Acquired flexural deformation of the distal interphalangeal joint in foals

This study (originally prepared in Portuguese) concluded that a high incidence of acquired flexural limb deformities were as a direct result of the proximity to large wind turbines (2 MW) to the stud farm in question, where the vibration and noise caused by the turbines resulted in acquired flexural deformation of the distal interphalangeal joint in foals. The introduction and conclusions of the report are provided below in English. The full report, in English and Portuguese, can be downloaded from this page. 


In a Lusitano Stud Farm, near Lisbon, municipality of Torres Vedras, (hereinafter described as Stud), from 2008, was observed, the development of flexural deformities acquired in the equine forelimb. In all foals born after that date, there was a marked hyperflexion of the distal interphalangeal joint, occurring in the same sagittal plane (Figure 1). In some cases, the lesion was observed bilaterally, with a degree of alteration of the angle flexural variable. The Stud has existed since 2000 and prior to 2008, this symptom has not been observed in any horse, and there was no change in the diet (quality and quantity), the conditions of housing and exercise
regime to which the horses were be submitted. The pedigree of this horse stud also remained the same genetic lines from the top of it and some animals were introduced from different sources, both paternal and maternal that in the course of some months also exhibited the same sagittal deviation of the distal forelimbs, like other horses affected. The appearance of these lesions coincided with the installation of wind turbines (TE) 2 mega-watts that were implemented in the said land adjacent to the stud, which is the only environmental change that has occurred. 

The degree of hyperflexion of the distal interphalangeal joint, was observed as variable among foals. However, some have lost the ability to support almost the entire sole of the hoof on the ground, supporting only the clip, undermining its locomotion very significantly and, concomitantly, their well-being and quality of life. Associated with the onset of flexural deformation also appeared several behavioral changes in horses, passing these over time to sleep during the day and providing longer periods decubitus. 

The aim of this study was to evaluate the tissue damage present in affected animals, looking to estimate how far the stable environmental conditions may have interfered with the occurrence of acquired flexural deformation observed. 


The present study aimed at studying the acquired flexural deformities of the distal interphalangeal joint (DFAAID) foals on a stud farm which, in previous years, showed variations in their environmental conditions due to the installation of wind towers on adjacent land. 

The understanding of the pathogenesis of this condition would determine flexural to infer about the possible causes underlying the high incidence of DF observed in stud.

Once in the course of successive examinations to equine group, we excluded the existence of pain in primary forelimb that could lead to the shortening of the muscletendon of PRFD and the resulting DF, also considering that the pathogenesis of the process can be due to bone growth faster than the development of the tendon, the latter seems to be associated with the pathogenesis DFAAID observed in this group of animals.

Given the mechanical forces produced by wind turbines deployed on land adjacent to the stud, and we can not definitively conclude as to its responsibility in the process, one can not, however, rule out the influence of the low frequency noise and mechanical vibration may have had in the pathogenesis of DF verified. 

For proof, it would be necessary to have means that are outside the scope of this thesis. These means would require significant financial resources that allow creating an experimental environment in fully controlled conditions of vibration of air and soil that foals are subject to when they are born, by monitoring the changes of bone growth.

The fact that, in foal necropsied at seven months, there were several structural changes in tissues that contain cells rich in fibrillar skeleton (cardionector fabric, smooth and striated muscle), suggests that this issue of the influence of vibrations on cell growth should be targeted for further studies. 

The wind turbine bit is seen as harmful to the environment, with the Portuguese legislation only required environmental impact studies when the same park contains more than eight towers. 

However, should it prove in the future that their presence may have harmful effects, there will be more careful in preventing its installation in the vicinity of population or livestock.

In ignorance of these effects, and now under suspicion, it already seems sufficient reason for precautions are taken as to where the future will be authorized its installation. 

Flexural Deformation In Foals

Download file (1.88 MB) pdf

Source: https://www.repository.utl....

AUG 1 2012
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