“Equine Laminitis – Managing pasture to reduce the risk”  scritto da K.Watt (agronoma) è pubblicato on line dal governo australiano (Rural Industries and Development Corporation)

 Il pdf è scaricabile ed é possibile la lettura on line, dal sito di RIDC.

La laminite è il risultato del disordine metabolico indotto da una alimentazione inadeguata, adattata alle necessità di magazzino, facile distribuzione dei concentrati, pascolo in stagioni e di erbe non adatte, ignoranza. Il piccolo libro é una ottima introduzione al pascolo, le erbe, la fienagione ed a tutte le variabili che influenzano il contenuto di NSC (carboidrati non strutturali) che, ad alto indice glicemico dovrebbero essere ridotti e sotto controllo nella dieta.  La lettura dovrebbe essere integrata dagli articoli disponibili sul sito Safergrass di K.Watt. Lo stile è semplice e l’inglese di facile comprensione. I “fatti” consentono a chi  lo desidera di migliorare le proprie conoscenze e salvaguardare la salute del proprio cavallo. La naturalizzazione della gestione e lo spazio non debbono essere confusi con l’abbandono e la deresponsabilizzazione. Lo spazio, i campi, il pascolo vanno organizzati in modo tale da rendere la gestione economica e sicura al tempo.

Watt- Equine lamitis…pasture

Understanding Winter Laminitis

L’estate é appena iniziata allontanando in alcune regioni il pericolo insito nel pascolo primaverile. Mentre questo nemico deve essere sempre mantenuto a debita distanza é il momento di focalizzare l’attenzione su un avversario più insidioso, il freddo inverno. Quando si pensa alla laminite appaiono campi di erba fresca e lussureggiante, sacchi di mangimi e granaglie, infezioni. L’inverno porta con se altri motivi di pericolo da sommare ai soliti, simili a quelli della primavera e da ricercarsi nelle ghiande ed altri frutti stagionali. Il danno al tessuto laminare è lo stesso come la manifestazione del male é simile.

When you think of laminitis you probably picture fat ponies on lush spring pastures, horses that broke into a grain supply, or even a disastrous complication of Potomac Horse Fever or Strangles infection. However, every winter some owners and caretakers are faced with the onset of obvious foot pain in their horses for no apparent reason. What’s going on?
The first thing to do is rule out foot pain from unforgiving ground conditions, rather than from laminitis. All horses have difficulty negotiating uneven frozen ground and their frogs and soles can become bruised. If this is the issue, all of the horses will be affected to similar extents. They will be obviously more comfortable, if not normal, in their stalls, on mats, even on a smooth barn aisle.
The horses with true winter laminar pain will also be more comfortable off uneven frozen ground, but remain obviously lame. The lameness often appears suddenly and can be quite severe.
These horses often have a history of prior laminitis problems, or at least a suspicion of insulin resistance/equine metabolic syndrome. Some even have a history of winter laminitis that strikes the same time every year and is resistant to all efforts at treatment until one day in early Spring it suddenly goes away.
Questo caso é particolarmente diffuso, si tratta di animali che sperimentano diversi livelli e periodi di zoppia solitamente attribuiti fantasiosamente alle più svariate cause, prima fra tutte la sobattitura tanto di scarso interesse quanto rara nel cavallo scalzo e opportunamente pareggiato.
I have been working closely with insulin resistant horses for over 10 years. Winter laminitis pain is a significant problem for some of these horses. Many have a history of laminitis at other times of the year, but some do not. Many questions need to be answered, but significant headway has been made in understanding and controlling this issue.
L’insulino resistenza e la sindrome metabolica sono concetti applicati ai cavalli negli ultimi anni, del terzo millennio. Spesso utilizzati a sproposito (sovradiagnosticati) forniscono una entrata sicura a professionisti.
Il primo intervento in ogni caso é la modifica della dieta da riportare a quella che sarebbe propria di ogni cavallo. Scarsi zuccheri prontamente utilizzabili, dieta bilanciata.

