Chronic Laminitis: Foot Management

The Welfare of Traveller and Gypsy Owned Horses in the UK and Ireland

Travellers and Gypsies are recognised ethnic groups in the UK and Ireland. Horse ownership is an important cultural tradition, however, practices associated with poor welfare are often perceived to be linked to these horse owning communities. Despite this, empirical studies on the welfare status of Traveller and Gypsy owned horses are lacking. To determine the welfare status of Traveller and Gypsy owned horses, 104 horses were assessed using a bespoke horse welfare protocol. This protocol assessed animal, resource and management-based measures. In addition, Qualitative Behaviour Assessment (QBA) identified horses’ emotional state. Results indicated that 81% of horses had an optimal body condition score, with no horse recorded as very thin/fat. The absence of limb conditions (95%), ocular (98%) and nasal (93%) discharges were evident in most horses, and 81% of horses responded positively to the voluntary animal approach test. The most commonly observed welfare issues were hoof neglect (27%), with hoof cracks/breakages (19%) being the most prevalent. QBA indicated that positive emotional states were more commonplace than negative. A relationship between QBA and other horse welfare measures was observed, e.g., improved mood was associated with better water availability. This research provides novel data in the under-researched area of the welfare of Traveller and Gypsy owned horses and counters perceptions of a poor welfare state in this group of horses.

Hoof kinetic patterns differ between sound and laminitic horses

BACKGROUND

No kinetic data on hoof loading in laminitic horses are available, despite their importance for optimising supportive shoeing therapies.

OBJECTIVES

To quantify the load distribution pattern in laminitic and sound horses.

STUDY DESIGN

Controlled observational study.

METHODS

Fifty-four sound and laminitic horses were assigned to three groups: control group (sound horses), group 1 (G1) horses with acute laminitis, evaluated immediately after acute clinical signs subsided, and group 2 (G2) horses that had been free of acute laminitis signs for 6-12 weeks. Measurements on both forelimbs in barefoot condition were performed during walk using the Hoof^™ System. Kinetic parameters were recorded and compared between hoof regions and groups using covariance analyses and t tests (P < .05).

RESULTS

Peak loading in the toe region occurred during midstance phase in control group, but during break-over in laminitic horses. This is reflected by the time to peak vertical force in the toe, which was significantly shorter in the control group compared to laminitic horses (G1 and G2) (76% ± 6% vs 89% ± 9 [P = .002], 86% ± 7 [P = .001] of stance duration respectively). The relative vertical force in the toe in the control group (46% ± 7%) was significantly higher compared to laminitic horses (G1: 29% ± 9% [P = .001]; G2: 32% ± 10% [P = .003]). The main shift of the load occurred between toe and middle hoof regions in laminitic horses as compared with the control group. No significant differences were found between G1 and G2.

MAIN LIMITATIONS

Measurements were not obtained in horses with acute laminitis on admission, to avoid risk of further damage to the lamellae.

CONCLUSIONS

Supportive therapy in laminitis should focus on supporting both caudal and middle hoof areas to decrease the peak pressure in these regions, and ease break-over during which the maximal loading of the toe occurs.

The Equine Hoof: Laminitis, Progenitor (Stem) Cells, and Therapy Development

The equine hoof capsule, composed of modified epidermis and dermis, is vital for protecting the third phalanx from forces of locomotion. There are descriptions of laminitis, defined as inflammation of sensitive hoof tissues but recognized as pathologic changes with or without inflammatory mediators, in the earliest records of domesticated horses. Laminitis can range from mild to serious, and signs can be acute, chronic, or transition from acute, severe inflammation to permanently abnormal tissue. Damage within the intricate dermal and epidermal connections of the primary and secondary lamellae is often associated with lifelong changes in hoof growth, repair, and conformation. Decades of research contribute to contemporary standards of care that include systemic and local therapies as well as mechanical hoof support. Despite this, consistent mechanisms to restore healthy tissue formation following a laminitic insult are lacking. Endogenous and exogenous progenitor cell contributions to healthy tissue formation is established for most tissues. There is comparably little information about equine hoof progenitor cells. Equine hoof anatomy, laminitis, and progenitor cells are covered in this review. The potential of progenitor cells to advance in vitro equine hoof tissue models and translate to clinical therapies may significantly improve prevention and treatment of a devastating condition that has afflicted equine companions throughout history.

