R
Radiographs (x-rays)
Regional Limb Perfusion
Resection - of hoof wall
Resveratrol
Retained Placenta
RISQI
Regional Limb Perfusion
Resection - of hoof wall
Resveratrol
Retained Placenta
RISQI
Radiographs (x-rays)
Radiographs should always be taken when a horse has had laminitis.
See Understanding x-rays/radiographs
Radiograph technique
Use digital radiographs (see below) if at all possible.
Thoroughly clean and ideally trim the foot.
Always place a radiodense marker (a clench or length of straight wire will do - it can be taped on) on the dorsal hoof wall (i.e. at the toe) extending right to the coronary band/hair line (although digital radiographs are very clear, without this marker it is almost impossible to accurately assess sinking)
A radiodense marker (a sawn-off drawing pin is ideal) can be placed just back from the apex of the frog - this is particularly useful if the horse is likely to be shod with frog support.
The horse will need to stand on a wooden block and should be weight bearing, therefore either the leg not being x-rayed should be held up, or both (e.g.front) legs should be on blocks.
Centre beam 1-2 cm above the block in the middle of the foot
It is conventional for markers to be placed on the dorsal or lateral aspect of the foot or limb (this is particularly important for DP views).
Lateral-medial radiographs of P3 help assess rotation and sinking.
Dorsopalmar radiographs of P3 can be helpful in assessing lateral-medial hoof imbalance
Equine Radiography: Positioning Techniques & Tips for Acquiring Good Images - Shalyn J Crawford 2015
Front and Hind Limb Radiology - Christina Garloff May 2012
Explaining Laminitis and its Prevention - Robert Eustace: X-ray technique
Laminitis Radiology - Chris Pollitt
The Phalanges
Radiology of the Equine Limbs
Radiography - John the Vet
Radiographic Examination of the Equine Foot - W Rich Redding
Radiography and radiology of the equine foot - R Weller - 50th BEVA Congress 2011
O'Brien's Radiology for the Ambulatory Equine Practitioner - Timothy R O'Brien (2005)
Equine distal limb normal radiographic anatomy - Karl L Anderson University of Minnesota
Atlas of Diagnostic Radiology of the Horse - Diseases of the Front and Hind Limbs - Kees J. Dick and Ilona Gunsser
The Value of Quality Foot Radiographs and Their Impact on Practical Farriery - Randy Eggleston, AAEP 2012
Can Hoof Wall Radiographs Help Identify Early Laminitis? - Casie Bazay, www.thehorse.com, Dec 2015
Sherlock C, Parks A
Radiographic and radiological assessment of laminitis
Equine Veterinary Education October 2013 Vol 25, Issue 10 Pages 524-535 (Full)
Collins SN, Dyson SJ, Murray RC, Newton JR, Burden F, Trawford AF
Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys
Am J Vet Res. 2012 Aug;73(8):1207-18. doi: 10.2460/ajvr.73.8.1207
Eggleson RB
Value of Quality Foot Radiographs and Their Impact on Practical Farriery
AAEP Proceedings 2012 Vol. 58
Baker WR Jr
Treating laminitis: beyond the mechanics of trimming and shoeing
Vet Clin North Am Equine Pract. 2012 Aug;28(2):441-55. doi: 10.1016/j.cveq.2012.05.004
"The use of radiographs for diagnosis and interpretation of laminitis is an absolute necessity..."
Radiographs are useful for diagnosis, prognosis and to guide treatment. Lateral views should be taken with both feet on equal height blocks and the main beam focused at the solar margin of P3, with the foot touching the casette to avoid magnification. Variation from the correct technique will result in artifacts and false information. It is essential to mark the dorsal hoof wall and frog apex, e.g. with barium paste. Useful measurements include the coronary/extensor distance, sole depth, the horn:lamellar distance, and the palmar angle. The dorsal angle is not (particularly) important, and is influenced by deformity of the outer wall.
Page BT, Bowker RM, Ovnicek G, Hagen TL
How to Mark the Foot for Radiography
AAEP Proceedings 1999 Vol 45
See Understanding x-rays/radiographs
Radiograph technique
Use digital radiographs (see below) if at all possible.
Thoroughly clean and ideally trim the foot.
Always place a radiodense marker (a clench or length of straight wire will do - it can be taped on) on the dorsal hoof wall (i.e. at the toe) extending right to the coronary band/hair line (although digital radiographs are very clear, without this marker it is almost impossible to accurately assess sinking)
A radiodense marker (a sawn-off drawing pin is ideal) can be placed just back from the apex of the frog - this is particularly useful if the horse is likely to be shod with frog support.
