DeniseMc in gray

Conceivably, a hoof with poor circulation could be damaged (ie cracked bar)

Please explain the exact process by which you feel a cracked bar(s) could cause "poor circulation" to such an extent that white blood cells would not be present at any invasion of microorganisms.

and bacteria could enter and just fester (digesting tissue) without forming an actual abscess; actually that explains alot.

Microorganisms cannot enter tissue with ongoing life processes without triggering an immune reaction from the horse's body. You are confusing an infection with an abscess: All infections are not abscesses, but all septic abscesses are infections.

With circulation, the body recognizes the festering damage caused by the bacteria, caused by the trauma and then forms the abscess, expelling it, removing the damaged horn in the process.

Abscesses are characterized by localization, not circulation.

"Abscess, n.: A collection of pus formed by tissue destruction in an inflamed area of a localized infection... A cavity that is formed by liquefactive necrosis within solid tissue." The American Heritage® Medical Dictionary Copyright © 2007 [emphasis mine]

While minor infections of the hoof sometimes resolve without intervention, abscesses within the hoof capsule can be extremely debilitating because they are effectively encapsulated by the sole, coffin bone and hoof wall - which means the line of least resistance for purulence under hydraulic pressure is upwards, through soft, enervated, tissue. If left untreated, some solar abscesses eventually undergo spontaneous drainage at the coronary band; however, surgically establishing solar drainage and mechanically protecting the wound site is the usual treatment of choice for most equine practitioners as it does not require the horse to live in pain for days, possibly weeks, until the abscess undergoes spontaneous drainage.

I did not say cracked bars cause poor hoof circulation. Cracked bars are usually caused by poor hoof form (such as long, underrun heels or not trimming bars) with the poor hoof form causing the poor circulation. Poor circulation means poor blood supply, poor immune response.
Denise

Theories, all theories. As are most things hoof related.

DeniseMc in gray

I did not say cracked bars cause poor hoof circulation. Cracked bars are usually caused by poor hoof form (such as long, underrun heels or not trimming bars) with the poor hoof form causing the poor circulation. Poor circulation means poor blood supply, poor immune response.

Please cite any peer-reviewed source that suggests "poor hoof form" causes poor (impaired?) circulation within the hoof capsule (i.e., from PDA to PDV). Please cite any peer-reviewed source that suggests "poor hoof form" is a cause of a poor (impaired?) immune response.