Horses that have undergone bouts of laminitis in the past can have damage to the vascular supply to their feet. When exposed to the cold, the normal regulatory mechanisms that guarantee no areas of the foot are deprived of sufficient circulation for dangerous periods on cold exposure may fail.
Lo zoccolo del cavallo come l’epidermide di ogni mammifero compreso l’uomo, é provvisto di sistemi di by-pass arterovenosi che vengono chiamate anastomosi. Il sangue non raggiunge la rete capillare se questi by-pass sono aperti. Mentre il normale funzionamento è utile al controllo della perfusione e allo scambio termico l’impropria apertura priva le zone a valle di ossigeno e nutrienti.
Even when there have not been previous obvious laminitic episodes, high levels of cortisol in Cushing’s horses and insulin resistance in metabolic syndrome horses may put these animals at risk of cold induced pain. Cortisol has been documented to dramatically increase hoof responses to vasoconstrictors, circulating chemicals that make vessels contract. Insulin is normally a vasodilator, an agent that makes blood vessels dilate. With insulin resistance, this response may be blocked.
Il livello di ormoni circolanti é sottoposto a variazione ed andamento periodico sia giornaliero che stagionale. Questo influenza direttamente l’insorgenza della patologia e rende più elaborato il sistema di analisi e utile il prelievo durante le varie stagioni.
In short, the normal reaction of the horse’s body to decrease blood supply to the distal extremities and hooves during cold exposure may cause decreased blood supply to the hoof sufficient enough to cause pain. In a normal horse, vessels constrict in response to cold but will periodically open up again to increase blood supply if oxygen tension gets too low. If the vascular network is damaged, or if constriction is higher than normal because of hormonal issues, this might not occur.
La vasocostrizione generalmente ha effetto anestetizzante a seconda delle modalità e tempi, come ben succede nella ferratura . Una situazione prolungata e particolarmente aggressiva non può altro che causare solo danni maggiormente evidenti.
Evidence supporting this theory was obtained by an owner of a horse with a history of repeated bouts of winter laminitis. She took her horse to her veterinarian’s clinic for thermographic examination. Thermography measures the surface temperature of the body. The horse was placed in a room with an air temperature of 40° Fahrenheit/4.4° centigrade. After removing leg wraps and lined hoof boots, the temperature of the front feet, which had been repeatedly affected by laminitis in the past, dropped considerably lower than the temperature of the hind feet.
Protection against the cold is therefore the first step in combating winter related hoof pain. Horses should be protected from high winds and rain/snow, blanketed, wear leg wraps to warm the lower legs and boots, preferably lined. Effective lower leg wraps include standard polos and cottons, leg warmers or even fleece lined shipping boots.
Questo può sembrare astruso a tutti coloro che pensano alla laminite = piede caldo. In effetti il piede caldo ed infiammato a causa della dieta non ha nulla a che fare con questo dolore determinato da problemi di circolo che a loro volta causano un danno al tessuto laminare. Da notare però che facilmente il danno vascolare primitivo è di origine alimentare e da ricercare in altri attacchi di laminite “convenzionale” precedenti, primaverili o meno.
This helps, but for some horses is not enough. Since they are metabolically and endocrinologically challenged, responses to the challenge of cold weather could be playing a role here.
We know that thyroid hormone activity is increased in cold weather. This causes energy generation in the cells to become less efficient so that more energy is wasted as heat rather than going to energy generation. It has also been reported by researchers that insulin levels become highly variable in cold weather.
In other species, adaptation to cold weather includes decreased metabolic rate and induction of insulin resistance.
Mi muovo di meno, ho meno necessità e trasformo tutto quello che posso in grassi di riserva. E forse vado in letargo.
None of these changes cause problems for normal horses but horses with metabolic and endocrine problems may be pushed over the edge. When blanketing and wrapping is not enough to prevent hoof pain, supplementing with a combination of an adaptogen and L-arginine is usually very supportive.
An adaptogen is an herb that supports healthy stress responses. Jiaogulan is a good one to use because it also strongly supports vascular nitric oxide production which supports blood delivery to the extremities and feet. However, it is not a particularly strong adaptogen. Some horses respond better to stronger adaptogens also safe for IR horses such as North American Ginseng, Eleutherococcus, Rhodiola and Schizandra. Jiaogulan can be given twice daily, the others once daily.
La Rhodiola, specificamente, come l’Arginina si trova facilmente in farmacia e dovrebbe essere utilizzata a dosi pertinenti adattandole al peso dell’animale. Gli adattogeni hanno la virtù di essere maggiormente efficienti quanto più la situazione lo richiede e di rimanere silenti in caso contrario.
L-arginine can be given at least twice daily, sometimes 3 to 4 times daily, to support blood levels. L-arginine is an amino acid that can be utilized to make nitric oxide. Alternatively, L-arginine-alphaketoglutarate (AAKG) may be used. This form of arginine seems to have a more prolonged effect.
In summary, winter laminitis predominantly strikes horses with metabolic issues, with or without a prior history of laminitis. It appears to be caused by both reduced circulation to the feet in cold weather and the effects of cold stress. Steps to consider taking are:
-Make sure Cushing’s Disease, if present, is well controlled by sufficient pergolide and that the horse is on an appropriate low sugar and starch diet Protect from severe and wet weather by adequate shelter.
-Use blankets, leg wraps and lined boots.
-Supplement with an adaptogen and L-arginine to combat stressresponses and support circulation
Il Cushing’s è un evento possibile. E’ il caso soprattutto di cavalli anziani. Può essere con sicurezza diagnosticato tramite analisi di laboratorio e pertinente lettura. Porta con se segni che ne facilitano l’identificazione.
Molti cavalli non necessitano di essere trattati con la Pergolide farmaco che ha dimostrato pesanti effetti collaterali in medicina umana tanto da essere escluso dal mercato . Gli ormoni sono farmaci difficili da utilizzare con parsimonia e consapevolezza. Assai spesso la sola dieta ferrea, comunque da adottare in ogni caso, è sufficiente al controllo della malattia insieme alla gestione protetta.
Degenerazione, sindrome metabolica, insulino resistenza ed altri malanni trovano come comune denominatore di attacco la DIETA ed il MOVIMENTO. I mali degenerativi si possono rendere meno invalidanti e gli altri, che non dovrebbero essere considerati malattia ma manifestazione di disagio causato dalla mancato rispetto delle necessità di specie, si possono prevenire.
Il pareggio adeguato dello zoccolo ed in particolare l’angolo di finitura della parete riveste anch’esso un ruolo preventivo chiave. La minore sollecitazione del tessuto laminare da parte del terreno di appoggio fa si che a parità di altre condizioni il danno risulti inferiore ed il recupero della condizione accelerato.

Eleanor Kellon, VMD. Note in italiano di Franco Belmonte, biologo.

Journal of Equine Veterinary Science –
Clinical Outcome of 14 Obese, Laminitic Horses Managed with the Same Rehabilitation Protocol (In Press)

www.hoofrehab.com/WhatsNew.html (link alla pagina di Pete Ramey)
www.sciencedirect.com/science/article/pii/S0737080613006370 (link diretto)

Questa documentazione di esperienza clinica espone, nello stile richiesto dalla comunità scientifica, quanto fatto da almeno 10 anni sul campo dai pareggiatori, “hoof care provider”, sia di Pete Ramey che di Jaime Jackson e da Jackson da più tempo ancora secondo protocolli diversi nella forma ma simili nella sostanza soprattutto per quanto riguarda la gestione, alimentazione, movimento controllato, protezione con accessori non permanentemente fissati allo zoccolo. Un successo senza pari. Qui i risultati sono documentati e elaborati statisticamente ai fini della pubblicazione del lavoro reso possibile dalla collaborazione tra la American Hoof Association e la Auburn University.

I principi sono espressi nel “Hoof Rehabilitation Protocol” della American Hoof Association di cui faccio parte come Member e Certified Trimmer. Lo trovate qui nel sito nella sezione AHA.

La metodica alla Auburn University é stata arricchita, per alcuni cavalli, con trattamenti farmacologici di sostegno che di sostegno appunto sono, acceleratori accettabili, condivisibili per il controllo del dolore, a seconda della circostanza e spesso non determinanti come l’esperienza precedente, più asciutta, sia mia che di Jaime Jackson e di altri, oltre naturalmente a quella di Pete Ramey, dimostra.

