Benefits and risks of barefoot harness racing in Standardbred trotters

There is a lack of research on the benefits and risks of shoeing conditions in harness racing. Thus, our objectives were to: (a) investigate whether velocity times (VT; s/km) are affected by racing unshod (N = 76,932 records on 5,247 horses); (b) determine the potential risks of galloping, being penalized, and disqualification when competing unshod (N = 111,755 records on 6,423 horses); and (c) identify additional environmental factors that affect VT and risks. VT was found to be significantly influenced by shoeing condition (e.g., unshod, shod front, shod hind, or fully shod), but also by sex, age, season, track, track condition, start method, start position, distance, and driver‐horse performance level (p < 2e‐16). The risks of galloping and disqualification were significantly influenced by shoeing condition, sex, age, season, track, start method, start position, or driver‐horse performance level (p ≤ .05). Horses racing unshod had 0.7 s/km lower VT than fully shod horses and showed better performance when racing on neutral tracks during the late summer than horses with other shoeing conditions during the same period. However, racing unshod increased the relative risks of galloping and disqualification by 15%–35% in all seasons. Horses shod only on the hind hooves showed better performance than fully shod horses, without higher risks associated with competing unshod.     

A Cross-Sectional Survey of Forelimb Hoof Conformation and the Prevalence of Flat Feet in a Cohort of Thoroughbred Racehorses in New Zealand

Racehorses in New Zealand predominantly train counter clockwise. This training pattern has been associated with between forelimb differences in bone mineral density profile and asymmetrical limb loading after training. At present, there is limited data on the hoof conformation of these racehorses. Distal forelimb and digital hoof conformation data were collected from 75 Thoroughbred racehorses (2–5 years old) from two training yards. Digital conformation was subjectively graded, and multiple hoof measurements were made with a modified tire gauge (sole and sulci depth) and from digital photographs. All the horses were shod by two registered master farriers within a median of 15 (interquartile range [IQR], 1–25) days before measurement. There were few distal limb conformation abnormalities scored. Most (62/75) horses presented with some deviation from normal hoof parameters, with 2 (IQR, 1–3) abnormalities reported per horse. The most common hoof abnormality was uneven sulci, which was identified in 43 horses and 59 affected hooves, followed by higher medial hoof wall height in 38 horses and 53 affected hooves. Many of the linear and hoof angle measurements and their ratios were within the bounds reported within the literature and indicative of a balanced foot. The length and width measurements increased with horse age. The dorsal hoof wall (DHW) length:heel length ratios were consistently less than 3:1, and the absolute difference between toe and heel angle was generally greater than 5°. Between limb hoof variation was identified for a number of the morphologic measurements including frog length and sole length and the ratio of sole width:sole length. Flat feet (lack of concave solar surface) were identified in 21/75 (28%) horses and in 28/150 (19%) forelimb hoofs. More horses had a flat left foot (10/75) than right foot (4/75), but seven horses had both feet classified as being flat. Flat feet had 2.4 (1.1–5.6, P = .036) greater odds of presenting with uneven sulci. These data indicate that uneven sulci depth and flatter hooves with may be a typical presentation of Thoroughbred feet. Asymmetry in measurements between limb may reflect the greater loading of the left forelimb when race training counter clockwise.     

Measurement of vertical forces and temporal components of the strides of horses using instrumented shoes

