INNOVATIVE HORSESHOEING WITH COPPER ALLOY

Dr. Mario N. ACUÑA Bravo M.V. Universidad de Chile Facultad de Ciencias Veterinarias y Pecuarias Área de Medicina y Cirugía de Equinos acunabravo@u.uchile.cl macuna@uchile.cl Making faith of the old expression "no hoof no horse" the horseshoeing is the best tool for the conservation of the hooves in horses that -domesticated by man- do some kind of activity for him. The horseshoeing of the hooves is carried out on a regular basis and is a process that must be performed by a qualified farrier and under the supervision of a veterinary specialist, in order to maintain a proper conformation and balance of the hooves, and enable it to develop the functions to which it is intended. The horseshoe is a piece of metal with semicircular shape which is attached to the hoof by means of nails. These may be of different materials, but the iron is used mainly to manufacture them, because is easy to find it in the market and its low cost. However, it has some disadvantages as the low attenuation of forces that arise from iron when impct against the ground, and can affect the integrity of the anatomical structures contained within the hoof and others at a higher level. However the undeniable protective effect of the horseshoe on the hoof, there is a series of drawbacks that may seriously affect the integrity of it and consequently the health and the life of the animal. Firstly, the attach of a structure such as the horseshoe, generates spaces absolutely inaccessible to the routines of cleaning that daily must be carried out in the hoof, then it tends to produce development of bacteria and fungi, which is favoured by the continuous contact with their faeces and urine, especially in those horses that remain long time in its stable or by environmental conditions of weather for those who remain in the open air. Added to the above is a wrong technique applied to the horseshoeing can lead to a bad conformation of the hoof and may be the cause for the presentation of various muscle-skeletal diseases that often become causes predisposing and determinants in shortening and/or cessation of competitive, recreational or occupational life of horses. In the present study in execution, it is discussed the two main facts of the problematic of the horseshoeing, the microbiological complications of its employment and factors related with the trauma that involves their use, especially when the technique of process is not done adequately in some aspects - by minimum that may be, in the trimming of the hoof or in the preparation and nailing of the horseshoe; all through the use of horseshoes made from an 83.5 % copper alloy. The encouraging results obtained - thus the microbiological problem first and the biomechanical effects after - are presented in this work as certified evidence of what

constitutes a technological innovation that will enable to improve the living conditions of the horses and to significantly prolong its recreational, sport and work use. A minimum retribution to everything that this noble specie has given during centuries to humanity. BACTERICIDAL AND FUNGICIDAL PROPERTIES In a study carried out with the Microbiology Laboratory of the Nutrition and Food Technology Institute of the University of Chile on the use of horseshoes made with a copper alloy (83.5 %) it was demonstrated that with them there is a drastic reduction of the problems of rottenness in the equine hooves, due a constant liberation of copper salts, which act on the aerobic and anaeróbic bacteria that colonize these structures, and in the same way on the fungi that contribute to the problem, and that as a whole generate a serious structural damage that often disables the equine to develop its habitual activity. This first phase of the project was an important part of the considerations by which the Agency of protection environment of the United States of N.A. (EPA), certified copper as the first bactericidal metal, in March 2008. With the objective of evaluating the antibacterial activity of horseshoes of copper alloy on the agents that cause pathologies in the hoof, were shod 40 horses of an equestrian center of the Chilean Army in the Metropolitan Region, 20 experimental shod with copper alloy and 20 controls with traditional iron horseshoes, the 40 animals were kept in equal conditions of accommodation, work and handling. There were identified and quantified qualitatively the presence of agents through aerobic and anaerobic samples taken on the sole of each hoof. In the group shod with copper alloy there was little microbial development, only two of 20 (10 %) had Klebsiella while in the control group (iron) was plentiful, 19 of 20 (95 %) showed presence of one or more Enterobacteriaceae, with E. coli and Proteus (60 % ). In the case of Bacillus sp was detected in the experimental group in nine of 20 (45 %) in little amount, while in the control group was isolated in 15 of 20 (75 %) with abundant development. S. aureus was only detected in the group with iron. With regard to the anaerobic C. novyi was detected in little amount in the experimental group while in the control group C. perfringens was detected in abundant quantity. B. gracilis was identified in both groups, with less development in the group with copper alloy. In terms of filamentous fungi and yeasts, the presence of filamentous fungi is demonstrated in regular amount in all samples from the control group (100 % ), on the other hand was detected less frequently, 13 of 20 (65 %) of horses shod with copper alloy; with regard to the yeast, these microorganisms were isolated only in the hooves of one of the horses shod with iron. As a practical effect on the use of copper alloy horseshoes it is noted a drastic reduction of bacteria and fungi, with a notable improvement in the structural condition of the hooves and the detention of the processes of putrefaction with its characteristic odor. However the immediate antimicrobial action that horseshoeing with copper alloy develops from the outset of its employment, considering the long time that the repair process of the hooves takes, the preventive use of this innovative fittings repair process is highly recommended. This part of the study was funded by Procobre Member Chile of the International Copper Association (ICA - New York), entity that promotes the use of copper in replacement of other materials through research studies that support and justify such action.

