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Revista Ciencias Técnicas Agropecuarias

versión On-line ISSN 2071-0054

Rev Cie Téc Agr vol.30 no.4 San José de las Lajas oct.-dic. 2021  Epub 01-Dic-2021

 

ORIGINAL ARTICLE

Evaluation of Two Mills for Cattle Waste Grinding for Pig Feeding

MSc. Irania Quevedo HerreroI 
http://orcid.org/0000-0003-0027-6042

Dr.C. Pablo M. Hernández AlfonsoI 
http://orcid.org/0000-0001-9343-6919

MSc. Cristhian José CaricoII 

MSc. Vilma Toledo DiepaI 
http://orcid.org/0000-0002-7428-4283

Dr.C. Jorge García CoronadoI 
http://orcid.org/0000-0003-2936-2139

IUniversidad Agraria de La Habana, San José de las Lajas, Mayabeque, Cuba.

IIUniversidad Politécnica Tecnológica “José Antonio Anzoategui” (UPTJAA), El Tigre, Anzoátegui, Venezuela.

ABSTRACT

Pig production in Venezuela has been affected by the high costs of concentrated feed. An alternative to reduce production costs in feeding pigs is the use of cattle bones, due to their high protein content and other properties that lead to a good diet in the pig fattening process. The evaluation of the working organs of two mills in the crushing of cattle bones was carried out, determining the quality of crushing and energy consumption. The granulometry and impact energy on the Sharpy pendulum were determined. A 23 factorial type experimental design, dispersion curves and Pareto bars were applied. The controlled variables were type of mill, wet mass and type of bone and the response variables were sieved mass, grinding time, engine revolutions and humidity. The physical and mechanical properties as well as length, dry mass, wet mass, force and effort were determined. Finger and nose mills and hammer mills were compared for grinding quality and energy consumption. The hammer mill was found to have higher efficiency.

Keywords: Hammer Mill; Finger and Nose Mill; Sharpy Pendulum

INTRODUCTION

Pig feeding constitutes an extremely serious problem according to Campabadal (2009), taking into account that the pig performs an impeccable competition with man because its traditional diet consists of cereals and other products for human consumption and since its requirements of proteins are 5 to 8 times higher than those in man (Iglesias & Soto, 1987; Martinez, 2011). Due to the increase in food needs in the population in terms of eggs, meat and milk, it is desired that the nutrition of farm animals not only depend on plant sources but also on animal by-products (BPFA-ICA, 2020; FAO e IFIF, 2016; Keene et al., 2005; Uribe et al., 2011). Poultry and pig industries are the main consumers of meat and bone meal (Hamilton and Kirstein, 1996). To obtain a quality food, it is necessary to observe a series of zootechnical requirements that must be taken into account when submitting a material to the grinding process, mainly in relation to the size of the particle (Buitrago et al., 2004; Careeta, 2013; Covenin 1882-83: 83, 1983; Parra & Portilla, 1987). A feasible method for obtaining these flours is through the use of mills (Martínez, 2007; 2009; Paneque, 1988; Paneque et al., 2018). For this reason, the present work aims to evaluate the working regimes of hammer mills and fingers and nose mills during the obtaining of cattle bone meal of zootechnical quality for feeding pigs, with rational use of electrical energy.

MATERIALS AND METHODS

Two types of bones, scapula and femur, were selected as raw materials, since they meet the geometric conditions to guarantee their dimensioning more reliably and the hammer mill and the finger and nose mill were used (Chirino, 1980; Castillo, 2011). The bones came from two small meat industries in the area (Bodegón el Destete and Bodegón Doña África), located in the city of El Tigre, Anzoátegui State, Venezuela.

The physical and mechanical properties of the bones to be considered in the evaluation of the working organs of the mills were:

  • a.) Physical properties: humidity, mass, length, diameter and density.

  • b.) Mechanical properties: energy absorbed on impact (force and effort).

The grinding procedure was carried out in the Workshop of Warehouse 4, belonging to the UPTJAA's National Mechanics Training Program (PNF-Mechanics), which has an area of 1,500 m2, which is equipped with machines and equipment necessary for teaching.

In the tests carried out with scapula and femur bones, the experimental conditions were considered, taking different photographic images, with their respective dimensions in order to characterize:

  • a) Natural condition, in which the scapula bones are white, with solid shape and almost trapezoidal geometry and the femur bones are light white and with elongated hollow cylindrical shape and a soft moist mass inside.

