The Detrimental Effects of Toe Grabs - Thoroughbred Racehorses at Risk

Presented by Bill CasnerApril 2007

Endorsed by: The Jockey Club, The Grayson-Jockey Club Research Foundation and The Kentucky Horseshoeing School

Kentucky Horseshoeing School

Photo by: Z

1. The Problem

2. Documented Contributors to Injury

Thoroughbred Anatomy

Toe Grabs

Thoroughbred Race Horse Anatomy

Age Bone structure is not completely matured in 2-5 year-olds Hoof is not completely matured

Pastern Length Long pasterns tend to facilitate underslung heels Underslung heels are correlated to decreased arterial blood

perfusion which effects growth rates of the heels Hoof TypeThin walls, lack of cartilage mass, smaller

hooves

Source: 2003. Contrasting structural morphologies of ‘good’ and ‘bad’ footed horses. Bowker, R.M. Proceedings 49th AAEP Convention, New Orleans, Louisiana

Scientific Research on Toe Grabs

Scientific studies conducted at top research centers show that toe grabs increase the risk of injury.

For example: 90.5% of horses experiencing catastrophic injuries wore toe grabs

Documented Research Results

Catastrophic injuries Toe grabs were present on 90.5% of horses Greater risk of catastrophic injury for long toe, underslung

foot types

Suspensory apparatus injuries 15.6% greater chance of suspensory apparatus failure with

toe grabs than without

Sources in order of use: 1996. Postmortem evaluation of homotypic variation in shoe characteristics of 201 Thoroughbred racehorses. Kane, A.J. et al. AJVR.57: 1141-1146.; 2001. Underrun heels and toe-grab length as possible risk factors for catastrophic musculoskeletal injuries in Oklahoma race horses. Balch, Olin k. et al. vol.47, AAEP proceedings; 2001.Risk factors for and outcomes of noncatastrophic suspensory apparatus injury in Thoroughbred racehorses. Hill AE, Stover GM, et al. JAVMA. 218: 1136-1144; 1996. Horsehoe characteristics as possible risk factors for fatal musculskeletal injury of Thoroughbred racehorses. Kane, A.J. et al. AJVR. 57:1147-1152

Documented Research Results (continued)

Harder racetrack surfaces are associated with increased risk for fatal injuries

$1 billion economic impact of musculoskeletal injuries in the Thoroughbred racehorses

Up to 83% of Thoroughbred racehorse deaths can be contributed to an exercise-related injury

Sources in order of use: 2001. Racehorse injuries, clinical problems and fatalities recorded on British racecourses from flat racing and National Hunt racing during 1996, 1997 and 1998. Williams, R.B. et al. Equine vet J. 33, 478-486; 1998. Epidemiologic studies of racehorse injuries. Kobluk, C.N. Current Techniques in Equine Surgery and Lameness, 2nd edn., Eds: N.A. White and J.M. Moore, W.B Saunderes Co. pp 564-569; 1994. Causes of death in racehorses over a 2 year period. Johnson, B. J. et al. Equine vet. J. 26, 327-330

What are the odds?

The odds of catastrophic injury in racehorses shod with toe grabs on front shoes is 1.5 times the odds in horses shod without toe grabs.

Source: 2004. Evaluation of horseshoe characteristics and high speed exercise history as possible risk factors for catastrophic musculoskeletal injury in Thoroughbred racehorses. Jorge A. DVM, MPVM, PhD; Scollay, C. DVM, et al. AJVR. Vol 66, No. 8, pp 1314-1320

What are the odds?

For horses shod with low toe grabs compared to horses shod without toe grabs on front shoes:

Fatal musculoskeletal injury (FMI) 1.8x Suspensory apparatus failure (SAF) 6.5x Cannon bone condylar fracture (CDY) 7.0x

Source: 2004. Evaluation of horseshoe characteristics and high speed exercise history as possible risk factors for catastrophic musculoskeletal injury in Thoroughbred racehorses. Jorge A. DVM, MPVM, PhD; Scollay, C. DVM, et al. AJVR. Vol 66, No. 8, pp 1314-1320

What are the odds?

For horses shod with regular toe grabs compared to horses shod without toe grabs on front shoes:

Fatal musculoskeletal injury (FMI) 3.5x Suspensory apparatus failure (SAF) 15.6x Cannon bone condylar fracture (CDY) 17.1x

Source: 2004. Evaluation of horseshoe characteristics and high speed exercise history as possible risk factors for catastrophic musculoskeletal injury in Thoroughbred racehorses. Jorge A. DVM, MPVM, PhD; Scollay, C. DVM, et al. AJVR. Vol 66, No. 8, pp 1314-1320

3. The Mechanics of Toe Grabs

How do shoes with toe grabs affect foot function?

They result in a broken-back hoof pastern axis They increase the degree that the sole flattens They cause the hoof wall to distort more They facilitate under run heels They magnify the hyperextension of the fetlock

joint

Normal Hoof/Shoe Impact

The hoof approaches the track and begins to enter the surface

The hoof and leg slide forward The ankle and hoof load The toe holds its position and the heel

rises upward The toe breaks over and hoof leaves the

surface

THE PHASES OF THE STRIDE1. Ground contact2. Slide phase3. Loading phase4. Heel lift off5. Breakover

Source: 2007. “Abnormal Forces Associated with Toe Grab Horse Shoes”, Rob Gillette, DVM, MSE; Mick Peterson, Ph.D.; Raoul Reiser, Ph.D.

Ground contact SLIDE SLIDE Heel lift Breakover

12

3 45

Toe Grab Entrance

As the toe enters the surface, the toe caulk acts as a wall, compacting the surface material in front of it, impeding the slide phase

At the same time the hoof is compacting the surface material below it.

The distal leg continues its forward momentum.

Source: 2007. “Abnormal Forces Associated with Toe Grab Horse Shoes”, Rob Gillette, DVM, MSE; Mick Peterson, Ph.D.; Raoul Reiser, Ph.D.

CUSHION

BASE

Toe Grab Exit

The toe caulk is fixated within the compacted surface material.

This increases the forces needed for breakover and toe-off to occur

Source: 2007. “Abnormal Forces Associated with Toe Grab Horse Shoes”, Rob Gillette, DVM, MSE; Mick Peterson, Ph.D.; Raoul Reiser, Ph.D.

Loaded Leg Sequence Both pictures are of same foot loaded equally

300 lbs 300 lbs

5” 6”

1200 lbs 1200 lbs

4”3”

3” 1.5”

3000 lbs 3000 lbs

Sagital Section of Same Foot

300 lbs 300 lbs

What’s happening inside the hoof?

1200 lbs 1200 lbs

Notice how much more the sole flattens

Normal heel compression * Excessive heel compression *

3000 lbs 3000 lbs

Notice the degree of wall deformation

**

4. The Solution

Eliminate the use of toe grabs (Banned in California in April 2007)

Continue to fund quantifiable research in equine lameness

Require continuing education on shoeing and hoof care as well as certification for farriers

Encourage additional state racing commissions and racetracks to ban use of toe grabs

Special thanks to:

The Jockey Club, The Grayson-Jockey Club Research Foundation, The Kentucky Horseshoeing School and to the

Welfare and Safety of the Racehorse Summit’s Horseshoeing Task Force for providing the background and support for this presentation. Prepared by Mitch Taylor and Kimberly Brown.

Kentucky Horseshoeing School