Instrumented shoes were used to measure the vertical forces exerted by horses moving at a variety of gaits. Two types of shoes were used; one contained a single transducer positioned over the center of the frog and the second contained transducers located at the toe and both sides of the heel. Horses were shod with these instrumented shoes and walked and trotted over a force plate. Forces were simultaneously recorded from the transducers in the shoes and from the force plate. Comparisons were made between the amount and duration of the forces exerted on the transducers and the vertical and horizontal forces recorded from the force plate. Forces recorded from the single transducer shoes showed strong correlations with the forces recorded from the force plate for horses moving at the walk; however, at the trot only moderate correlations occurred between these forces. At both the walk and trot, forces recorded from each side of the heel and the total forces occurring on all three transducers from the front hooves of horses shod with three transducer shoes showed strong correlations to the vertical forces recorded from the force plate.Vertical forces were also recorded from the instrumented shoes as horses walked, trotted and galloped on a track straightaway. Forces recorded from normal horses shod with single transducer shoes on all four feet were greater on the forelimbs than the rear limbs at the walk and trot. At the gallop, forces were highest on the lead front followed by the nonlead front, lead rear and nonlead rearlimb, respectively. Forces recorded from a three transducer shoe on the right front hoof of a horse walking, trotting and galloping in a right lead were highest on the medial side of the heel and occurred during the middle of the support period. Peak forces on the toe occurred at or near the time of heel lift.The results of these studies indicate that these instrumented shoes have advantages over the methods previously used to measure locomotor forces. These instrumented shoes can be used to simultaneously record the temporal components and the amount and distribution of vertical forces exerted during consecutive strides of horses moving at a variety of gaits.     

Evaluation of an in-shoe pressure measurement system in horses

OBJECTIVE: To develop an objective, accurate method for quantifying forelimb ground reaction forces in horses by adapting a human in-shoe pressure measurement system and determine the reliability of the system for shod and unshod horses. ANIMALS: 6 adult Thoroughbreds. PROCEDURE: Horses were instrumented with a human in-shoe pressure measurement system and evaluated at a trot (3 m/s) on a motorized treadmill. Maximum force, stance time, and peak contact area were evaluated for shod and unshod horses. Three trials were performed for shod and unshod horses, and differences in the measured values were examined with a mixed model ANOVA for repeated measures. Sensor accuracy was evaluated by correlating measured variables to clinically observed lameness and by a variance component analysis. RESULTS: 4 of 6 horses were determined to be lame in a forelimb on the basis of clinical examination and measured values from the system. No significant differences were observed between shod and unshod horses for maximum force and stance time. A significant decrease in peak contact area was observed for shod and unshod horses at each successive trial. Maximum force measurements provided the highest correlation for detecting lameness (r = 0.91, shod horses; r = 1.0, unshod horses). A variance component analysis revealed that 3 trials provided a variance of 35.35 kg for maximum force (+/- 5.78% accuracy), 0.007 seconds for stance time (+/- 2.5% accuracy), and 8.58 cm2 for peak contact area (+/- 11.95% accuracy). CONCLUSIONS AND CLINICAL RELEVANCE: The in-shoe pressure measurement system provides an accurate, objective, and effective method to evaluate lameness in horses.     

A survey of white line disease in Japanese racehorses

A survey was carried out into white line disease in 1781 Thoroughbred racehorses kept in stables at the Japan Racing Association (JRA) Miho Training Center (MTC) September-October 1996. The survey was conducted while horses were being shod by farriers. The horses that still exhibited damaged white lines after regular trimming were diagnosed as having white line disease. The factors recorded were age, sex, number of diseased horses, number of diseased hooves, number of lesions by region over the bearing border of the hoof and the classified length of such lesions. The percentage of total diseased horses was 11.5% (204 animals), with incidence increasing significantly with age (P< or =0.01). Occurrence was independent of sex (P>0.05) was more frequent in the fore- than in the hindhoof and developed more frequently at the toe than at any other region of the forehoof-bearing border. Most lesions ranged from 20 to 30 mm in length.     