  • b) Chopped condition (pieces of approximately between 10 and 12 cm).

  • c) Ground condition, to appreciate coloration and granulometry in bone meal (Ramos, 2010).

The DPM 4 hammer mill, manufactured in Brazil, is located in the Workshop of Warehouse 4, belonging to the UPTJAA National Mechanics Training Program. It is a stationary machine, used to grind mainly grains, activated by means of a three-phase electric motor that is turned on manually and has the following characteristics: power 8 kW, voltage 220 V, nominal current 15.7 A, nominal speed 3,300 rpm (rotation frequency), it has 24 hammers, drum diameter 0.293 m, drum length 0.095 m, hammer length 0.115 m, hammer width 0.042 m and hammer thickness 0.005 m. It should be noted that due to the lack of the original motor of this mill, it was worked with a 4 kW and 1 790 rpm motor.

The tool or working organ consists of a hammer (mobile) and blades (fixed), which act by impacting the raw material, successively cutting it into smaller pieces until the corresponding flour granulometry is obtained.

The CADELMA brand finger and nose mill, manufactured in Maracaibo, Venezuela, is located in the same place and is a stationary machine that is used to grind mainly grains. It is activated by means of a three-phase electric motor that is turned on manually by the operator and it has the following characteristics: power 4 kW, voltage 220 V, nominal current 15.7 A, nominal speed 1,790 rpm (rotation frequency), it presents 3 steel blades in the shape of hands 0.15 m high, 0.8 m wide and 0.01 m thick, drum diameter 0.34 m and drum length 0.14 m. The tool or working organ consists of paddles in the form of fingers and fixed blades that cut the material before crushing it.

Both mills work with a motor whose power is below the technical requirements established by the manufacturers (15 kW).

To obtain the flour from the selected raw material, the following steps were carried out:

  • Reception of the raw material: The used bones were minced in sizes of different measures (random) to be able to be processed by the mills.

  • Storage: The raw material was transported to Warehouse 4 belonging to the Department of Mechanical Engineering of the UPTJAA, where it was stored to later proceed to carry out the experiments.

  • Weighing and bagging in masses: The chopped bone pieces were weighed in mass samples of 1, 2, 3, 4 and 5 kg (three portions or samples for each kg of weighed mass respectively), being subsequently bagged.

  • Grinding: Once the distribution of the samples was completed (weighing and bagging), they were ground in both mills under the same weight and motor power conditions (4 kW) in the same weighing order.

  • Drying process: The ground bone samples were subjected to free or natural convection drying for a period of sixty-seven (67) days.

  • Sifting: After the drying process, the ground material was sifted through 4, 2 and 1 mm sieves.

RESULTS AND DISCUSSION

Analysis of the Physical-Mechanical Properties of Cattle Bones for their Crushing

Tables 1 and 2 show the measurements of mass, length, thickness and diameters of the bones of cattle scapulae and femur, with their respective averages; while Table 3 shows the function models: exponential, linear, logarithmic, polynomial order 2 and potential (Walpole et al., 1999; 2012).

TABLE 1 Scapula bone measurements 

Bone Sample Mass (g) Length (mm) Thickness (mm) Average (mm)
m L1 L2 e1 m L1
Scapula 1 730 370 400 17.3 10.9 5.2 385 11.1
2 750 350 390 19.9 9.8 4.6 370 11.4
3 750 370 395 19.7 13.9 6.8 382 13.5
4 780 370 380 19.0 13.5 7.2 375 13.2
5 1050 385 400 27.4 18.6 7.0 392 17.7
6 900 370 380 19.7 12.7 8.0 375 13.5
7 800 370 400 19.6 13.1 5.5 385 12.7
8 800 380 400 21.9 13.0 7.0 390 14.0
9 1180 380 420 24 16.6 9.4 400 16.7

TABLE 2 Measurements of the femur bones 

Bone Sample Mass (g) Length (mm) Diameter (mm) Average (mm)
m L1 L2 L3 D1 D2 D3 Length Diameter
Femur 1 1700 370 350 390 51,6 10.9 49.05 370 47.4
2 2070 350 380 410 56 9.8 51.2 396.7 50
3 2030 370 370 410 56.85 13.9 51.2 390 50.3
4 2070 370 340 400 58.2 13.5 52.9 366.7 51.5
5 1850 385 360 400 56.1 18.6 52.7 380 50.6
6 1970 370 340 390 19.7 12.7 52.9 363.3 52.1
7 1770 370 360 400 19.6 13.1 54.9 380 48.9
8 1850 380 350 380 21.9 13.0 55 363.3 49.4
9 2400 380 360 420 24 16.6 57.05 390 54.3