The horse will need to stand on a wooden block and should be weight bearing, therefore either the leg not being x-rayed should be held up, or both (e.g.front) legs should be on blocks.
Centre beam 1-2 cm above the block in the middle of the foot
It is conventional for markers to be placed on the dorsal or lateral aspect of the foot or limb (this is particularly important for DP views).
Lateral-medial radiographs of P3 help assess rotation and sinking.
Dorsopalmar radiographs of P3 can be helpful in assessing lateral-medial hoof imbalance
Equine Radiography: Positioning Techniques & Tips for Acquiring Good Images - Shalyn J Crawford 2015
Front and Hind Limb Radiology - Christina Garloff May 2012
Explaining Laminitis and its Prevention - Robert Eustace: X-ray technique
Laminitis Radiology - Chris Pollitt
The Phalanges
Radiology of the Equine Limbs
Radiography - John the Vet
Radiographic Examination of the Equine Foot - W Rich Redding
Radiography and radiology of the equine foot - R Weller - 50th BEVA Congress 2011
O'Brien's Radiology for the Ambulatory Equine Practitioner - Timothy R O'Brien (2005)
Equine distal limb normal radiographic anatomy - Karl L Anderson University of Minnesota
Atlas of Diagnostic Radiology of the Horse - Diseases of the Front and Hind Limbs - Kees J. Dick and Ilona Gunsser
The Value of Quality Foot Radiographs and Their Impact on Practical Farriery - Randy Eggleston, AAEP 2012
Can Hoof Wall Radiographs Help Identify Early Laminitis? - Casie Bazay, www.thehorse.com, Dec 2015
Sherlock C, Parks A
Radiographic and radiological assessment of laminitis
Equine Veterinary Education October 2013 Vol 25, Issue 10 Pages 524-535 (Full)
Collins SN, Dyson SJ, Murray RC, Newton JR, Burden F, Trawford AF
Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys
Am J Vet Res. 2012 Aug;73(8):1207-18. doi: 10.2460/ajvr.73.8.1207
Eggleson RB
Value of Quality Foot Radiographs and Their Impact on Practical Farriery
AAEP Proceedings 2012 Vol. 58
Baker WR Jr
Treating laminitis: beyond the mechanics of trimming and shoeing
Vet Clin North Am Equine Pract. 2012 Aug;28(2):441-55. doi: 10.1016/j.cveq.2012.05.004
"The use of radiographs for diagnosis and interpretation of laminitis is an absolute necessity..."
Radiographs are useful for diagnosis, prognosis and to guide treatment. Lateral views should be taken with both feet on equal height blocks and the main beam focused at the solar margin of P3, with the foot touching the casette to avoid magnification. Variation from the correct technique will result in artifacts and false information. It is essential to mark the dorsal hoof wall and frog apex, e.g. with barium paste. Useful measurements include the coronary/extensor distance, sole depth, the horn:lamellar distance, and the palmar angle. The dorsal angle is not (particularly) important, and is influenced by deformity of the outer wall.
Page BT, Bowker RM, Ovnicek G, Hagen TL
How to Mark the Foot for Radiography
AAEP Proceedings 1999 Vol 45
Film radiograph
|
Digital radiograph
|
Film v digital radiographs. 2 x-rays taken of the same horse, left fore, a few days apart, following acute laminitis. From the film x-ray on the left the first vet diagnosed 4' rotation. From the digital x-ray on the right taken a few days later the second vet diagnosed no rotation.
The x-ray on the left is an example of a bad x-ray - no markers were used, the horse was not weight bearing, the whole hoof is not shown therefore the relationship of P3 to the hoof capsule cannot be seen.
The x-ray on the right is an example of a good x-ray - markers positioned correctly and can be used for scale measurements, the horse was weight bearing, the relationship of P3 to the well balanced hoof capsule is clearly shown, the x-ray beam was perpendicular to the hoof.
These x-rays cost much the same! Always ask for digital x-rays, ideally where the x-rays are processed on site - if your vet does not have suitable equipment, they should be able (and happy) to recommend another vet who does.
The x-ray on the left is an example of a bad x-ray - no markers were used, the horse was not weight bearing, the whole hoof is not shown therefore the relationship of P3 to the hoof capsule cannot be seen.
The x-ray on the right is an example of a good x-ray - markers positioned correctly and can be used for scale measurements, the horse was weight bearing, the relationship of P3 to the well balanced hoof capsule is clearly shown, the x-ray beam was perpendicular to the hoof.