Trovate due casi di laminite cronica particolarmente indicativi risolti in tempi brevi nel periodo di una ricrescita dello zoccolo, sulla pagina “studio di zoccoli” di questo sito:
Cercate Brigitte e Asini Laminitici.
In questi due casi ho seguito lo stesso protocollo di riabilitazione.

Se volete un commento e una esposizione della tecnica impiegata da Taylor-Ramey e una panoramica di quanto é possibile fare e ottenere comunque senza l’ausilio della diagnostica per immagini sono disposto a raggiungervi nella sede che riterremo più opportuna.

Dr. Franco Belmonte
Biologo, AHACT

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Clinical Outcome of 14 Obese, Laminitic Horses Managed with the Same Rehabilitation Protocol

Debra Taylor DVM, MS,
Alex Sperandeo, John Schumacher DVM, MS,
Thomas Passler DVM, PhD,
AnneWooldridge DVM, PhD,
Rhodes Bell DVM,
Adam Cooner DVM,
Leah Guidry BS,
Hannah Matz-Creel DVM,
Ivy Ramey,
Pete Ramey

ABSTRACT

A specific method of rehabilitation was used to manage obese horses with laminitis, and clinical outcome was evaluated after 5 to 20 months. Clinical data from 14 similar laminitis cases were statistically analyzed to evaluate response to rehabilitation. Data were analyzed using repeated measures or logistic regression methodologies. Each horse presented as obese and laminitic with no history of a systemic inflammatory disease. The rehabilitation method emphasized a mineral-balanced, low nonstructural carbohydrate diet; daily exercise; hoof trimming that minimized hoof wall loading; and sole protection in the form of rubber hoof boots and/or hoof casts. Distal phalanx alignment within the hoof capsule was significantly improved, and hoof wall thickness was significantly decreased (P <.0001) following treatment. Solar depth was significantly increased (P < .0015). Reduction of palmar angle measurements was detected in acutely and chronically affected horses. This treatment effect was statistically greater for horses with chronic laminitis than for horses with acute laminitis (P interaction < .0001). Horses were 5.5 times more likely to be sound post-treatment than before treatment. Daily exercise, dietary modification, and removal of ground reaction force from the hoof wall were foci of the rehabilitation program. Hoof care and husbandry as applied to these horses may be an effective method of rehabilitation of horses from obesity-associated laminitis.

1. Introduction

It is generally accepted that prognosis for laminitic horses with significant palmar rotation of the distal phalanx is guarded to poor [1]. Other indicators predicting outcome of laminitic horses include severity of lameness [2], white blood cell count [3], weight of the horse [4], number of feet involved [5], and the magnitude of the corrected (for magnification) distance between the proximal aspect of the extensor process of the third phalanx and the most proximal extent of the proximodorsal wall measured on a lateromedial radiograph [6]. The inciting cause of laminitis may also be a factor in outcome. Recent studies indicate that the basement membrane of epidermal laminae of ponies with insulin-induced laminitis remains intact [7] and minimal upregulation of matrix metalloproteases occurs in the laminae when laminitis is insulin induced [8]. Preservation of the basement membrane in these laminitic ponies suggests that some horses with endocrinopathic laminitis mayhave complete or at least improved hoof repair once the ongoing insulin-induced laminar insult is eliminated.

Results of studies indicate that exercise and controlled feed intake decrease insulin resistance in ponies [9-11]. However, exercising laminitic horses is controversial when movement causes pain and/or may further damage inflamed lamina.

The goal of this study was to evaluate the outcome of laminitic horses subjected to a specific management program that emphasized a mineral-balanced, low nonstructural carbohydrate diet; daily exercise; hoof trimming that minimized hoof wall loading and reestablished a lower palmar angle; and sole protection in the form of rubber hoof boots and/or hoof casts (see sections 2.3 to 2.7 below) when needed for horse comfort and safety. This program was expected to improve foot morphology, radiographic parameters, and gait. The medical records of 14 obese, laminitic horses that participated in the management program were examined, and objective parameters were statistically analyzed.

2. Materials and Methods

2.1. Case Selection

The medical records of 14, obese (body condition score >6), laminitic horses that had acutely or insidiously developed bilateral forelimb (13 horses) or bilateral forelimb and hindlimb (1 horse) lameness with clinical and radiographic signs of laminitis were evaluated. A horse’s medical record was included for evaluation if the horse had a history of each of the following: development of laminitis while on grass pasture, a presenting Obel lameness score >=2 [12] (subjectively determined by D.R.T.), radiographic evidence of palmar rotation of the distal phalanx or proximal rotation of the hoof capsule of both forelimbs, a presenting body condition score >6, and management with the protocol described below. Horses that had either divergent growth rings of the hoof capsule or remodelling of the distal phalanx, or both, were classified as having “chronic” laminitis, and those who lacked divergent growth rings of the hoof capsule and had no evidence of remodelling of the distal phalanx at the time of presentation were considered to have acute laminitis. “Lipping” of the distal phalanx on the lateral radiograph was considered evidence of remodelling. Growth rings that were wider in the heel region than in the toe region were considered divergent. Statistical analysis was performed using clinical data at 2 time points: initial presentation and when the client requested the final radiographic reevaluation and the horse had returned to its previous level of soundness (5-12 months postinitial presentation).

2.2. Radiographs and Measurements

All lateromedial radiographs of the front feet were acquired by the same clinician (D.R.T.) [13], using criteria described by Redden [14,15], and included the following recommended standards: a true lateral projection with the primary beam striking the foot in a horizontal plane 1 cm above the bearing surface; a zero subject-to-film distance by ensuring that the medial aspect of the hoof was in contact with the radiographic cassette and maintaining a consistent distance between the radiograph machine and the cassette; detailing the face of the hoof wall with barium; and having the horse standing on 2 wireembedded positioning blocks of equal height, with the limbs in a vertical position. The proximal aspect of the hoof capsule and dorsal margin of the hoof capsule in all cases had been marked with barium paste to bisect the foot from the roots of the most distal hairs of the coronary band to the tip of the hoof capsule at the bearing surface. The sagittal plane of the sole of the hoof was marked with barium on some horses.