Photo # 1 Sample cultivation fitting helmet with copper alloy in half MYP for detection of Bacillus sp. (7 ds.)

Photo No. 2 Cultivation fitting helmet sample in half MYP iron for detecting Bacillus sp. (7 ds.)

Photo No. 3 Sample cultivation fitting helmet with copper alloy in half Baird Parker for detection of Staphylococcus sp. (7 ds.)

Photo No. 4 Growing sample iron hull fitting amid detection Baird Parker Staphylococcus sp. (7 ds.)

Photo # 5 Hoof severely affected by putrefaction in sole, frog and white.

Photo # 5 Horseshoes copper alloy.

Finally, and facing the possibility of an increase in serum levels of copper, and the toxicity that this could involve, it was made a determination of this element in each of the 40 horses that formed the study, they showed no difference in the content of copper, in horses shod with copper alloy and those shod with iron; serum copper averages, 97.5 and 97 ug/dl respectively, were obtained. GALVANIC CORROSION Whenever two or more not similar metals are immersed in a conductive environment as it is the water, or with high levels of this one, a chemical reaction takes place, establishing an electric current. The flow of the above mentioned electric current produces that the metal, chemically more active (softer), erodes. It has been shown that galvanic corrosion is a beneficial phenomenon in the use of copper alloy horseshoes, as favors and increases the release of salts of copper. It does not exist risk that this corrosion generates an enlargement of the orifices for the nails because the nails would have to remain for more than one year holding the horseshoes for the nail hole came to be bigger than the head of the nail and then allow that the horseshoe falls down. For the previous thing the fact is that being able to develop copper nails, it is preferred to maintain the use of conventional nails to make use of the charitable effect of the phenomenon of galvanic corrosion.

Photo No. 7 Abundant release of copper salts from the start of use of the horseshoe.

IMPACT ABSORBING PROPERTIES The use of copper (83.5%) alloy horseshoes significantly reduces the traumas that are generated after each impact of the horseshoeing against the ground. This is because the better elastic characteristics of copper and their alloys, with respect to the iron wich traditionally, horseshoes have been made. This feature of Copper alloys achieves that an important part of vibrations (energy of reaction) generated when the horseshoes impact against the ground, dissipate into the horseshoe and minimize the vibration that pass to the hoof and to other structures of the equine foot. This type of traumas are responsible for many non-recoverable injuries that results in the premature failure of many horses to continue developing their habitual activities. A study of "Comparative Analysis of the Behavior of Copper alloy and Iron Horseshoes" carried out with the Research and Testing of Materials Institute (IDIEM in spanish) of the Faculty of Physical and Mathematics Sciences, of the University of Chile, allowed to determine that the Copper alloy used in the development of this innovative horseshoeing has sufficient structural strength to withstand, first of all, the preparation process of the horseshoe (whether industrial or hand made process), then its adaptation to the hoof prior to its drive, and finally the repeated impact against the ground and the erosion resulting from its use for a 45 days period. In addition, a group of 12 sporting use horses from an equestrian center of the Chilean Army were horseshoed, six of them on its right hands and legs with copper alloy, and iron in hands and legs on the left side; the other six were horseshoed in the inverse way with copper in the left side and iron in the right side. Within 45 days of regular work with an average of 90 minutes of daily activity, the iron horseshoes showed an erosion average, by comparing the initial weight with the final weight, of 2.75% in hands and 6.09% in legs; for the alloy of copper horseshoes, these values were 6.71% and 10.33%, respectively. In the latter case, in the Copper alloy horseshoes, such wear did not affect the resistance of these and when removed they kept a proper structure to continue being used for another time. After their removal, all the horseshoes, copper alloy and iron made, were subjected to a macroscopic examination with a kit of three sprays for a structural study of metals (cleaner, liquid penetrator and revealing agent), not noting structural damage such as cracks or fissures to the inside of each horseshoe.