TABLE 3 Function Models, statistical requirement of correlation R2 

Models Bone-Requirements-Measurements
a) Scapula b) Femur
Features Length Thickness Length Diameter
R2 % R2 % R2 % R2 %
Exponential 0.4721 47.21 0.7541 75.41 0.2168 21.68 0.7726 77.26
Linear 0.4810 48.10 0.7762 77.62 0.2205 22.05 0.7776 77.76
Logarithmic 0.4600 46.00 0.7923 79.23 0.2163 21.63 0.7797 77.97
Polynomial of Order 2 0.5395 53.95 0.8128 81.28 0.2234 22.34 0.7786 77.86
Potential 0.4516 45.16 0.7780 77.80 0.2124 21.24 0.7720 77.20

According to the data obtained in Tables 1 and 2, it can be observed that, for the scapula bone, the thickness has better conditions regarding the position for the impact test on the Sharpy pendulum.

On the other hand, for the femur bone, the best position for the impact test is the diameter compared to the length in the Sharpy pendulum.

Analysis of the Operational Parameters Depending on the Quality of the Crushed

Table 4 shows the operational parameters of the finger, nose and hammer mills.

TABLE 4 Matrix of operational parameters of the finger and nose mill and hammer mill 

N° Tests Finger and nose mill Hammer mill
Initial mass (kg) Bone Milled time (s) Granulometries at 67 days Ground time (s) Granulometries at 67 days
1 mm 2 mm 4 mm 1 mm 2 mm 4 mm
1 1000 femur 120.23 0 0 100 60.15 0 50 200
2 1000 Scapula 120.5 0 50 50 45.65 25 100 300
1 2000 femur 180.49 0 50 150 60.57 50 150 400
2 2000 Scapula 240.12 50 100 400 60.2 50 150 500
1 3000 femur 300.42 0 50 200 120.46 50 200 500
2 3000 Scapula 360.47 100 200 700 120.42 100 200 700
1 4000 femur 480.36 50 200 600 120.5 50 250 800
2 4000 Scapula 540.18 100 300 900 120.59 150 400 1100
1 5000 femur 660.45 100 300 800 240.01 150 400 1200
2 5000 Scapula 900.12 150 400 1200 125.56 150 500 1500

Source. The authors

Figure 1 shows the measurements (length, thickness and diameter) against bone mass (scapula and femur). According to the data obtained in Figure 1, it can be observed that, for the scapula bone, the thickness has better conditions regarding the position for the impact test on the Sharpy pendulum. On the other hand, for the femur bone, the best position for the impact test is the diameter compared to the length in the Sharpy pendulum.

FIGURE 1 Measurements (length, thickness and diameter) against bone mass (scapula and femur). 

Figure 2 shows the behavior of the initial mass as a function of time of the finger and nose mill to determine the mass after the grinding and drying process.

FIGURE 2 Mass as a function of time of the finger and nose mill. 

Figure 3 shows the granulometric behavior of the femur and scapula bones, for the finger and nose mill after 67 days of free convection drying using 1, 2 and 4 mm sieves. It was observed that for the 1 mm and 2 mm sieves, the amount of mass was very low. However, using the 4 mm sieve, it was observed that for the scapula bone the amount of mass that passed through the sieve was greater than the amount of the femur bone mass that passed through it. Therefore, the scapula bone is better for sieving in this type of mill. Figure 3 shows the behavior of the initial mass as a function of the hammer mill time to determine the mass obtained after the grinding and drying process.

FIGURE 3 Initial mass as a function of hammer mill time (Table 4). 

Figure 3 shows the granulometric behavior of the femur and scapula bone for the hammer mill after 67 days of free convection drying using 1, 2 and 4 mm sieves. It was observed that for the 1 and 2 mm sieves, the amount of mass obtained was very low.

However, using the 4 mm sieve it was observed that for the scapula bone the amount of mass that passed through the 4 mm sieve was greater than the amount of mass of femur bone that passed through it. Therefore, the hammer mill also has a better response in crushing the scapula bone as a greater amount of final mass is obtained during sieving.

