Treatment of white line infections has traditionally been to remove the affected area of the white line and treat with some form of antimicrobial topical.Horse owner compliance at applying daily topicals to combat white line infections is reportedly short lived.  The effectiveness of daily topicals also comes into question once a horseshoe is applied to the hoof.  Traditional horseshoes made of steel and aluminum provide no antibacterial qualities. The application of copper-alloy horseshoes has been shown in studies to help with combating bacterial and fungal infections of the white line and eliminate the need for horse owners to apply daily topicals. 

The aim of this study was to use horses that have habitual white line infections and only apply copper-alloy horseshoes for the treatment of these issues, in order to see what qualitative difference can be observed over three (3), six ­­­(6) week trimming and shoeing cycles.  All the horses in the study are active riding horses (western, dressage and jumping).  There were no changes in riding, stalling or diet for any of the study horses.  Study horses were chosen for having habitual white line infection issues.  All horses before the study were being treated daily with a thrush medication and this practice was halted on day one of the study.  Horses were trimmed and shod by the same farrier students.  After each of the study horses’ feet were trimmed, photos were taken, and the foot were scored by the farrier student.  Each score was validated and documented by the author.  The amount of white line involvement was scored using a percentage of the total amount of white line infected.  For the seven horses used in the study, 26 feet were trimmed and shod, resulting in a reduction of infected white lines and significant overall improvement in the visual health of the white line.  Overall, twenty-one feet or 80.8% showed a visual improvement score by the end of the study.  Four feet or 15.4% showed no visual improvement score by the end of the study.  One foot or 3.8% showed a worse visual score by the end of the study.  The median white line involvement score decreased from 40-79% involvement in phase one to 10-39% involvement in phase three. 

It appears that the well-known and proven antimicrobial effects of copper-alloy do apply to the application of copper-alloy horseshoes in reducing the microbial damage to the horses’ white line.  Further benefit comes from the galvanic reaction that generates copper salts due to using a steel horseshoe nail in the copper-alloy horseshoe.

1. IntroductionHorse hoof needing copper alloy use

White line infections in horses is caused by opportunist fungi, bacteria, or a combination of both that break down and destroy the tissue connection within the hoof [1,2]. Treatment has traditionally been to remove the affected area of the white line and treat with some form of antimicrobial topical [3,4]. In personal conversations, equine professionals have stated that horse owner compliance at applying daily topicals to combat white line infections is short lived. The effectiveness of daily topicals also comes into question once a horseshoe is applied to the hoof. Traditional horseshoes made of steel and aluminum provide no antibacterial qualities [5,6]. The application of U.S. Environmental Protection Agency (EPA) [a] approved copper-alloy horseshoes have been shown in studies to help with combating bacterial and fungal infections of the white line and eliminate the need for horse owners to apply daily topicals [7,8].

Copper is man's oldest metal, dating back more than 10,000 years [6]. Its antimicrobial properties are becoming increasingly important to the prevention of infections [6,9]. Copper and copper alloys have been used for thousands of years to kill bacteria and can commonly be found in hospitals to minimize the spread of bacterial and fungal diseases [6,9,10].

The EPA has acknowledged and tested over 500 copper alloys. Copper is the only metal whose antimicrobial properties have been certified by the EPA [6,9,10]. Laboratory testing has shown that copper-alloy has continuous and ongoing antibacterial action killing greater than 99.9% of bacteria within 2 hours [9,10,11,12].

The only known EPA approved registration of copper-alloy horseshoes that could be found on the market is made ¬¬by the Kawell copper-alloyCopper Alloy Shoes horseshoe company¬¬ [b] (Figure 1) with Codelco copper [c] [13,14]. The aim of this study was to use horses who have habitual white line infections and only apply the Kawell copper-alloy horseshoes for the treatment of these issues, in order to see what qualitative difference can be observed over three (3), six ¬¬¬(6) week trimming and shoeing cycles. The results found that a significant amount of horses had a positive qualitative difference in the improvement of their white lines.

2.1 Materials and Methods

Study design Seven currently active riding horses (western, dressage and jumping) from the Meredith Manor International Equestrian Centre located in Waverly, WV [d] were used for the study. There were no changes in riding, stalling or diet for any of the study horses. Study horses were chosen for having habitual white line infection issues by the Meredith Manor farrier instructor. All horses before the study were being treated daily with a thrush medication and this practice was halted on day one of the study.

Horses were trimmed and shod by the same Meredith Manor farrier students. In phase one of the study, all seven horses had their steel shoes removed, trimmed, photos taken, data collected and shod with Kawell [a] copper-alloy horseshoes (test shoes) (Figure 1). Any modifications needing to be done were done following the manufacturers recommendations [15,16]. The manufacturer states that the shoes can be worked either cold or hot. When shaped cold, they should work like steel shoes, with a bit more spring when hit with the hammer. When shaped hot, they should be treated like aluminum and not heated more than 900 degreCopper Alloy Shoes from White Line Disease Studyes or they will fall apart [15,16].

In phase two of the study, all seven horses had the test shoes removed, trimmed, phohttps://admin-americanfarriers.epublishing.com/admin/article/duplicate?articleId=12437#tos taken, data collected and re-shod with the same test shoes. In the final phase of the study, phase three, all seven horses had the test shoes removed, trimmed, photos taken, and data collected.

2.2 Measurements

After each of the study horses’ foot were trimmed, photos were taken with an I-Phone 10 (Figure 2) and the feet were scored by the farrier student trimming the study horse by using the visual white line involvement form (Table 1).  Each score was validated and documented by the author.  The amount of white line involvement was scored using a percentage of the total amount of white line infected.  Due to the fact that copper-alloy leaches copper salts onto the foot and creates a discoloration (Figures 3 and 4), a pen nib (tip of a ball point pen) was used to probe the white line to confirm involvement of infected, seedy, non-firm white lines compared to uninfected firm white lines.