These x-rays cost much the same! Always ask for digital x-rays, ideally where the x-rays are processed on site - if your vet does not have suitable equipment, they should be able (and happy) to recommend another vet who does.
Regional Limb Perfusion (RLP)
Regional Limb Perfusion (RLP) is the administration of antibiotics directly into an affected leg through a vein (intravenous - although intraosseous RLP can also be done).
It enables much higher levels of antibiotics to reach infected tissues compared to other methods of delivering antibiotics (systemic antibiotics are often inadequate for treating lower leg infections due to poor blood supply and insufficient synovial concentrations). This maximizes the effects of the antibiotics and decreases side effects associated with systemic antibiotic use.
RLP is easy to carry out (by a vet), can usually be carried out at the horse's home under a standing sedation, and should not be expensive.
RLP is used to treat and prevent lower limb infections e.g. bone infections such as osteomyelitis, septic joints or serious wounds.
A tourniquet is used above the infection site, and a high dose of antibiotics delivered into the blood supply below the tourniquet. Using a sufficient volume of antimicrobial perfusate may be important to increase the intravascular pressure and cause diffusion of the antibiotics into the tissues. The tourniquet may be left in place for 15 to 30 minutes. Several RLP treatments will usually be required - horses in clinics will usually have daily RLP. One clinic suggests carrying out RLPs once daily for three days, followed by RLP every other day for another two to four treatments in severe cases. RLP can also be carried out twice a day for severe cases. For milder cases, just one treatment may be sufficient, and treatment frequency should be guided by the original severity and response to treatment.
The antibiotic used must be safe to administer intravenously and be concentration dependent. Aminoglycosides such as Gentamicin, Amikacin and Ceftiofur are often appropriate and can be used for daily RLP, but many antimicrobials can be used. Bacterial culture can be used to guide the choice of antibiotics.
RLP may not be effective if the tourniquet pressure is not sufficient, the injection site is not well chosen, the dose of antibiotics used is insufficient, or if the horse moves (horses should be sedated for the procedure).
RLP can cause irritation and inflammation of and around the vein used.
Biasutti SA, Cox E, Jeffcott LB, Dart AJ
A review of regional limb perfusion for distal limb infections in the horse
Equine Veterinary Education May 2021 Vol 33 Issue 5 p 263-277. First published online January 2020. doi.org/10.1111/eve.13243
Regional limb perfusions - Stephanie Caston 2018
Kelmer G
Regional limb perfusion in horses
Vet Rec. June 2016 4;178(23):581-4. doi: 10.1136/vr.i3082 (Full paper on ResearchGate)
Subsolar Abscess and Coffin Bone Osteomyelitis - ACVS
How to perform a regional limb perfusion in horses - Amy Poulin Braim - DVM360 Mar 2015
Kelmer G, Bell GC, Martin-Jimenez T, Saxton AM, Catasus C, Elliot SB, Meibohm B.
Evaluation of regional limb perfusion with amikacin using the saphenous, cephalic, and palmar digital veins in standing horses.
J Vet Pharmacol Ther. 2013 Jun;36(3):236-40. doi: 10.1111/j.1365-2885.2012.01414.x. Epub 2012 May 18. PMID: 22607056.
Cimetti LJ, Merriam JG, D'Oench SN
How to Perform Intravenous Regional Limb Perfusion Using Amikacin and DMSO
AAEP Annual Convention 2004
1999 Vol. 45 AAEP PROCEEDINGS
How to Perform Regional Limb Perfusion in the Standing Horse
Scott E. Palmer, VMD; and Patricia M. Hogan, VMD
1998 Vol. 44 AAEP PROCEEDINGS
How to Perform Equine Intravenous Digital Perfusion
E. M. Santschi, DVM; S. B. Adams, DVM, MS; and E. D. Murphey, DVM
Resection - of hoof wall
Rucker A
Chronic laminitis: strategic hoof wall resection
Vet Clin North Am Equine Pract. 2010 Apr;26(1):197-205. doi: 10.1016/j.cveq.2009.12.009
Before considering a hoof wall resection, please read Dr Debra Taylor's presentation Laminitis Rehabilitation: If the corium is happy, there is hope. Have venograms taken, re-establish perfusion by minimizing mechanical compression and stretching of the corium within the hoof capsule. To reduce coronary corium compression, remove ground reaction force from the associated hoof wall at ground level, e.g. by beveling the hoof or dubbing the toe. Solar corium compression can be reduced by creating an air space beneath the rim of P3 (e.g. using thick pads inside hoof boots) and correcting the palmar angle. If this is insufficient to improve perfusion, higher level interventions to minimize compression may be considered, such as hoof grooving or partial hoof wall resection.