Considering the operational parameters of the mills (finger and nose and hammer mills), where both worked with a 4 kW motor, and according to Figures 2 and 3, it was observed that the hammer mill carried out the crushing process of the bones in less time and with a greater quantity of flour passed through the 4 mm sieve, the scapula bone being better.

Analysis of Operational Parameters Based on Energy Consumption

Table 5 establishes the operational parameters of the finger and nose mill and the hammer mill for determining energy consumption.

TABLE 5 Matrix of energy consumption parameters of the finger and nose mill and hammer mill 

Nº Tests Parameters for finger and nose mill Parameters for hammer mill
Bone Milled mass (kg) Intensity (A) Rotation frequency [rpm] Milled mass (kg) Intensity (A) [rpm]
Line 1 Line 2 Line 3 Engine Center Line 1 Line 2 Line 3 Engine Center
1 femur 750 14 16 15 1700 900 14.3 16 15 1775
2 Scapula 850 14.8 15.2 16.3 1796 800 13 15.4 14 1720
1 femur 1850 14.9 16.4 17 1700 1800 15 18 16 1782
2 Scapula 1750 14 16 15.9 1750 1700 14 16 15.9 1760
1 femur 2700 15.2 18 19.4 1720 2600 17.6 20.7 16 1749
2 Scapula 2600 18.4 19 21.2 1780 2550 16 21.8 19 1730
1 femur 3450 22.1 19.5 18 1740 3300 16.8 19.5 18 1780
2 Scapula 3650 15 18.5 22.2 1790 3700 15.3 17 16.4 1745
1 femur 4450 16.4 15.3 19.15 1760 4600 18.5 22.1 19 1765
2 Scapula 4500 16.8 17 19 1785 4400 16 17.4 14.2 1748

Source. The authors

Figure 4 shows the variation in intensity as a function of the mass processed for the finger and nose mill.

FIGURE 4 Graph of the final mass and intensity of the finger and nose mill (Table 5). 

It is observed in Figure 4 that for the finger and nose mill, the increase in intensity was reflected in line 1 and line 2, for the femur bone compared to the scapula bone. However, in line 3 the increase in intensity was present in the scapula bone compared to the femur bone, although this difference was not significant.

Figure 5 shows the variation of the intensity as a function of the mass processed for the hammer mill.

FIGURE 5 Mass as a function of intensity, hammer mill (Table 5

It is observed in the graph of Figure 5 that for the hammer mill the increase in intensity for line 1 was present with the femur bone with respect to the scapula bone. However, for line 3, the increase in intensity was reflected in the femur bone, compared to the scapula bone.

The comparison of the electrical consumption was determined with the finger and nose mills and the hammer mill in work operations of grinding the bones of the femur and scapula, since the motor source consumed electrical energy in a triphasic way (three lines of current). The behavior of this parameter is shown in Figures 4 and 5, indicating consumption decrease or increase in the crushing process as a function of time. As a result, the finger and nose mill consumed more electrical energy according to the increase in intensity since the contact between the grinding organ and the material required more grinding time because it was slower, making the grinding process slower.

Results of the Determination of the Theoretical (qt) and Real (qr) Productivity and the Efficiency (e) of the Hammer Mill and the Finger and Nose Mill

Hammer mill: Having the characteristics of this mill and using the equation represented in Table 6, the theoretical productivity of the hammer mill was obtained.

TABLE 6 Theoretical productivity of the hammer mill 

k Diameter, (m) Length, (m) ( bone density, (kg/m3) n, (rpm) qt, (kg/s) qt=k∙D2∙L∙(∙n/60
(2.2∙10-4) 0.293 0.095 1900 1790 0.092

From the data and the equation qr = m/t (amount of mass processed during machine work/clean work time), the real productivity (qr) was obtained, resulting in 0.028 kg / s for hammer mill. Substituting in the equation e = qr/qt, the efficiency of the hammer mill was obtained, resulting in 0.30 (30%).

Finger and nose mill: Having the characteristics of this mill and using the equation in Table 6, the theoretical productivity of the finger and nose mill was obtained, represented in Table 7.

TABLE 7 Theoretical productivity of the finger and nose mill 

k D,(m) L, (m) ( bone density (kg/m3) n, (rpm) qt, (kg/s)
(2.2∙10-4) 0.34 0.015 1900 1790 0.063

Using the same equation, the real productivity (qr) was obtained, resulting in 0.0076 kg/s, for the finger and nose mill. In the same way, the efficiency (e), of the finger and nose mill, was obtained, resulting in 0.12 (12%).