Five radiographic parameters were measured and recorded for statistical analysis (Fig. 1A, B): (1) The thicknesses of the dorsal horn and lamellar tissues were measured proximally at the level of the base of the extensor process and distally at the level of the tip of the distal phalanx (or just proximal to “lipping” if present).

Fig. 1. (A) Method used to measure the degree of rotation (yellow angle) and the palmar angle (black angle), which were evaluated before and after treatment on both front feet of each horse. (B) The red line shows the measurement of the horizontal distance from the coronary band to the extensor process (CE); the green line shows sole depth measurement (SD), and the blue lines show measurement locations of the thickness of the proximal and distal aspects of the dorsal hoof wall (H:L zones). Each of these measurements was evaluated before and after treatment on both front feet of each horse.

These proximal and distal measurements of dorsal hoof wall thickness were made on lines drawn perpendicular from the dorsal cortex of the distal phalanx to the edge of the barium marker that had been applied to the dorsal hoof wall. The numerical difference between the proximal and distal measurements (distal measurement – proximal measurement ¼ numerical difference between thickness of proximal and distal dorsal hoof wall) was used for statistical analysis purposes as an indicator of the relationship of the dorsal hoof wall to the dorsal cortex of the distal phalanx. (2) Solar depth was measured on a perpendicular line drawn distally from the tip of the third phalanx to the outer border of the sole or the proximal margin of the barium column (if the mean sagittal plane of the sole had been outlined with barium). (3) The palmar angle was measured as the angle of incidence between the solar margin of the distal phalanx and the bearing surface. (4) The vertical distance from the horizontal plane through the proximal extent of the hoof capsule to the most proximal aspect of the extensor process of the distal phalanx was measured and described as the coronary band: extensor process distance [15], previously designated the founder distance [6]. (5) The degrees of rotation between the dorsal hoof wall and the dorsal cortex of the distal phalanx were measured.

Raw radiographic measurements were used for statistical analysis without correction for innate magnification because a zero subject-to-film distance was always used, and absolute numbers were compared only to previous radiographic measurements determined for the same horse.

2.3. Management Protocol: Hoof Care

The hooves of all horses were routinely trimmed (every 3 or every 6 weeks by P.R. or A.S.). The basic concept of the trim strategy was to eliminate weight bearing by the hoof walls by promoting weight bearing by the sole, bars, and heel buttress and to prevent increasing elevation of the palmar angle created by excessive heel growth relative to toe growth. The length of the trim cycle, 3 versus 6 weeks, was based on each horse’s current heel-to-toe hoof growth pattern. Heels were lowered during each trim based on the following parameter: the heel plane was lowered to 0.25 inch above the live sole without removing more than 10 mm of heel at any one trim. Therefore, horses that were growing much more hoofwall in the heel region than in the toe region required a 3-week trim cycle during the first few months of treatment. The trim cycle was lengthened to 6 weeks as soon as the heel-to-toe hoof growth ratio had equalized sufficiently so that the heel height did not vary by more than 10 mm during that time period [16].

Fig. 2. (A) The basic shape of the trim is shown. Note the hoof wall is trimmed to the level of the sole plane and then bevelled to minimize weight bearing by the hoof wall at the toe and through the quarters. (B, C) Hooves from 2 different horses are shown during a routine trim. Note that a heel plane is being established by the rasp on each hoof. This plane is approximately 2° to 3° away from the palmar angle (solar plane of the distal phalanx).

At the time of each trim, the hoof walls were trimmed to a length level with the sole and then bevelled to minimize weight bearing by the hoof walls (Fig. 2A). Thin soles were protected as described below to maximize horse comfort and safety. Hoof wall flares were not rasped on the outer surface of the hoof until the new growth of the hoof wall had grown at least two-thirds of the distance from the hairline to the ground. During each trim, a heel plane that was approximately 2° to 3° degrees positive to the palmar angle and 0.25 inch above the live sole plane was established (Fig. 2B).

After trimming so that the sole, rather than the wall, bore weight, solar pressure was minimized by using one or more of the following methods of solar protection: (a) application of removable strap-on hoof boots1,2 (Fig. 3) with foam rubber pads1,3 and/or dental impression material4,5; (b) application of hoof casts6 to cover pads1,3 and/or dental impression material4,5 that had been applied to fill the solar concavity and collateral sulci; (c) application of glue-on hoof boots1 with dental impression material4,5 filling the solar concavity and collateral sulci; or (d) allowing the horse to go barefoot on yielding terrain including soft ground free of rocks or loose beds of pea gravel (5- to 8-mm-diameter stones) 10 cm deep.

Fig. 3. Two styles of protective hoof boots1,2 used to protect and hold soft protective pads1,3 in place on the feet of the horses of this

Removable, strap-on hoof boots1,2 with pads1,3 were always the first choice as an initial method of solar protection and were used as needed for horse comfort and safety on the available terrain. Horses wore hoof boots nearly 24 hours per day until their use no longer improved the level of horse comfort. Horse comfort was subjectively judged based on the Obel lameness scale and the horse’s daily habits of self- initiated movement and recumbency. Owners were instructed to remove the strap-on hoof boots with pads from the hooves briefly each day to allow cleaning and drying of the hoof and the boot. During the later stages of treatment (when the horse had 2-3 cm of uniform new hoof growth from the coronary band), removable hoof boots (used as a method of solar protection) were, for some horses, replaced by hoof casts or glueon hoof boots (for periods of 6-12 weeks). The decision to use hoof casts or glue-on hoof boots (in lieu of removable strap-on boots) was based on one of following factors: the owner’s inability to maintain the removable strap-on hoof boots or the need for establishment of a shallow (5- to 6-mm) air space under a very thin sole (ie, <7 mm) or a solar perforation or defect. Hoof casts were always chosen over glue-on boots when the need to establish and secure pads with cutout air spaces under jeopardized sole regions arose. The use of deep pea gravel footing for horses with sole depths of 8 to 10 mm or more was encouraged. It was noted that rock diameter needed to be matched to sole depth in order to observe signs of increased comfort. Use of pea gravel footing was recommended only for periods of rehabilitation process when the current sole depth and pea gravel diameter combination allowed horses to exhibit signs of increased comfort while on the gravel. Signs of increased comfort included (1) the horse choosing to stand in the gravel rather than other terrain, (2) the horse turning more easily in the gravel, (3) the horse spending more time standing while on the gravel (as opposed to other available terrain), and (4) the horse assuming a more normal stance when standing on the gravel. Barefoot turnout was not allowed until a horse had sole depth >=12 mm and was able to move comfortably on the current terrain without hoof protection.