Factors associated with prolonged treatment days, increased veterinary visits and complications in horses with subsolar abscesses

There is a lack of epidemiological studies about equine subsolar (hoof) abscesses even though they are among one of the most common causes of acute, severe lameness. The goals of this study were to (1) describe the equine subsolar abscess patient population of the University of Pennsylvania's New Bolton Center's Field Service and (2) to determine the factors that are associated with increased veterinary visits, prolonged treatment and complications. Descriptive statistics were performed on data collected from 160 cases of equine subsolar abscess. Inferential statistics were performed on a subset of those cases. No significant results were identified in relation to an increased number of veterinary visits. Poisson regression of days of treatment revealed that abscesses diagnosed in the summer (incidence rate ratio (IRR)=9.42, P<0.001) and abscesses found at the coronary band (IRR=3.21, P<0.001) were more likely to be treated for longer. Presence of a draining tract (IRR=0.73, P=0.017) and a higher lameness (IRR=0.30, P=0.01 for grade 3, IRR=0.1, P<0.001 for grades 4 and 5) score at presentation resulted in shortened treatment times. Abscesses affecting multiple portions of the digit were associated with an increased chance of complication. The study presented here is the first retrospective study on subsolar abscesses to the authors' knowledge.

Effect of hoof boots and toe-extension shoes on the forelimb kinetics of horses during walking

OBJECTIVE To determine and compare the effect of hoof boots (HBs) and shoes with a toe extension on stance duration, ground reaction force, and sole length in contact with the ground in nonlame horses during walking. ANIMALS 6 nonlame Standardbreds. PROCEDURES Force plate gait analyses of the forelimbs were performed while the horses were walking barefoot before manipulation of feet (baseline), while the horses were walking fitted with HBs, while the horses were walking shod with toe-extension shoes, and while the horses were walking barefoot after shoe removal. Horses underwent radiography of both forelimb feet to determine the sole length in contact with the ground when barefoot, wearing HBs, and shod with toe-extension shoes. Stance duration, ground reaction force, and sole length were compared among the various walking sessions. RESULTS Compared with baseline findings, stance duration increased significantly when horses were fitted with HBs (7%) or toe-extension shoes (5%). Peak forelimb ground reaction force was similar among walking sessions; however, time of braking force peak was significantly greater during the stance phase only when horses wore HBs. Also, the sole length in contact with the ground was significantly longer in horses fitted with HBs (14.3 cm) or shod with the toe-extension shoes (17.6 cm), compared with that for one of the barefoot hooves (12.7 cm). CONCLUSIONS AND CLINICAL RELEVANCE In nonlame horses, use of HBs prolonged the stance time and time of braking force peak, which is indicative of a slower deceleration phase during limb impact with the ground. Also, the use of HBs prolonged the deceleration phase of the stride and increased the sole length in contact with the ground.

Treating laminitis: beyond the mechanics of trimming and shoeing

Laminitis is typically classified into developmental or prodromal, acute, subacute, and chronic phases. Scientific evidence regarding the pathophysiology of laminitis does exist, but it is often conflicting and dependent on the clinician's interpretation/understanding of the study or the model used for inducing laminitis. The diagnosis of laminitis consists of obtaining an accurate history, performing a thorough physical examination, and taking good-quality radiographs. The use of radiographs for diagnosis and interpretation of laminitis is an absolute necessity for the clinician. Laminitis is one disease that requires the assembly of a team consisting of the veterinarian, the farrier, and the owner to be successfully treated.

Cellular and humoral immunity in chronic equine laminitis

Chronic equine laminitis causes persistent pain and lameness in affected animals and often necessitates euthanasia when pain management strategies become ineffective. Published studies as well as anecdotal reports suggest that this chronic inflammatory disease is associated with systemic alterations in immune responsiveness, perhaps involving an autoimmune component. We investigated this broad hypothesis by measuring a variety of immune indicators in healthy control horses (CON) and horses with chronic laminitis (LMN). We found that white blood cells from LMN horses produced more IFNγ than did cells from CON horses when stimulated in vitro with polyinosinic-polycytidylic acid [poly(I:C)], possibly due to an elevated number of circulating monocytes. No differences between groups were observed in plasma concentrations of IgG, IgA, IgM, IgE, or rheumatoid factor. Laminar tissue from LMN horses expressed elevated levels of keratinocyte damage-related genes as well as inflammatory cytokines and chemokines, which corresponded with a modest amount of neutrophil infiltration as shown by histological staining of fixed tissue and accumulation of neutrophil elastase protein. Taken together, our results do not support the hypothesis of an autoimmune component in chronic laminitis, although the strong induction of neutrophil chemokines and the presence of tissue neutrophils suggests that this cell type is likely involved in perpetuating the inflammation and tissue damage associated with this disease.