Determination of the Most Rational Variant of Bone Crushing Based on the Quality of the Crushing and Energy Consumption

Considering the operational parameters studied for finger and nose mill and hammer mill, when comparing the quality of crushing and their energy consumption, it was determined that the hammer mill has greater efficiency than the finger and nose mill (30% for the hammer mill and 12% for the finger and nose mills), in addition, the speed developed by the hammer mill during the milling process is higher than that of the finger and nose mills, which allows obtaining particles with a granulometry of the flour that meets the zootechnical requirement of pig feed. In reference to energy consumption, the finger and nose mill had higher consumption according to the increase in the intensity of the current, since the contact between the grinding organ and the material to be processed required more time in the grinding work, because it makes the crushing process slower and less efficient, due to its slower crushing speed.

CONCLUSIONS

  • In determining the physical-mechanical properties, it was observed that the scapula bone has greater hardness than that of the femur, so it requires greater effort during the grinding process, with the hammer mill behaving with better destructive capacity than the finger and nose mill.

  • The highest energy consumption was observed with the finger and nose mill, caused by the contact between the crushing organ and the processed bones, requiring a longer time in the grinding process, being less efficient and slower than the hammer mill.

  • The actual productivity of the hammer mill was higher than that of the finger and nose mill during the process of grinding of the scapula and femur bones, so to obtain bone meal the hammer mill was more efficient with a 30%.

  • The quality of the flour obtained from the zootechnical requirement established for feeding pigs with concentrated feed, better results were obtained with the hammer mill.

REFERENCES

BPFA-ICA: Buenas prácticas en la fabricación de alimentos para animales en Colombia, Instituto Colombiano Agropecuario, Grupo de Regulación Y Control de Alimentos para Animales, Bogotá D.C., Colombia, 2020. [ Links ]

BUITRAGO, G.V.; LÓPEZ, A.P.; CORONADO, A.P.; OSORNO, F.L.: ¨Determination of physical characteristics and mechanical properties of potatoes cultivated in Columbia¨, Revista Brasileira de Engenharia Agrícola e Ambiental, ISSN-1415-4366, 8(1): 102-110, 2004. [ Links ]

CAMPABADAL, C.: Guía técnica para alimentación de cerdos, 46pp., San José, Costa Rica, 2009. [ Links ]

CAREETA, R.: ¨Novel method to analyze post-yield mechanical properties at trabecular bone tissue level¨, Journal of the Mechanical Behavior of Biomedical Materials, 20(13), 2013. [ Links ]

CASTILLO, D.L.J.: Proyecto de factibilidad de la instalación de una planta procesadora de grasa animal y harina de carne y hueso para grupo El Tunal, Universidad Centro Occidental, Barquisimeto, Venezuela, 2011. [ Links ]

CHIRINO, L.: Proyecto de complejo mecanizado para la ceba de 45 mil cerdos en base a residuos alimenticios y diseño de una trituradora de martillos, Tesis (en opción al título de Ingeniero), Instituto Superior de Ciencias Agropecuarias de La Habana (ISCAH), San José de las Lajas, Habana, Cuba, 1980. [ Links ]

COVENIN 1882-83: 83: Alimento Complemento para Cerdos, Normas venezolanas, Caracas, Venezuela, 1983. [ Links ]

FAO E IFIF: Buenas prácticas para la industria de piensos-Implementación del Código de Prácticas Sobre Buena Alimentación Animal, Ed. FAO, Roma. Italia, 2016. [ Links ]

HAMILTON, R.; KIRSTEIN, D.: Harina de carne y hueso. Una fuente valiosa de nutrientes en las dietas de animales y aves de corral, Compañía de Litografia Kirbi, USA, 1996. [ Links ]

IGLESIAS, C.C.E.; SOTO, W.: Mecanización de los Procesos Pecuarios, Ed. Departamento de Ediciones del ISCAH, ENPES, San José de las Lajas, Habana, Cuba, 1987. [ Links ]

KEENE, B.; KNOWLTON, K.; WILSON, J.; MCGILLIARD, M.; HOLTAWAY, C.: ¨Bone breaking strength in mature dairy cows¨, Transactions of the ASAE, ISSN-2151-0032, e-ISSN: 2151-0040, 48(4): 1637-1643, 2005. [ Links ]