2.4. Management Protocol: Diet

The weight loss goal was to decrease each horse’s body condition score to a five [18]. Dietary restrictions recommended for each laminitic horse included elimination of grains and/or processed feeds, elimination of fruits, vegetables, and other sweet or starchy treats, partial or complete restriction from pasture grazing (this restriction varied according body condition of the horse and size or condition of available pasture). Horses were fed Bermuda grass hay ad libitum. During the initial weight loss period, owners were advised to have their hay tested for nutrient content. Advice was also offered at the onset of treatment that any untested hay be soaked inwater prior to feeding in effort to minimize the chance of feeding high nonstructural carbohydrate hay. Retrospectively, none of the owners reported having tested the types of hay fed to these 14 horses. Owners reported soaking their hay in water for various time periods ranging from 30 minutes to 12 hours prior to feeding. Mineral supplementation was provided empirically to balance suspected nutritional content of local hay/ grass to meet recommendations of the National Research Council [17].

2.5. Management Protocol: Exercise

Turnout in a grass-free paddock or daily in-hand exercise was encouraged after the following (1) hooves had been trimmed to minimizeweight bearing by the hoofwall; the desired heel plane and palmar angle (<= 10 degrees) had been established by trimming; and when the hooves had been protected by soft protective hoof boots with pads (as described in Section 2.3) that provided enough comfort for the horse to have a heel-first hoof landing. In-hand exercise was increased daily by adding 5- to 10-minute increments to each exercise session until horses were walking 30 to 45 minutes 2 or 3 times daily. Owners were instructed to observe for the intended heel-first impact of the hoof boot and to walk the horse only while the hoof boots were securely in place. They were instructed not to walk the horse if the hoof impact appeared to be toe-first and to discontinue daily walking (and call the veterinary/ hoof care provider team) if the horse seemed to have increasing pain after walking.

2.6. Management Protocol: Medication

Phenylbutazone (4.4 mg/kg once every 24 hours or 2.2 mg/kg once every 12 hours orally) was used for ameliorating pain when needed to maintain an Obel grade score <=2. Acepromazine (20 mg every 8 hours intramuscular) was administered to 6 horses as a peripheral vasodilator during the initial 2 to 4 weeks of therapy. The soles of horses with solar necrosis and prolapsed solar corium (5 horses) were treated with topical tetracycline and/or metronidazole. One horse with solar necrosis received intravenous oxytetracycline (7 mg/kg every 12 hours intravenously for 14 days). During periods of active abscess formation and/or drainage of exudates from the sole, owners were advised to soak the feet 3 to 5 times weekly in either magnesium sulfate solution or 50% acetic acid solution.

2.7. Body Condition Scoring

The body condition scores of horses were determined by D.R.T., using the system described by Henneke [18] before treatment and at the endpoint radiographic examination after the owners reported a return to the prelaminitis level of soundness.

2.8. Statistical Analysis

Response variables, including coronary band-toextensor process distance, palmar angle, degree of rotation, sole depth, and difference of the dorsal hoof wall thickness at the proximal and distal aspects, were measured or scored before and after treatment, hence the data had the character of repeated measures, ie, multiple observations on the same experimental unit. Data were analyzed using repeated measures methodology as implemented in SAS(R) PROC GLIMMIX.7 To account for the possibility of an interaction, data were analyzed using repeated measures methodology using a linear model in which the main effects condition (condition refers to chronicity (acute or chronic) of laminitis) and treatment as well as their interaction were included. Inspection of studentized residuals (¼ standardized residuals distributed as a t random variable) indicated that the normally assumption was warranted for all response variables, except OBEL. The interaction was significant only for palmar angle (P ¼ 0.002). Because all other response variables had a nonsignificant interaction term (P >= 0.63) it was dropped from the model resulting in a main effects model. Significance of pairwise differences was calculated using the PDIFF or SLICEDIFF option of the LSMEANS statement in the above named PROC. The dichotomous OBEL before and after treatment scores were analyzed using logistic regression as implemented in in SAS(R) PROC LOGISTIC. Means and 95% confidence intervals on the logit scale were back-transformed to frequencies.

2.9. Long-term Follow-up Owner Survey

Owners of 12 horses were contacted 23 to 73 months after initial onset and asked the following questions: “Has the horse had any foot pain due to laminitis relapses or hoof abscesses since the follow-up radiographic exam?” and “Is your horse currently considered rideable?”

3. Results

Six different breeds were represented within this group of horses (7 Tennessee Walking Horses, 2 Appaloosa, 2 Quarter Horses, 1 grade horse, 1 Rocky Mountain Saddle Horse, and 1 Peruvian Paso; 10 geldings and 4 mares, ranging in age from 4-22 years; mean age, 13 years). Descriptive information for the measurements taken at pre- and post-treatment examinations is given in Table 1. At initial examinations, the median Obel lameness score for all pretreatment laminitic horses was 3.5 (range: 0.5-4). In contrast, at post-treatment evaluations, 12 horses appeared subjectively to be sound at a trot or equivalent gait, and the median Obel lameness score for all horses was 0 (range: 0- 1). All owners considered the quality of their horse’s gait to be equivalent to their prelaminitic gait. One of the authors (D.R.T.) evaluated the gaits of all horses at the time of endpoint radiographic examination and subjectively scored 12 horses (0 of 10) and 2 horses appeared mildly lame at a trot (2 of 10). Statistically, horses were 5.5 times more likely to be sound at post-treatment examination than at pre-treatment examinations. A statistically significant decrease of the third phalanx rotation was detected posttreatment (P < .0001, 95% CI for differences: 3.8°-6.5°). The differences of the dorsal hoofwall thicknesses between the proximal and distal aspects of the distal phalanx was significantly reduced at post-treatment evaluation (P < .0001, 95% CI for differences: 2.0-3.5 mm). The reduction of the coronary band-to-extensor process distance was not statistically significant (P ¼.10, 95% CI for differences: -0.2- 2.3 mm). Solar depth was significantly increased at posttreatment evaluation (P ¼ .0015, 95% CI for differences: 3.1-5.4 mm). An overall reduction of palmar angle measurements was detected in acutely and chronically affected horses. This treatment effect was statistically greater for horses with chronic laminitis than for horses with acute laminitis (P interaction < .0001).

