EQUINE VETERINARY EDUCATION / AE / MARCH 2016


163


To mitigate the effect of OC on the equine industry,


several measures can be taken. Nutritionally, young horses should not be fed excessively and especially easily digestible carbohydrates should be avoided. This will reduce the chance of hormonal imbalances and may also reduce growth rate. It may be advisable to give supplemental copper (e.g. oral supplementation with copper sulfate equivalent to 0.5 mg Cu/kg live weight/day; Pearce et al. 1998) in late pregnancy in areas where the natural availability of copper is marginal to ensure high liver copper levels in the newborn foals. Foals should further be given sufficient pasture access, ideally all day long. Care should be taken that any changes in biomechanical loading of the vulnerable juvenile joints should be gradual and that high peak-loading (e.g. through inconsistent exercise opportunity or very rough terrain) should be avoided. As current management and breeding practices are


strongly implicated in the high incidence of OC in many breeds, some of them should be questioned. Do we really need to grow ever-taller horses where for millennia we were happy with much smaller ones? It is known, with the dog presumably as best example, that breeding to extremes will lead to severe health problems and thus generate serious welfare issues. In a performance animal such as the horse there is a kind of natural limitation to these excesses, but it is a moral obligation of the equine community not to go down that road and to balance the ambitions set by man with the health and well-being of the horse. Equine OC is to a certain extent inherent to the


species, as illustrated by the presence of the disorder in feral horses (Valentino et al. 1999), and will probably never be totally eliminated. The impact on economics of the equine industry and on the welfare of the horse can be considerably lessened by the judicious management of both breeding and a large number of environmental factors. There is a task for the equine veterinarian to increase public awareness of the many relevant factors that have been reviewed in this article and to influence decision-taking in the equine industry.


Authors’ declaration of interests No conflicts of interest have been declared.


Ethical animal research Ethical review not applicable for this review article.


Source of funding None.


Authorship


P. R. van Weeren wrote the draft; K. Olstad revised and amended the draft and provided a substantial number of figures and the video clips.


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