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EQUINE VETERINARY EDUCATION


Equine vet. Educ. (2020) 32 (11) 580-589 doi: 10.1111/eve.13073


Review Article Farriery for the foal: A review part 2: Therapeutic farriery


S. E. O’Grady* Virginia Therapeutic Farriery, Keswick, Virginia, USA *Corresponding author email: sogrady@look.net


Keywords: horse; foals; therapeutic farriery; hoof trimming; tendon laxity; flexural deformity; angular limb deformity


Summary The extensive nature of this topic warrants this review paper to be divided into two parts: ‘Basic trimming in foals’ and ‘Therapeutic farriery in foals’. Management of the feet and limbs during this juvenile period will often dictate the success of the foal as a sales yearling or mature sound athlete. Overall hoof care in the foal is often a joint venture between the veterinarian and the farrier. The orthopaedic disorders discussed in this paper that require input from the two professions are flexural limb deformities (FLD) and angular limb deformities (ALD). The concept of protecting the foot from the deleterious effects of mal-loading created by many FLDs and ALDs is just as important as using the symptomatology as an instrument to correct the deformity. This paper presents a review of the current information regarding the farriery for these two limb deformities while dispelling some of the anecdotal methodology, such as the use of toe extensions to treat flexural deformities, that presently exists. Considering the deficiency of information in the literature, segments of this text will be based on the author’s extensive clinical practice, comprehensive clinical records and comparisons of case outcomes.


Evaluation of the feet and limbs


The reader is referred to the section ‘Evaluating the foal’ in Farriery for the foal: A review part 1: Basic trimming (O’Grady 2020). The importance of evaluating limb conformation, early recognition of changes in flight pattern, limb placement and foot loading patterns cannot be over emphasised. It is also important to recognise changes in overall body condition or accompanying developmental disorders as these may occur prior to the onset of an angular limb deformity.


Flexural deformities


Flexural deformities have been traditionally referred to as ‘contracted tendons’. The primary defect is a shortening of the musculotendinous unit rather than a shortening of just the tendon portion, making ‘flexural deformity’ the preferred term (Adkins 2008; Hunt 2011;O’Grady 2012, 2014, 2017; Caldwell 2014, 2017). This shortening produces a functional length that is less than


necessary for normal axial alignment of the digit; this results in fixed flexion of the various joints of the distal limb especially the distal interphalangeal joint (DIPJ) (O’Grady 2012, 2017). Flexural deformities may be congenital or acquired. The


outcome and prognosis will vary with the severity and subsequent treatment of the flexural deformity.


Congenital flexural deformities Congenital flexural deformities are present at birth, may involve one or a combination of joints (e.g. carpal,


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metacarpophalangeal and distal interphalangeal joints) and are characterised by abnormal flexion of a given joint or all involved joints and the inability to extend the joint. Proposed aetiologies of congenital flexural deformities include mal- positioning of the fetus in utero, nutritional mismanagement of the mare during gestation, teratogens in various forages ingested by the mare and maternal exposure to influenza virus; it is also possible that the deformities could be genetic in origin (Hunt 2012; Caldwell 2014, 2017). Treatment of foals with a congenital flexural deformity varies with the severity and location of the deformity. It is not uncommon to see a foal born with a flexural deformity (generally bilateral) that involves a combination of joints in the forelimb such that the foal will stand and walk on the toe of the hoof capsule, is unable to place the heel on the ground and will assume a ‘ballerina’ stance with weight borne on the toes. A mild to moderate flexural deformity in which the foal can readily stand, nurse and ambulate is generally self-limiting and resolves with conservative treatment. Brief intervals of exercise for 1 h once or twice daily in a small paddock on firm footing for the first few days of life may be all that is necessary for the deformity to resolve. If the condition is unresponsive by the third day post-partum, i.v. administration of oxytetracycline (2–3 g), repeated every other day if necessary, is frequently beneficial (Madison et al. 1994; O’Grady 2012; Caldwell 2017). Although this treatment is in widespread use, caution must always be advised when administering this medication to a neonate. A variety of bandaging techniques and splints have been proposed, along with physical therapy to potentially stretch the involved soft tissue structures, thus possibly hastening recovery (Hunt 2011, 2012; Caldwell 2017). In the author’s opinion, the traditional use of a toe extension is not indicated, as applying a toe extension will generally result in the neonate becoming ‘clumsy’, stumbling and being unable to ambulate. The ‘lever arm’ principal of the toe extension to stretch the tendon is unrealistic and does not come without a price which is the likelihood of damage to the hoof capsule (O’Grady 2017). Foals with severe congenital flexural deformities of one


isolated joint or multiple joints present at birth that prevent the foal from standing and ambulating, require therapeutic intervention early in the clinical course of the case. Treatments include aggressive physical manipulation and stretching of the legs in conjunction with a variety of forms of external coaptation aimed at fatiguing the muscular section of the musculotendinous unit. Bandaging, transient static splinting with PVC bracing or dynamic splinting with an articulating brace, application of a flexible tension band along the dorsal aspect of the limb and casting are accepted techniques when properly applied and managed. Application of a cast in a mildly extended position shortly


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