Table 1 – Visual White Line Involvement Form (check one box for the percentage infected)
Percentage Score Front Left Foot Front Right Foot Hind Left Foot Hind Right Foot
80 to 100%        
40 to 79%        
10 to 39%        
0 to 9%        
N/A        


2.3 Ethical ConsiderationsHorse hoof after copper alloy use

All the horses were owned by the Meredith Manor International Equestrian Centre and consent was given to use their horses in the study.  All horses were trimmed and shod by the Meredith Manor International Equestrian Centre farrier students and within their usual foot care standards.

2.4 Statistical Analysis

The data for phase one (beginning of study data) compared to phase three (end of study data) was examined using a one-way ANOVA, Minitab Descriptive Statistics and the Shapiro-Wilk test.

3. Results

For the seven horses, 26 feet trimmed and shod with the copper-alloy horseshoe, there was a significant improvement in the reduction of infected white lines.  Overall, 21 feet or 80.8% showed a visual improvement score by the end of the study.  Four feet or 15.4% showed no visual improvement score by the end of the study.  One foot or 3.8% showed a worse visual score by the end of the study (Table 2). 

Table 2: Kawell Copper-Alloy Horseshoe Visual Qualitative Measurement Scores
Date Horse Left Front Right Front Left Hind Right Hind
5/28/19 Ruger n/a n/a 80-100 10-39
7/8/19 Ruger n/a n/a 10-39 10-39
8/19/19 Ruger n/a n/a 10-39 0-9
5/28/19 Quest 80-100 80-100 10-39 40-79
7/8/19 Quest 1-39 40-79 10-39 40-79
8/19/19 Quest 10-39 10-39 0-9 10-39
5/28/19 Scottie 90-100 80-100 80-100 80-100
7/8/19 Scottie 10-39 40-79 40-79 40-79
8/19/19 Scottie 10-39 10-39 10-39 10-39
5/28/19 Juanita 80-100 10-39 40-79 10-39
7/8/19 Juanita 10-39 0-9 40-39 10-39
8/19/19 Juanita 10-39 0-9 1-39 0-9
5/28/19 Forman 10-39 10-39 80-100 10-39
7/8/19 Forman 0-9 10-39 10-39 10-39
8/19/19 Forman 0-9 10-39 10-39 0-9
5/28/19 Sugar 10-39 40-79 10-39 40-79
7/8/19 Sugar 0-9 10-39 10-39 80-100
8/19/19 Sugar 10-39 10-39 10-39 10-39
5/28/19 Ranger 80-100 10-39 0-9 80-100
7/8/19 Ranger 10-39 40-79 40-79 10-39
8/19/19 Ranger 0-9 10-39 10-39 10-39

The median white line involvement score decreased from 40-80% in phase one to 10-40% in phase three (Table 3, P value ‹0.005).

Table 3:  The Mean ±se white line involvement score following the use of the test shoe
Phase N Mean SE Mean St Dev Minimum Score Median Score Maximum Score
Phase 1 26  57.12 6.20 31.60 0-9 40-79 80-100
Phase 2 26   19.62 1.77 9.05 0-9 10-39 10-39

4. Discussion

This study presents evidence that the use of EPA approved copper-alloy horseshoes alone assists in the reduction of white line infection involvement in a high percentage of cases.  Treatment has traditionally been to remove the affected area of the white line and treat with some form of antimicrobial topical [3,4].  In this study, the use of the copper-alloy horseshoes was associated with significantly less white line pathology with no topicals having to be applied and no infected areas removed. 

The data suggests that if EPA approved copper-alloy horse shoes are used, there is no need for the horse owner to provide daily after-care of antimicrobial topicals as the horseshoe is continuously killing bacteria and fungus that come in contact with it thus providing an overall healthier foot.  Laboratory testing has shown that copper-alloy has continuous and ongoing antibacterial action killing greater than 99.9% of bacteria within 2 hours [9,10,11,12].  A second way bacteria is killed is through a process of a galvanic reaction between two dissimilar metals, the copper in the horseshoe and the steel nails.  This galvanic reaction generates copper salts that are leached out onto the sole of the hoof [17,18].  The leaching of copper salts makes an inhospitable environment for bacteria and fungi to live in [7,8,9,10].  Since application of antimicrobial topicals is not practical once covered by a horseshoe and its effectiveness comes into question, the ability to be able to apply and EPA approved copper-alloy horseshoe for providing long term proven.

5. Conclusion

It appears that the well known and proven antimicrobial effects of copper-alloy do apply to the application of copper-alloy horseshoes in reducing the microbial damage to the horses’ white line.  Further benefit comes from the galvanic reaction that generates copper salts due to using a steel horseshoe nail in the copper-alloy horseshoe.

6. Acknowledgements

The author would like to acknowledge the following people for their contribution to this study:  Meredith Manor International Equestrian Centre, Waverly, WV for the use of their facility and horses.  John Crothers, APF, CF Meredith Manor Farrier Instructor for assisting with conducting the study, arranging for farriery and organizing the horses to be tested in the study.  Richard Armentrout, APF-I, CJF-I for assisting the author in the study.  Farrier Students – Michael Baker, Amanda Brzesinski, Mason Cardwell, Michael Ferrier, Jeremy McKuster, Allison Pfeffer, Easton Timko, and Linsey Wrabel for providing all the farrier services and qualitative measurement assessments.  Kawell for providing all the necessary copper-alloy horseshoes for testing. 

7. Funding

Horseshoes for this study were provided by Kawell who played no role in the research. The author was reimbursed travel, hotel and food costs to and from the testing site. 

8. References

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