Retrospective study on 30 horses with chronic proliferative pododermatitis (canker)

The medical records of 30 horses (18 Warmbloods, 7 draught horses, 3 other breeds and 2 of unknown origin) with chronic proliferative pododermatitis (canker) were reviewed and long‐term outcome was obtained by telephone questionnaire. In 28/30 cases, the owner was the first to discover the problem. The disease was initially recognised as canker in only 5/28 cases, whereas in 10/28 cases a treatment for thrush had been continued for several months before referral. There was a similar prevalence in the fore (41) and hind (44) hooves; 13/30 horses had 4 hooves affected. Treatment consisted of surgical debridement and hoof care. Duration of hospitalisation was significantly decreased in horses receiving oral prednisolone for 3 weeks compared to those without this additional systemic treatment (mean ± s.d. 24 ± 5 days, n = 7 vs. 40 ± 19 days, n = 19, respectively). Long‐term follow‐up ranged from 3 months to 6 years (36 ± 22 months) and was available for 24 horses. No recurrence was reported in 10 horses. In 14 horses problems recurred within the first year, and 6 had been subjected to euthanasia for this reason specifically, whereas the others were managed by regular trimming. There was no significant association between recurrence and the number of affected hooves or the use of any systemic treatment. Horses with delayed referral because of preceding treatments had significantly more chance to develop recurrence, highlighting the need for prompt diagnosis and subsequent treatment.     

Effects of toe angle on hoof growth and contraction in the horse

The effects of toe angle on the growth of the unshod hooves of mature horses were measured over 126 days. The hooves of 4 horses were trimmed long in the toe and short in the heel (“LT”), with toe angles of 40° for the forelimb and 50° for the hind limb hooves; 4 others were trimmed short in the toe and long in the heel (“ST”), with toe angles of 50° for the forelimb and 55° for the hind limb hooves. Growth of the hoof wall at the toe ranged between .19 and .28 mm/day, and was slowest in the forelimb hooves trimmed ST. After 126 days, the hooves trimmed LT were 7% smaller in width than they had been at day 0. Narrowing of the hoof walls and frogs was accompanied by deformation of the angles of the walls (bending outward of their weightbearing surfaces). Frog lengths and sole areas were not affected by toe angle. Regardless of trimming method, all forelimb hooves tended to return to a toe angle of 45° between trimmings, while all hind limb hooves tended toward toe angles of 52° to 53°. The soles of all hooves were basically circular in shape, although the hooves trimmed LT tended to be skewed to the left, as viewed from above, after 126 days.     

Evaluation of platelet-rich plasma applied in the coronary band of healthy equine hooves

Platelet-rich plasma (PRP) is a widely used hemocomponent that holds great promise in equine medicine due to its feasible production and regenerative therapy potential. Its use has been considered as a treatment for chronic laminitis, mainly in terms of its analgesic properties and because it can induce growth in affected hooves. The aim of this study was to evaluate the effect on hoof growth attributable to PRP applied in the coronary band of clinically healthy horses by comparing the responses to PRP, saline, and trimming alone. After randomization, the forelimbs of 9 horses received specific treatment at intervals of 33 days and were trimmed, measured, and radiographed at the same time. Neither hoof growth nor hoof angles were different between the treatment groups at any time point. The application of PRP in the coronary band of horses may be a safe procedure; however, it had no effect on the growth or conformation of hooves in clinically healthy horses.     

Simultaneous detection of porcine circovirus type 2, classical swine fever virus,porcine parvovirus and porcine reproductive and respiratory syndrome virus in pigs by multiplex polymerase chain reaction

Results from a previous study indicated that there are specific arena surface characteristics that are associated with an increased likelihood of lameness in dressage horses. It is important to understand what modifiable arena factors lead to these detrimental surface characteristics. The aim of this study was to describe the use of training surfaces and arenas for United Kingdom dressage horses and to investigate any relationships between arena/surface variables and detrimental surface characteristics. Data from a questionnaire returned by 22.5% of all 11,363 registered members of British Dressage were used for the study. Univariate and multivariable logistic regression models were developed with each of the previously identified surface characteristics as dependent variables. Respondents reported that the majority of arenas were privately owned, sized 20 × 40 m and had a sand and rubber surface. The results indicated that wax-coated and sand and rubber surfaces were associated with less detrimental surface properties than sand, sand and PVC, woodchips or grass. Woodchips were most strongly associated with the detrimental characteristic of slipping, and sand with tripping. The findings indicated that any arena surface should have a base, with limestone the recommended surface, and that crushed concrete was best avoided. This information supported previous studies in racehorses that indicated that surface maintenance is essential, especially when many horses are using an arena daily. Problems were less likely if an arena was privately owned.     