A decrease of the body condition scores of each horse was observed during the treatment period, and while the median body condition score was 8.5 at initial evaluation, a median body condition score of 5 was observed at posttreatment. One horse became obese again subsequent to pasture turn-out in the spring–summer season posttreatment, but, according to the owner, primary care veterinarian (D.R.T.) and hoof care professional (A.S.), remained sound while obese.

Results of long-term follow-up (2-6 years after initial onset of laminitis) of 12 horses indicated that 8 of 12 owners considered their horse to be rideable (2 horses were lost to follow-up and 2 horses were euthanized due to nonlaminitis-related diseases; 1 acquired chronic neurologic deficits, and 1 has pre-existing arthritis of the proximal pelvic limbs). Only 1 owner reported transient foot pain due to apparent laminitis relapse after allowing the horse unlimited access to pasture, resulting in body condition score of 8 in conjunction with a lapse in hoof care. One other owner reported recurrent abscess episodes in one foot (Table 2).

4. Discussion

It is likely that all horses in this study suffered from endocrinopathic (grass-induced) laminitis because each was obese and there was no history or clinical evidence of an acute systemic inflammatory disease or clinical signs of pituitary disease. It is possible that some of these horses suffered from pituitary pars intermedia dysfunction, but the horses had no clinical signs of this syndrome before or after the study. Because of the retrospective nature of this study, insulin concentrations were determined only for a few horses, and other measures of glucose homeostasis were not performed in any of the horses; therefore, the data were not analyzed.

The prognosis for return to former athletic function for horses with >11.5° of distal phalangeal rotation is considered poor, and the prognosis for horses with 5.5° to 11.5° of rotation is guarded [1]. Even though all horses in this study had >5.5° rotation of the distal phalanx and 6 had >11.5° of rotation, all returned to their prelaminitis level of soundness as evaluated by owners. While it would have been ideal for a blinded unbiased clinician to have performed lameness evaluation on each of these horses, they were managed as field cases by a single veterinarian (D.R.T.), and there was no clinical indication for objective evaluation of gait at the time of initial and subsequent evaluations.

After laminar failure, the primary mechanical force working to separate the laminae is the weight of the horse opposed by the hoof wall [19]. When the hoof wall bears weight, the lamellae are forced to suspend the horse’s weight and bear foot impact forces. Even though tension of the deep digital flexor muscle and tendon exerts a rotational force on the distal phalanx, we suspect that tension of the deep digital flexor tendon did not result in added stress to laminae in these horses because the hoof wall in the toe region was trimmed so it remained out of contact with the bearing surface.

Because a significant overall reduction of the palmar angle of these horses was detected (from a pretreatment mean of 11.75° to a post-treatment mean of 5.46°), this method of laminitis management should be further investigated as an alternative nonsurgical method for restoring alignment of the distal phalanx [20] in laminitic horses.

The treatment effect on palmar angle reduction was statistically larger for chronic cases than for acute cases.

Fig. 4. Oblique radiographic view of the left front foot of one of the subject horses. Note that the red line, which represents the hoof wall, is not parallel to the yellow line, which represents the cortical surface of the distal phalanx. This radiograph provides evidence that obesity-associated laminitis may produce lamellar pathology resulting in wall flares in the quarters as well as in the toe regions [16].

The authors believe that the amount of lamellar separation at the quarter walls (or anywhere around the perimeter of the foot) may be as significant as the amount of lamellar separation in the region of the toe [16] (Fig. 4). Eliminating or at least reducing weight-bearing by the entire perimeter of the hoof wall (with the exception of the heel buttress) may be important in stopping and possibly reversing distal decent of the third phalanx in horses with either acute or chronic laminitis. Reduction or elimination of weight-bearing by the hoof wall theoretically decreases strain on laminar attachments by removing mechanical forces, thus minimizing or preventing additional rotation or sinking [21]. Elimination of weight-bearing by the hoof wall may also reverse distal descent of the distal phalanx in some horses as demonstrated in lateromedial radiographs of the right front foot of horse 11 (Fig. 5) obtained at initial evaluation and 2 years 7 months later.

Fig. 5. The radiographs8 show that the coronary band to extensor process distance (CE) may become smaller over time in this hoof care system. The radiograph at right (CE ¼ 13 mm) is a follow-up examination of the right front foot 2 years and 7 months after the initial evaluation in the radiograph on the left (CE ¼ 17 mm).

This hoof care method used the sole to support the distal phalanx. While using the sole to support the distal phalanx, it is important that the sole be protected during weight-bearing yet not be subjected to pressure during hoof flight. When sole thickness is <12 mm and/or when weight-bearing by the hoof wall is eliminated, excess pressure on the solar corium can result. When the sole under the margin of the distal phalanx was less than 7 mm, bulging, or cracked, an air space had been established in the hoof pad under the solar margin. We suspect that lack of solar pressure during hoof flight is critical to maintaining solar blood flow to prevent solar corium injury. Each method of solar protection used in these cases was intended to release pressure on the solar corium during hoof flight. Efforts were made to protect the laminar corium by allowing the hoof wall to bear little or no weight by beveling the hoof wall away from the ground and not allowing application of a shoe to the hoof wall (Fig. 2).