Photo Nº 8 Nails and horeshoes

With the Department of Mechanical Engineering, of the Faculty of Engineering of the University of Santiago, it was developed a computational model to determine the percentage of attenuation and transmission of impact. This study was conducted with the aim of determining the attenuation and transmission of forces that produces each horseshoe during the stance phase on the surface of the ground. To achieve this, the study focused on determining the trauma caused to the distal interphalangeal joint, in which it is included to capsule of the hoof and its internal anatomical structures, specially, the bone (distal sesamoids bones and third phalanx) and joints, since they are the structures that suffer major trauma in each impact.

Photo No. 9 Structural examination of the 48 cases studied horseshoes.

Photo No. 10 Kit three sprays. Cleaner (Crick 110), Penetrator (Crick 120) and Developer (Crick 130).

To perform this study, it was developed a mathematical model called "Impact Model " (Figure 4), based on the "Mass Spring Shock Absorber System", which later was implemented in the form of a 3D animation with the help of a computer program called “MSC. Visual Nastran 4 d ™ 4”, developing in the following way: it were considered three main components, the horseshoe (X0); the hoof (X1) and the rest of the horse mass (X2). Between X0 and X1, there were found two constants that correspond to the rigidity of the horseshoe (K1) and cushioning of the horseshoe (C1). Then, between X1 and X2, there were found two constants that belong to the rigidity of the hoof capsule and bone structures (K2) and cushioning of the capsule of the hoof and bony structures (C2). Each one of these components are united by means of springs and shock absorbers, transmitting forces from one element to another. These were quantified and thus it was found the comparative behavior in percentage form.

Before developing this computational study, it must be determined mechanical factors such as: elasticity module, restitution coefficient, and constants of softening and rigidity of the horseshoes, capsule of the hoof and bony structure s; and in addition, geometric factors such as: horse mass, weight of the capsule of the hoof with all their internal structures, weight of each horseshoe, and length and diameter of the hoof and the bones. The values of each of these constants (rigidity and softening) have been determined from the different mechanical factors, that were modified according to their geometry. After entering this data, it was made a fall of bodies over a totally rigid surface, and with this action it was intended to assess the response to the impact between the two horseshoes; for these studies it was considered the maximum time of support of the hoof on the ground. Then, once the computer program solved the mathematical equation of the "Mass Spring Shock Absorber System", the results of this impact were recorded in three graphs. The graph called "Contact Force Ground-Hoof", was developed in order to compare the percentage of impact strength between the two horseshoes. Then, it was developed another graph called "Horseshoe-Hoof Force", in order to compare the

Figure N º 1 Impact Model. (X0) Horseshoe; (X1) Hoof, (X2) horses remaining dough. (K1) constant rigidity of the shoe; (K2) constant rigidity of the capsule hoof and bone structures. (C1) damping coefficient of the horseshoe; (C2) damping coefficient of the hoof capsule and bone structures.

percentage of forces transmitted to the capsule of the hoof and bony structures, and the percentage of force tempered by each horseshoe in study. Finally, using a graph called "Hoof Force-Rest Horse Mass", it was compared the force that is transmitted to the rest of the horse mass, and that encompasses from the proximal interphalangeal articulation joint upwards. This study, is sought to quantify in a comparative way, the structural effect that produces the use of a horseshoe based on a Copper alloy compared with other iron-made, knowing the forces generated in both horseshoes under the same movement condition, and in this way show that the Copper alloy horseshoe, after impacting against the ground in support of each step transmits a minor amount of force to the structures, mainly bones and joints, contained inside and immediately over the hoof of horses.