EQUINE DIGITAL VENOGRAM IN RELATION TO THE BIOMECHANICS
OF THE FOOT
Lorenzo D’Arpe Med Vet*, Luigi Michele Coppola Med Vet *, Prof. Daniele Bernardini*,
Stefano Masiero Med Vet#.
* Dipartimento di Scienze Cliniche Veterinarie, Università di Padova (Italia)
# Libero professionista, Vicenza.
Introduction. There are many existing scientific studies on centre of pressure or mass in the equine
foot; many techniques and instruments have been used in these studies (Xu H et al. 1999, Arabian
AK et al. 2001 and Leveillard D. 2005) and this has helped to understand biomechanics and dynamic
effects on gait analysis related to trim and shoeing (Willemen et al. 1996, Wilson AM et al.
1998, Xu H et al. 1999, Van Heel MC et al. 2004, Van Heel MC et al. 2005).
Many studies have been oriented to evaluate the relationship between the body weight load and
anatomical changes of the foot (Crevier-Denoix N et al. 2001, Hobbs SJ et al. 2004, Burn JF et al.
2001, Colles CM et al. 1989 and Redden RF. 2003).
Olivier A et al. (1989) underlined the effect of weight loading on the coronary band and interstitial
fluid pressure in horses.
Pietra M et al. (2004) highlighted the influence of weight bearing on Doppler evaluation of lateral
palmar digital arteries in healthy horses.
The aim of this research is the visualization of fine detailed variations of vascular bed utilizing digital
venography and the relationship to the biomechanical effects of changing the Palmar Angle (PA)
to the ground line and weight-bearing position.
Materials and methods. The X-ray examinations were performed at Veterinary Clinical Sciences
Dep. of Padua, on thoroughly cleaned unshod feet of six horses not referred for foot problems, 3
chronic sub-clinical laminitis and 3 sound, the horses were aged between 5 and 14 years, body
weight between 400 and 550 kg.
We used a wood-iron podoblock specially designed and realized with Moreau X. (height 8,9 cm,
length 16,4 cm, with 16,4 cm, able to change PA between –15° and +15° with a step every 5°), it
was placed under the weight bearing frontfoot and radiographed with principal tubulus corneus
(Caudron I. et al 1997) along dynamic podoblock’s sagittal axis, the neck of the horse was maintained
along body sagittal axis at same level of withers during the x-ray examination, in order to
equally distribute horses weight.
Static Centre of Pressure (SCP) was identified following the technique described by Leveillard D.
(2005) with the horse standing squarely on 4 feet (4SCP) and on 3 feet (3SCP). We positioned the
4SCP or 3SCP, the weight force application point, under the center of the dynamic podoblock.
In order to evaluate the difference of weight force in different postures we calculated the load on
each front foot in both postures with a digital scale.
The foot was placed medially in contact with X-ray cassette in order to reduce magnification phenomenon
as much as possible. Konica x-ray films and radiological apparatus (Pollux 700 “Odel
srl”) were used. X-ray beam was oriented in the middle of solar aspect of PIII perpendicular to cassette.
X-ray images were taken in latero-medial projection at a distance of 80 cm (D’Arpe L. et al.
2006).
Seven x-ray images were performed moving dynamic podoblock’s angle of 5° every 30 sec. and
without moving X-ray machine from the ground. Two venography examinations were performed on
each foot in order to relatively reduce the importance of perivascular diffusion and blood dynamic
effects correlated with venography technique (D’Arpe 2004). First venography exam was performed
by injecting contrast liquid (Iopamidolo 150 mg)** at –15°, progressively modified to +15°. Sec-
Published in IVIS with the permission of SIVE Close window to return to IVIS
Proceedings of the European Equine Meeting of the Year 2008 - XIV SIVE - FEEVA Congress, Venice, Italy
360
ond, exam (one week later), vice versa injecting at +15° progressively modified to –15°.
Results
After injecting at –15° and +15°
-15° Absent vascularization of coronary bend and dorsal laminar vessels
-10° Poor vascularization of coronary bend and dorsal laminar vessels
-5° Still poor but improved
0° Close to normal
+5° Still poor but improved
+10° Poor vascularization of bulbar vessels
+15° Absent vascularization of bulbar vessels
Discussion. We have not noticed any significant variation in examinations injected at –15° and
+15°.
According to Pietra M. et al. (2004) we noticed a considerable difference between tripodal and
quadripodal posture. We have correlated this to weight load variation between 4SCP and 3SCP;
each front foot was charged of 115-155 kg in 4SCP and 220-310 kg in 3SCP.
We observed, according to previous observations of Thompson KN et al. (1993), Crevier-Denoix N
(2001) and Redden RF. (2003), that Deep Digital Flexor Tendon (DDFT) tension played an important
role for the vascular bed to fill with the contrast liquid.
The results obtained, relative to vascular changes correlated to PA and consequently DDFT tension
changes, showed that a negative PA induced compression of coronary band and dorsal laminar vessels;
and a positive PA induced the compression of bulbar vessels.
Conclusion. This study permitted us to visualize how vascular foot bed can be modified by little
changes of PA correlated to DDFT tension and weight-load force differences in standing posture.
We conclude that manipulating PA is important to mechanically improve the vascularization of the
foot.
**Iopamiro 300, fl 50 ml (Bracco SpA Milano)
Bibliografia disponibile presso gli autori
Indirizzo per la corrispondenza/Address for correspondence:
Lorenzo D’Arpe
Dipartimento di Scienze Cliniche Veterinarie, Università di Padova, V.le dell’università 16,
Legnaro di Padova, Italia. e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Published in IVIS with the permission of SIVE Close window to return to IVIS
Proceedings of the European Equine Meeting of the Year 2008 - XIV SIVE - FEEVA Congress, Venice, Italy
__________________

The above study suggests to me that changing angles of the hoof, whether by wedging or leaving heels or toes too high would create disruptions in the blood supply to either toe or heel


Isn't it obvious if blood circulation is hampered to any area you will get an impaired repair mechanism?

DeniseMc in gray, stuff deleted

EQUINE DIGITAL VENOGRAM IN RELATION TO THE BIOMECHANICS
OF THE FOOT

Conclusion. This study permitted us to visualize how vascular foot bed can be modified by little changes of PA correlated to DDFT tension and weight-load force differences in standing posture.
We conclude that manipulating PA is important to mechanically improve the vascularization of the foot.

The above study suggests to me that changing angles of the hoof, whether by wedging or leaving heels or toes too high would create disruptions in the blood supply to either toe or heel

In terms of supporting your claims, the observation is fatally flawed because it deals only with the influence of palmar angle and load on vascularization of the hoof, and only under static conditions. No baseline for minimal requirements of circulation was established and dynamic circulation was not measured. Unfortunately, failing a baseline and dynamic measurement of blood volume, there is nothing in the six-horse observation that suggests "poor hoof form" is wholly or partially responsible for impaired circulation or suppression of the immune system of horses.