When the horse’s foot is bearing weight, arterial blood flow to the foot is occluded, in part, by force of the deep digital flexor tendon on the medial and lateral digital arteries. This is a normal physiological event, and it is the likely mechanism preventing backflow of arterial blood during the loading phase of the stride [22]. When the foot does not bear weight, arterial blood flow to the foot is restored. We suspect that exercise of these horses caused an intermittent lack of pressure to the sole and prevented ischemia of the laminar and solar corium that occurs when the horse’s foot bears weight continuously. It is important to understand that these horses were exercised with the hoof wall bevelled to minimize weight-bearing by the hoof wall, the sole well protected by soft pads held on the hoof by hoof boots or occasionally casts and a near normal palmar angle of less than 10°. If horses did not land heelfirst in their protective hoof wear during exercise, exercise was discontinued until this desired hoof landing was achieved by altering the hoof mechanics and padding [16]. The exercise regimen seemed to alleviate pain in these horses as shown by increased comfort (decreased pain – modified Obel pain scale) [22] during and after exercise. Exercise is recommended for horses suffering from insulin sensitivity [9,11]. This laminitis management method may provide a means of exercising insulin resistant laminitic horses without jeopardizing their hooves. These horses were fed a diet that was intended to minimize the intake of nonstructural carbohydrates, provided free-choice access to hay and also provide a mineral-balanced diet.

Fig. 6. Radiographs8 show change in the dimension of the soft tissues of the heel and shortening of the digital breakover over 2 years 6 months (left image, April 2, 2009; right image, October 20, 2011). Note that the weight-bearing surface of the heel region has increased 6 mm in length (from 9.3 to 9.9 cm). Also note the realignment of the bones of the distal limb and the lowering of the palmar angle (pre: 22°; post: 12°).

Because none of the types of hay fed to the 14 horses of this study were tested for nutritional content and owners soaked the hay for various amounts of time, the actual dietary intake of these horses could not be determined retrospectively. The hay “as fed” combined with the exercise program “as applied” did cause a statistically significant decrease in body condition score, which indicates that the diet and exercise regime was clinically appropriate. However, close attention to diet to include nutrient testing of hay fed to obese laminitic horses would obviously be superior to the empirical feeding programs of these horses.

This method of laminitis management apparently alleviated pain and returned this group of horses to their former level of athletic ability despite suspected minor to moderate nutritional imbalance, distal phalanx remodelling in some horses, and incomplete resolution of hoof wall rotation in some horses (Fig. 5). It is hypothesized that increased heel volume (Fig. 6) may in some way compensate for distal phalanx remodelling and laminar damage as altered heel dimension similar to the improved heel angles described by Clayton et al [23] was also noted in these horses.

As none of these horses was hospitalized during the laminitis treatment period, owner compliance with daily care recommendations likely played a role in the favorable outcome in these horses. Successful management of obese, laminitic horses requires a concentrated long-term team effort among the veterinarian, the owner, and the hoof care professional to manage the horse’s diet, exercise, hoof care, and medical needs. In this series of cases, the radiographic parameters of the hoof improved, and lameness decreased during the period of dietary restriction, weight loss, and exercise.

Using the described management protocol, 14 of 14 laminitic horses with rotation >=5° and a guarded prognosis returned to their prelaminitis level of soundness by the time of the endpoint radiographic evaluation. Long-term follow-up survey indicated that most of these horses maintained the same level of soundness without incidence of laminitis recurrence or hoof abscess formation. This method of laminitis management is effective and warrants further evaluation.

Acknowledgments

We would like to acknowledge the dedicated owners and care takers of the horses described in the manuscript.

References

[1] Stick JA, Jann HW, Scott EA, Robinson NE. Pedal bone rotation as a prognostic sign in laminitis of horses. J Am Vet Med Assoc 1982; 180:251–3.
[2] Hunt RJ. A retrospective evaluation of laminitis in horses. Equine Vet J 1993;25:61–4.
[3] Coffman JR, Hammond LS, Garner HE, Thawley DG, Selby LA. Haematology as an aid to prognosis of chronic laminitis. Equine Vet J 1980;12:30–1.
[4] Coffman JR, Johnson JH, Finocchio EJ, Guffy MM. Biomechanics of pedal rotation in equine laminitis. J Vet Med Assoc 1970;156: 219–21.
[5] Colles CM, Jeffcott LB. Laminitis in the horse. Vet Rec 1977;100: 262–4.
[6] Cripps PJ, Eustace RA. Factors involved in the prognosis of equine laminitis in the UK. Equine Vet J 1999;31:433–42.
[7] Asplin KE, Patterson-Kane JC, Sillence MN, Pollitt CC, McGowan CM. Histopathology of insulin-induced laminitis in ponies. Equine Vet J 2010;42:700–6.
[8] de Laat MA, Kyaw-Tanner MT, Nourian AR, McGowan CM, Sillence MN, Pollitt CC. The developmental and acute phases of insulin-induced laminitis involve minimal metalloproteinase activity. Vet Immunol Immunopathol 2011;120:275–81.
[9] Freestone JF, Beadle R, Shoemaker K, Bessin RT, Wolfsheimer KJ, Church C. Improved insulin sensitivity in hyperinsulinaemic ponies through physical conditioning and controlled feed intake. Equine Vet J 1992;24:187–90.
[10] Stewart-Hunt L, Geor RJ, McCutcheon LJ. Effects of short-term training on insulin sensitivity and skeletal muscle glucose metabolism in Standardbred horses. Equine Vet J Suppl 2006;36: 226–32.
[11] Frank N, Geor RJ, Baily SR. Equine metabolic syndrome. ACVIM consensus. J Vet Intern Med 2010;24:467–75.
[12] Obel N. Studies of the Histopathology of Acute Laminitis [dissertation]. Uppsala, Sweden: Almqvist and Wilksells Boktryckeri AB; 1948.
[13] Taylor DR. Radiographic imaging of the laminitis patient. In: Ramey P, editor. Care and rehabilitation of the equine foot. Lakemont, GA: Hoof Rehabilitation Publishing LLC; 2011. p. 234–63.
[14] Redden RF. Shoeing the laminitic horse. In: Norwood G, editor. Proceedings of the Forty-third Annual Convention of the American Association of Equine Practitioners. Phoenix, Arizona, USA: AAEP Publishing; 1997. p. 356–9.
[15] Redden RF. Clinical and radiographic examination of the equine foot. In: Bramlage L, editor. Proceedings of the Forty-ninth Annual Convention of the American Association of Equine Practitioners. New Orleans, Lousianna, USA: AAEP Publishing; 2003. p. 169–85.
[16] Ramey P, editor. Care and rehabilitation of the equine foot. Lakemont, GA: Hoof Rehabilitation Publishing LLC; 2011. p. 284–352.
[17] National Research Council nutrient requirements of horses, 6th rev. ed. Washington, DC: National Academies Press; 2007.
[18] Henneke DR. A condition score system for horses. Equine Pract 1985;8:13–5.
[19] Steven D. Functional anatomy of the horse’s foot. Pract 1981;3:22–7.
[20] O’Grady SE. How to restore alignment of P3 in horses with chronic laminitis. In: Bramlage L, editor. Proceedings of the Fortyninth Annual Convention of the American Association of Equine Practitioners. New Orleans, Lousianna, USA: AAEP Publishing; 2003. p. 328–36.
[21] Ramey P. Care and rehabilitation of the hoof walls and lamellar attachment. In: Ramey P, editor. Care and rehabilitation of the equine foot. Lakemont, GA: Hoof Rehabilitation Publishing LLC; 2011. p. 345.
[22] Van Eps A, Collins SN, Pollitt CC. Supporting limb laminitis. Advances in laminitis. Part II. Equine Pract 2010;26:287–302.
[23] Clayton HM, Gray S, Kaiser LJ, Bowker RM. Effect of barefoot trimming on hoof morphology. Aust Vet J 2011;89:305–11.