Rucker A
Chronic laminitis: strategic hoof wall resection
Vet Clin North Am Equine Pract. 2010 Apr;26(1):197-205. doi: 10.1016/j.cveq.2009.12.009
Before considering a hoof wall resection, please read Dr Debra Taylor's presentation Laminitis Rehabilitation: If the corium is happy, there is hope. Have venograms taken, re-establish perfusion by minimizing mechanical compression and stretching of the corium within the hoof capsule. To reduce coronary corium compression, remove ground reaction force from the associated hoof wall at ground level, e.g. by beveling the hoof or dubbing the toe. Solar corium compression can be reduced by creating an air space beneath the rim of P3 (e.g. using thick pads inside hoof boots) and correcting the palmar angle. If this is insufficient to improve perfusion, higher level interventions to minimize compression may be considered, such as hoof grooving or partial hoof wall resection.
Resveratrol
Manfredi JM, Stapley ED, Nadeau JA, Nash D
Investigation of the effects of a dietary supplement on insulin and adipokine concentrations in equine metabolic syndrome/
insulin dysregulation
Journal of Equine Veterinary Science published online Jan 2020. doi.org/10.1016/j.jevs.2020.102930
Resveratrol is a polyphenol. The objective of the study was to assess low and high dose administration of a synergistic polyphenol blend (SPB) plus leucine (SPB+L) supplement, which is presumably InsulinWise.
15 horses (Arabians and Morgans) with an average body condition score of 7/9, all previously diagnosed with insulin resistance by either FSIGTT or OST, were given either a low (750 mg resveratrol, 1150 mg leucine) or high (amounts not given) dose of the SPB+L in-feed supplement once a day for 6 weeks. There was no control group. All horses were fed a low NSC diet (average 11% NSC). Feed not detailed but included the same batch of hay before and throughout the study and a "small amount of nationally produced commercial grain".
An OST was carried out at the start and end of the study. In 10 out of the 15 horses, insulin concentrations decreased after the study, with no difference between high and low supplement dose. [Post-OST insulin has been shown to decrease with weight loss]. 5 horses (1/3) did not show improvements in insulin [did they lose weight during the study?]. Interestingly, insulin concentrations following supplementation were no different to insulin concentrations recorded 3 years previously (when horses had not received supplementation).
After the study horses showed significantly significant weight loss, which did not differ between high and low supplement dose. However, no significant changes in body condition score were recorded.
HMW adiponectin increased after the study, there was no significant difference between high and low supplement dose. [Adiponectin has been shown to increase with weight loss. However, note that around the time of the study, the validity of using HMW adiponectin, or at least some HMW adiponectin assays, was questioned - personal correspondence].
There were no significant differences between pre and post study concentrations of leptin, triglycerides, non-esterified fatty acids (NEFA) or TNF alpha.
Without controls, it cannot be known whether the horses lost weight because of their diet/management or whether the supplement had any effect, and TLS questions the authors' conclusion that "supplementation with a SPB+L supplement had positive impacts on metabolic parameters in EMS/ID horses". Giving the higher dose of supplement had no effect.
Note that this research was supported by Kentucky Performance Products, manufacturers of InsulinWise.
Non-Drug Treatments for Equine Metabolic Syndrome - Dr Vern Dryden & Dr Amanda Adams, www.thehorse.com 2018
Resveratrol - Equithrive
NB product claims that are not backed by published research are claims, not research.
Manfredi JM, Stapley ED, Nadeau JA, Nash D
Investigation of the effects of a dietary supplement on insulin and adipokine concentrations in equine metabolic syndrome/
insulin dysregulation
Journal of Equine Veterinary Science published online Jan 2020. doi.org/10.1016/j.jevs.2020.102930
Resveratrol is a polyphenol. The objective of the study was to assess low and high dose administration of a synergistic polyphenol blend (SPB) plus leucine (SPB+L) supplement, which is presumably InsulinWise.
15 horses (Arabians and Morgans) with an average body condition score of 7/9, all previously diagnosed with insulin resistance by either FSIGTT or OST, were given either a low (750 mg resveratrol, 1150 mg leucine) or high (amounts not given) dose of the SPB+L in-feed supplement once a day for 6 weeks. There was no control group. All horses were fed a low NSC diet (average 11% NSC). Feed not detailed but included the same batch of hay before and throughout the study and a "small amount of nationally produced commercial grain".
