting and storage. The increase in grain starch digestion was expected because according to Watson (1987)Watson, S. A. 1987. Structure and composition. p.53-82. In: Corn: Chemistry and technology. Watson, S. A. and Ramstad, P. A., eds. American Association of Cereal Chemists, St Paul, MN., the breakage of corneous endosperm occurs along the cell walls as a result of the strength of the protein matrix.

Another important point to highlight is that the finely ground dry corn grain also improved digestibility by decreasing fecal starch and increasing TTSD when compared with dry coarsely ground corn grain in the diet of young bulls finished in feedlot.

Starch digestibility is inversely proportional to the MPS for dry (Rémond et al., 2004Rémond, D.; Cabrera-Estrada, J. I.; Champion, M.; Chauveau, B.; Coudure, R. and Poncet, C. 2004. Effect of corn particle size on site and extent of starch digestion in lactating dairy cows. Journal of Dairy Science 87:1389-1399. https://doi.org/10.3168/jds.S0022-0302(04)73288-9
https://doi.org/10.3168/jds.S0022-0302(0...
) and rehydrated and high-moisture corn (Ferraretto et al., 2014Ferraretto, L. F.; Taysom, K.; Taysom, D. M.; Shaver, R. D. and Hoffman, P. C. 2014. Relationships between dry matter content, ensiling, ammonia-nitrogen, and ruminal in vitro starch digestibility in high-moisture corn samples. Journal of Dairy Science 97:3221-3227. https://doi.org/10.3168/jds.2013-7680
https://doi.org/10.3168/jds.2013-7680...
). In the present trial, a higher percentage of fecal starch was verified for the treatments that contained MPS of 3.53 mm. On the other hand, Gomes et al. (2020)Gomes, A. L. M.; Bueno, A. V. I.; Jacovaci, F. A.; Donadel, G.; Ferraretto, L. F.; Nussio, L. G.; Jobim, C. C. and Daniel, J. L. P. 2020. Effects of processing, moisture, and storage length on the fermentation profile, particle size, and ruminal disappearance of reconstituted corn grain. Journal of Animal Science 98:skaa332. https://doi.org/10.1093/jas/skaa332
https://doi.org/10.1093/jas/skaa332...
reported that flint corn presents divergent data when compared with dent corn.

The increase of TTSD observed in this trial may have occurred as a result of greater degradation of some zein protein in the starch-protein matrix of rehydrated and ensiled corn, improving greater solubilization of protein matrix and consequently, increasing starch granule surface area for bacterial attachment in the rumen (Huntington et al., 2006Huntington, G. B.; Harmon, D. L. and Richards, C. J. 2006. Sites, rates, and limits of starch digestion and glucose metabolism in growing cattle. Journal of Animal Science 84(suppl_13):E14-E24. https://doi.org/10.2527/2006.8413_supplE14x
https://doi.org/10.2527/2006.8413_supplE...
; Hoffman et al., 2011Hoffman, P. C.; Esser, N. M.; Shaver, R. D.; Coblentz, W. K.; Scott, M. P.; Bodnar, A. L.; Schmidt, R. J. and Charley, R. C. 2011. Influence of ensiling time and inoculation on alteration of the starch-protein matrix in high-moisture corn. Journal of Dairy Science 94:2465-2474. https://doi.org/10.3168/jds.2010-3562
https://doi.org/10.3168/jds.2010-3562...
; Ferraretto et al., 2015Ferraretto, L. F.; Fredin, S. M. and Shaver, R. D. 2015. Influence of ensiling, exogenous protease addition, and bacterial inoculation on fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility in rehydrated and high-moisture corn. Journal of Dairy Science 98:7318-7327. https://doi.org/10.3168/jds.2015-9891
https://doi.org/10.3168/jds.2015-9891...
).

Diets containing rehydrated and ensiled finely ground corn grain had higher NEg level accompanied by lower fecal starch loss. This may be an indication that the use in diets for finishing beef cattle requires supply adjustments, because although there may be a decrease in DMI, there was no influence on ADG.

5. Conclusions

Our results suggested that ensiled rehydrated corn grain improves feed efficiency, and the finely and coarsely ground rehydrated and ensiled corn grains increase the digestibility of starch in substitution of dry corn grain. The fine grinding of dry grain can also be a valid strategy in diet of finishing of young bulls in feedlot.

Acknowledgments

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance code 001.

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Publication Dates

  • Publication in this collection
    22 Aug 2022
  • Date of issue
    2022

History

  • Received
    6 July 2020
  • Accepted
    17 June 2022
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