Written by Anne Riddell June 2006 Board Certified by the American Hoof Association

Have you ever wondered what the inside of your horse’s hoof looks like if you were able to peer inside? The horse’s hoof is an ever changing and adapting vascular mechanism. The outside wall mirrors the inside of the hoof, especially in the area of the sensitive laminae, otherwise known as the white line. The laminae are composed of the epidermal laminae and the dermal laminae. The two tightly fit together like velcro interlocking and securing the outside capsule of the foot to the inside structure. This bond is virtually indestructible through force unless it is otherwise compromised by a metabolic or toxic effect taking place in the horse’s system.

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Dalla pagina “Articoli” della American Hoof Association

Laminitis is a word no horse owner wants to hear associated with her horse. It is a crippling disorder that takes weeks or even months for the horse to recover from, and that is if all causative factors are removed and the best equine husbandry is provided. It can be permanently debilitating if not dealt with properly and promptly, leading to much pain and suffering for the horse.

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In questa sezione “Laminite” del sito potete leggere qualche cosa su questo argomento centrale che è stato ed è continuamente dibattuto. Se siete colpiti in prima persona perché lo é il vostro cavallo non siete nella posizione ideale per leggere e studiare ma volete risposte immediate e convincenti. Con Jackson e con Ramey successivamente è stata rivoluzionata la tecnica di confronto con la laminite nel suo insieme. Non sono coloro che non la conoscono a potervi aiutare. Semplicemente non hanno successo ed il loro insuccesso é decretato dagli innumerevoli “decessi assistiti”. La laminite non sarebbe la seconda causa di morte fra i cavalli dopo la colica se fosse gestita correttamente. Per i proprietari é difficile controllare l’ansia ed é normale trovarsi disarmati di fronte a persone che crediamo specializzate. I programmi di insegnamento vaghi e lacunosi, assolutamente non aggiornati dei corsi di studio universitari precludono ogni possibilità. A questo si aggiunge l’insieme delle miserie che spesso accompagnano ogni professione. Con le tecniche di riallineamento espresse nel protocollo di riabilitazione Ramey-Taylor accompagnate all’indispensabile cambio di gestione ed alimentazione i risultati sono sicuri. Se avete tempo e riuscite ad avere la serenità necessaria leggete il rapporto della dottoressa Taylor in questa sezione. Solo in casi estremamente gravi è lecito prendere in considerazione l’eutanasia. Sentitevi liberi di chiamare e chiedere aiuto.

Continuando in questa presentazione ed illustrazione inizio elencando sinteticamente tre plausibili cause di laminite sperando di contribuire alla comprensione con ulteriori esempi e considerazioni:

Metabolica. Meccanica? Ipossica?

Non mi vergogno di presentare questa semplificazione tanta è l’ignoranza diffusa ad ogni livello e soprattutto la speculazione di cui sono oggetto questi animali e di loro proprietari. Metabolica quando a causa di un disordine metabolico vengono meno o risulta allentata la forza con la quale sono connesse parete e strutture interne. Meccanica quando, una parete trascurata e troppo lunga con riferimento al piano della suola, viene ad ogni passo “strappata” dalla forza che il terreno esercita su di essa. Ipossica quando allo zoccolo, a causa della ferratura o dello stazionamento su una lettiera morbida con conseguente mancato meccanismo dello zoccolo, viene a mancare un adeguato apporto di ossigeno e/o nutrimento.

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Brigitte é una femmina araba sulla trentina. In queste fotografie la sequenza dei nove mesi di pareggio. Avrà una vecchiaia serena se la padrona, accorta, terrà a freno il suo appetito d’erba. Il recupero è stato costante.

Brigitte, nonostante l’età, i trascorsi e la completa saldatura delle articolazioni tra prima e seconda falange si muove con sorprendente disinvoltura ed è un piacere vederla andare a spasso per il maneggio.

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(Inverno 2012)

Mi scuso per la presentazione e la mancanza delle fotografie. Abbonatevi a “The horses hoof”, sono solo 15 dollari!

Sono fiero di presentare questo appello di J.Jackson che rispecchia al 100% la mia posizione, già espressa in questa pagina in (Il mio punto di vista ed alcune riserve finali. L’etica?)

Laminitis and PETA (Poor Excuse for the Treatment of Animals) A Wake-up Call to the International Laminitis Research Community and Organizations for the Humane Care of Equines Jaime Jackson, AANHCP Executive Director

“This study involved 16 adult horses, ranging in age from 6 to 14 yr old (mean, 11 yr old). The horses were euthanized by using a penetrating captive bolt, as approved by the Report of the American Veterinary Medical Association’s Panel on Euthanasia.” – Hood, D.M., Grosenbaugh, D.A., Mostafa, M.B., Mor- gan, S.J. and Thomas, B.C. (1993) The role of vascular mechanisms in the development of acute equine laminitis. J. Vet. Intern. Med. 7, 228-234.

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