An OST was carried out at the start and end of the study. In 10 out of the 15 horses, insulin concentrations decreased after the study, with no difference between high and low supplement dose. [Post-OST insulin has been shown to decrease with weight loss]. 5 horses (1/3) did not show improvements in insulin [did they lose weight during the study?]. Interestingly, insulin concentrations following supplementation were no different to insulin concentrations recorded 3 years previously (when horses had not received supplementation).
After the study horses showed significantly significant weight loss, which did not differ between high and low supplement dose. However, no significant changes in body condition score were recorded.
HMW adiponectin increased after the study, there was no significant difference between high and low supplement dose. [Adiponectin has been shown to increase with weight loss. However, note that around the time of the study, the validity of using HMW adiponectin, or at least some HMW adiponectin assays, was questioned - personal correspondence].
There were no significant differences between pre and post study concentrations of leptin, triglycerides, non-esterified fatty acids (NEFA) or TNF alpha.
Without controls, it cannot be known whether the horses lost weight because of their diet/management or whether the supplement had any effect, and TLS questions the authors' conclusion that "supplementation with a SPB+L supplement had positive impacts on metabolic parameters in EMS/ID horses". Giving the higher dose of supplement had no effect.
Note that this research was supported by Kentucky Performance Products, manufacturers of InsulinWise.
Non-Drug Treatments for Equine Metabolic Syndrome - Dr Vern Dryden & Dr Amanda Adams, www.thehorse.com 2018
Resveratrol - Equithrive
NB product claims that are not backed by published research are claims, not research.
Retained placenta
Retention of any part of the placenta after foaling (or still birth) can lead to bacterial growth, inflammation and absorption of toxins, which can cause endotoxaemia, septicaemia, metritis, sepsis related laminitis (SRL) and death. Every part of the placenta should be removed, and the horse treated with systemic antibiotics and anti-inflammatories, and measures taken to prevent laminitis e.g. cyrotherapy.
Equine placenta – marvelous organ and a lethal weapon - Malgorzata Pozor (2013) - page 9 onwards
Current Therapy in Equine Reproduction - edited by Juan C. Samper, Jonathan F. Pycock, A. O. McKinnon (2007) p 465
Retention of any part of the placenta after foaling (or still birth) can lead to bacterial growth, inflammation and absorption of toxins, which can cause endotoxaemia, septicaemia, metritis, sepsis related laminitis (SRL) and death. Every part of the placenta should be removed, and the horse treated with systemic antibiotics and anti-inflammatories, and measures taken to prevent laminitis e.g. cyrotherapy.
Equine placenta – marvelous organ and a lethal weapon - Malgorzata Pozor (2013) - page 9 onwards
Current Therapy in Equine Reproduction - edited by Juan C. Samper, Jonathan F. Pycock, A. O. McKinnon (2007) p 465
RISQI
RISQI is the reciprocal of the square root of insulin, and represents the degree of insulin sensitivity (the higher the number, the more insulin sensitive).
RISQI is calculated: 1 divided by the square root of the baseline insulin result. So if a horse's fasting baseline insulin is 9 µIU/ml, the square root of 9 is 3, and 1/3 is 0.333. According to the Virginia Polytechnic research below, a RISQI of 0.333 would be normal, not IR. A fasting baseline insulin of 25 µIU/ml would give a RISQI of 0.20 (the square root of 25 is 5, 1/5 = 0.2), which according to the Virginia Polytechnic research below would indicate a high laminitis risk.
The use of the RISQI is not recommended by some vets - see Proxies and forum.
IR calculator - enter your horse's glucose and insulin blood results and the G:I ratio, RISQI, MIRG and IR status is calculated for you.
Virginia Polytechnic RISQI:
RISQI > 0.32 = normal
RISQI < 0.32 = laminitis risk
RISQI < 0.22 = high laminitis risk
RISQI is calculated: 1 divided by the square root of the baseline insulin result. So if a horse's fasting baseline insulin is 9 µIU/ml, the square root of 9 is 3, and 1/3 is 0.333. According to the Virginia Polytechnic research below, a RISQI of 0.333 would be normal, not IR. A fasting baseline insulin of 25 µIU/ml would give a RISQI of 0.20 (the square root of 25 is 5, 1/5 = 0.2), which according to the Virginia Polytechnic research below would indicate a high laminitis risk.
The use of the RISQI is not recommended by some vets - see Proxies and forum.
IR calculator - enter your horse's glucose and insulin blood results and the G:I ratio, RISQI, MIRG and IR status is calculated for you.
Virginia Polytechnic RISQI:
RISQI > 0.32 = normal
RISQI < 0.32 = laminitis risk
RISQI < 0.22 = high laminitis risk