Isn't it obvious if blood circulation is hampered to any area you will get an impaired repair mechanism?

It's obvious to me that you're trying to compare apples to oranges by attempting to extrapolate data that does not support your claims. Unless one establishes a baseline and determines the volume of blood required by tissue within the hoof to carry on life processes under both static and dynamic conditions, the BUA's claims of circulation impairment and immune system suppression due to "poor hoof form" are nothing more than dogmatic conjecture.

Mark_Gough wrote:
Good post Mark.

I can certainly speculate (hypothesize) that poor hoof form is responsible for impaired circulation based on the data; just can't "prove" it. You asked for any studies which "suggest" poor hoof form causes poor hoof circulation. You did not ask for "proof".

DeniseMc

I can certainly speculate (hypothesize) that poor hoof form is responsible for impaired circulation based on the data; just can't "prove" it.

Logically, the data suggest only that changes in palmar angle may affect vascularization of the hoof under static conditions; the "improvement" claimed by the observation is not substantiated by previously established baseline requirements and the data obtained cannot be extrapolated to apply under dynamic conditions.

You asked for any studies which "suggest" poor hoof form causes poor hoof circulation. You did not ask for "proof".

Due to its obvious flaws, the six-horse observation does not suggest "poor hoof form" is related to either impaired circulation or a compromised immune response. Essentially, the observation suggested that when a horse is standing still, the amount of blood circulating in the hoof can be changed by manipulating the palmar angle by means of reducing/increasing tension of the DDFT - at the time. [Extra credit: Why is this relevant?]

Denise,
The reference you provided is from a conference proceedings, and these are not peer reviewed. Lest you think I am being unfair, I would suggest that some of my force plate work is NOT subject to peer review. I have presented some preliminary conclusions at conferences, but these are not peer reviewed.

I do not believe any venogram study has been subject to a peer review process.

It seems this discussion goes round & round. I say no one modality of hoofcare works on all horses for all situations. Several years ago at the Strasser seminar at Tufts, the moderator asked Mike Wildenstein if the barefoot movement has been dertimental to his business, Mike replied, "We are seeing a great deal more business here from either horses trying to go without shoes and are lame or from botched jobs of bare foot trimmers!"

Now that I am the Resident Farrier at Cornell, many of the lame horses that I see are need of shoes, quite often ridden extensively without shoes and became lame, due to the abscence of shoes. Often they are foot sore, thin soles and have abscesses in the white line area from peebles penetrating the junction of sole and hoof wall, right where a shoe would have protected! Imagine that!

Steve Kraus, CJF

Hi Patrik,
You are right; I wrongly assumed that it was peer reviewed.

No, I would never think that.

That is interesting. Why do you think that is?

Enough to make one dizzy, for sure.

I don't disagree.

And no one modality of hoofcare works on all horses for all situations. Shoeing is one choice someone could make. Some alternatives I would consider are a bead of Superfast with Soleguard, removable boots or use some of that DuraSole product that has label claims of being "extremely effective in the relief of sole soreness" and "used extensively for transitioning horses from shod to barefoot" (yes, he really says that).
Denise

Just curious, do you believe the claims that a straight HPA (as verified by radiographs under static conditions) is necessary and a goal of biomechanical manipulation for optimal hoof health and function? I think I know what your answer will be.........

DeniseMc wrote:
I lit search for "equine venogram foot" provides a bunch of references for publications such as Vet Clinics of North America. While a nice publication, this is more likely to print the experiences of clinicians. To my knowledge, there has been no research assessing the repeatability of venograms, much less the accuracy of the procedure. Part of the issue is that there is no "gold standard" regarding measuring circulation in the equine foot. Experts still disagree about how circulation occurs. Some reasonable questions:
1. Is pushing on a syringe an accurate method of delivering the same amount of contrast material?
2. If (as your proceeding notes suggest) posture matters, does standing a horse on radiology blocks (front only) affect the venogram?
3. Does posture matter?
4. Do subtle weight shifts during the procedure affect the results?
5. How does the normal vasodialation/constriction (horses experience episodes of both each day) affect the results?

I am not saying venograms do not work, but they are not universally accepted as an accurate measuring procedure. It drives me nuts when people
assume that it is not only accurate, but that we can determine how treatments (trim vs shoes) affect the circulation that we can't accurately measure. See the dilemma? It is like building a house of cards....