Final Results: The results obtained refer the forces generated between each of the bodies; the first being those between the ground forces and horseshoe, the second between the horseshoe and the hoof, and the third between the hoof and the rest of the horse. It again shows that the models are applicable to both types of horseshoes, considering all boundary and initial conditions similar; the remaining variable is the mechanical composition of each horseshoe.

Figure2 - Percentage change in the interaction forces of the bodies

Table 1 shows the maximum values in each of the interactions of bodies (Tables remain in their original Spanish forms, y axis being percentage forces, x axis showing time in seconds)

Ground-Horseshoe

Horseshoe-Hoof Hoof-Horse mass

Maximum force Cu

91.44 91.46 91.47

Maximum force Fe

100 100 100

% Maximum force difference

8,56% 8,54% 8,53%

Conclusions: Given the results it is possible to obtain the following conclusions:

1. The copper horseshoe produces a force transmission of a lesser magnitude than that of the iron horseshoe according to the model.

2. There is a slight attenuation of the magnitude of the force as you progress through the union of elements.

3. The value of 8.75% attenuation at the peak level of force significant because the process is designed to model a cyclical action that may last a considerable time.

4. The interpretation of this result would mean that through the use of a copper based alloy in a horseshoe that reduces the initial and reactionary forces that one is preventing these forces from being felt by the horse.

5. Viewed from an energy standpoint, holding all other values constant, we find that a horse using copper based horseshoes uses less energy that one using an iron horseshoe.

6. Based on the previous conclusion, from a purely biomechanical point of view, reduced energy usage can lead to natural reserves being used to increase performance.

7. It should be noted that this is a simplified model based on a rigid surface cycle.

REFERENCES ARDILA, W; CHAVES, J; QUINTERO, E. Simulación de un sistema masa resorte amortiguador con circuitos electrónicos [paper]. Scientia Et Technica. 2009 Aug; 42(5): 220-225. BAXTER G.M. Adams and Stashak's Lameness in Horses. Ed. Wiley - Blackwell. 2011. BERRÍOS, A; MARTÍNEZ, R; PEREDO, A; BAEZA, E. Errores técnicos en el herraje de equinos fina sangre chilenos en la provincial de Ñuble, Chile. Avances en Ciencias Veterinarias. 1995; 10(1). CLAYTON, H. Ground Reaction Forces. The Dinamic Horse: A Biomechanical Guide to Equine Movement and Performance. Michigan, USA: Sport Horse Publications, 2004. p. 195-216. CODELCO.COM [Internet]. Chile: Codelco: Usos del cobre, Inc.; c2010-11 [actualizado el 12 de febrero del 2011]. Disponible en: http://www.codelco.com/cu_zonacobre/usos.asp IDIEM. Instituto De Investigación y Ensayo de Materiales. Universidad de Chile. Análisis Comparativo del Comportamiento de las Herraduras de Hierro y de aleación de Cobre, a través del ensayo de Impacto Charpy y del Desgaste Abrasivo. 2010. MARTÍNEZ, P; AZUAGA, M. Medición del modulo de elasticidad de Young [paper]. Laboratorio IV, Departamento de Física, UBA. 1997. RIVAS, P; ACUÑA, M; FIGUEROA, A; TRONCOSO, M; RUIZ, M; FIGUEROA, G. Estudio de la Actividad Antimicrobiana de Herraduras de Cobre en la Patología Infecciosa del Casco del Caballo. XXV Congreso Chileno de Microbiología, 2003 Nov 24-28, Antofagasta, Chile. THOMASON, J. Review of Some Past, Present and Possible Future Directions in Biomechanics of the Equine Hoof [paper]. IVIS. 2009.

PARTICIPATING ENTITIES

� UNIVERSIDAD DE CHILE

- Facultad de Ciencias Veterinarias y Pecuarias - Instituto de Nutrición y Tecnología de los Alimentos - Instituto de Investigación y Ensayo de Materiales (Facultad de Cs. Físicas y Matemáticas)

� EJÉRCITO DE CHILE (Escuela Militar y Regto. de Artillería Nº 1 “Tacna”) � UNIVERSIDAD DE SANTIAGO DE CHILE (Fac. de Ingeniería - Depto. de Ing. Mecánica) � PROCOBRE CHILE � CORPORACIÓN DE FOMENTO DE LA PRODUCCIÓN (Innova Chile) � KAWELL (Comercializadora KRAVIVA SpA)