MARTÍNEZ, C.: Datos del molino de martillo para el análisis experimental, Universidad Central de las Villas (UCLV), Santa Clara, Villa Clara, Cuba, 2007. [ Links ]

MARTÍNEZ, C.: Libro de Instalaciones Agropecuarias, Ed. UCLV, Santa Clara, Villa Clara, Cuba, 2011. [ Links ]

MARTÍNEZ, J.: Diseño y Construcción de un prototipo de trituradora de desperdicios domésticos orgánicos, Tesis (en opción al título de Máster en Ciencias), Instituto Politécnico Nacional, México, 2009. [ Links ]

PANEQUE, R.P.: Transportadores en la Agricultura, Ed. Departamento de Ediciones del ISCAH, ENPES, primera ed. , pp. 276, San José de las Lajas, Habana, Cuba, 1988. [ Links ]

PANEQUE, R.P.; LÓPEZ, G.; MAYANS, P.; MUÑOZ, F.; GAYTÁN, J.G.; ROMANTCHIK, E.: Fundamentos Teóricos y Análisis de Máquinas Agrícolas, Ed. Universidad Autónoma Chapingo, primera edición ed. , vol. 1, pp. 456, ISBN-978-607-12-0532-2, Chapingo, Texcoco, México, 2018. [ Links ]

PARRA, M.; PORTILLA, D.: Estudio de las Propiedades mecánicas del sistema Óseo, Tesis (en opción al título de Ingeniero), Universidad Nacional de Colombia, Facultad de Ingeniería, Bogotá, Colombia, 1987. [ Links ]

RAMOS, C.N.F.: Aprovechamiento del desecho de huesos de res para la obtención de harina de hueso en la fábrica Federer, Tesis (en opción al título de Ingeniero), Escuela Politécnica Nacional, Quito, Ecuador, 2010. [ Links ]

URIBE, F.; ZULUAGA, A.F.; RODONI, L.M.; ANDERSON, E.; OCHOA, L.M.: Buenas prácticas ganaderas, Ed. Gef, Banco MundiaL, Fedegán, Cipav, Fondo Accion, TNC, ISBN-958-8498-36-8, 2011. [ Links ]

WALPOLE, R.E.; MYERS, R.H.; MYERS, S.L.: Probabilidad y estadística para ingenieros, Ed. Pearson educación, ISBN-970-17-0264-6, México D.F., 1999. [ Links ]

WALPOLE, R.E.; TEVES DE ALMEIDA, R.H.; MYERS, S.L.; YE, K.: Probabilidad y estadística para ingeniería y ciencias, Ed. Pearson educación, vol. 162, México D.F., 2012. [ Links ]

La mención de marcas comerciales de equipos, instrumentos o materiales específicos obedece a propósitos de identificación, no existiendo ningún compromiso promocional con relación a los mismos, ni por los autores ni por el editor.

Received: December 18, 2020; Accepted: September 20, 2021

*Author for correspondence: Irania Quevedo Herrero, e-mail: iraniaq@unah.edu.cu

Irania Quevedo-Herrero, Profesora Auxiliar, Universidad Agraria de La Habana, Facultad de Ciencias Técnicas, San José de las Lajas, Mayabeque, Cuba, e-mail: iraniaq@unah.edu.cu

Pablo M. Hernández-Alfonso, Profesor Titular, Universidad Agraria de La Habana, Facultad de Ciencias Técnicas, San José de las Lajas, Mayabeque, Cuba, e-mail: phernand@unah.edu.cu

Cristhian José Carico, Profesor, Universidad Politécnica Tecnológica “José Antonio Anzoategui”(UPTJAA), El Tigre, Anzoátegui, Venezuela, e-mail: cristhianjose@gmail.com

Vilma Toledo-Diepa, Profesora Auxiliar, Universidad Agraria de La Habana, Facultad de Ciencias Técnicas, San José de las Lajas, Mayabeque, Cuba, e-mail: vilma@unah.edu.cu

Jorge García-Coronado. Profesor Titular, Universidad Agraria de La Habana, Facultad de Ciencias Técnicas, San José de las Lajas, Mayabeque, Cuba, e-mail: jgarcia@unah.edu.cu

Los autores de este trabajo declaran no presentar conflicto de intereses.

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