Effects of lighting conditions on the welfare of horses being loaded for transportation

Horses are transported for a variety of purposes. Loading the horse onto a trailer or horsebox can be a source of stress and injury for both the horse and handler. This study investigated whether lighting conditions either inside or outside the trailer influence the welfare of horses during loading. Eight horses were initially trained to enter a trailer for a food reward, and were then loaded into an enclosed trailer either from a dark or lit arena and into a dark or lit trailer, in a replicated Latin Square design. Heart rate increased from the start to the end of each test in all treatments, suggesting that the horses experienced some fear of the loading process. However, there was no effect of lighting treatment on the increase in heart rate or the maximum or mean heart rates. Neither was there any effect of treatment on the speed of loading or number of refusals, which when examined with the heart rate data, suggests that there was no effect of lighting treatment on the horses’ fear of loading. However, horses loading from a lit arena were more likely to turn away from the trailer or lower their head than horses loading from a dark arena. In addition, those loading from a lit arena to a dark trailer sniffed the ground more, showing increased exploration of their environment. It is concluded that the amount of fear shown by horses was not affected by lighting conditions inside or outside the trailer, but there was some evidence of negative emotions when they loaded from a lit arena, particularly when they were entering a dark trailer.     

Relationships between hoof-acceleration patterns of galloping horses and dynamic properties of the track

OBJECTIVE: To define relationships between hoof-acceleration patterns of galloping horses and dynamic properties of the track. ANIMALS: 8 Thoroughbred horses without lameness. PROCEDURE: Acceleration-time curves were recorded by use of accelerometers attached to each hoof as each horse galloped over the track straightaway. Four sessions were conducted for each horse, with the track surface modified by sequentially adding water before each session. These acceleration-time curves were analyzed to determine peak accelerations during the support phase of the stride. Track dynamic properties (hardness, rebound, deceleration rate, rebound rate, and penetration) were recorded with a track-testing device. Moisture content and dry density were measured from soil samples. Stepwise multiple regression was used to identify relationships between hoof-acceleration variables and track dynamic properties. RESULTS: Track rebound rate was most consistently related to hoof variables, especially through an inverse relationship with negative acceleration peaks for all hooves. Also, rebound rate was related to initial acceleration peak during propulsion of the hooves of the forelimb and the nonlead hind limb as well as to the second acceleration peak during propulsion of the lead hooves of the hind limb and nonlead forelimb. CONCLUSIONS AND CLINICAL RELEVANCE: The inverse relationship between track rebound rate and negative acceleration peaks for all hooves reflects the most important dynamic property of a track. Any factor that reduces negative acceleration of the hooves will increase stride efficiency by allowing smoother transition from retardation to propulsion and therefore may be important in determining the safety of racing surfaces.     

Preliminary Examination of Farriery and Hoof Care Practices and Owner-Reported Injuries in Sport Horses in New Zealand

Retrospective management and owner-reported injury data, and measurement of forelimb hoof conformation, were collected via a cross-sectional survey from a convenience sample of 96 registered show jumping (n = 67) and dressage (n = 29) horses. Most of the horses were medium- to upper-level performers, aged 9 (interquartile range [IQR] 7–12) years, and in the current rider's ownership for 28 (IQR 12–60) months. The horses were trained 45 (IQR 35–60) minutes, 6 days per week, on a sand or sand mix arena. Failure to train for ≥7 days was reported in 26 of 96 horses, generally associated with lameness diagnosed by a veterinarian (16/29), with a median time-off of 26 (IQR 14–93) days. During the preceding 12 months, 33% of the riders had been working with the farrier on hoof-related issues, 30% of which had involved ≤2 issues. This remedial work often involved a veterinarian (14/30) or allied health practitioner (6/30). Most horses were hot shod (67/89) with conventional fullered shoes. Uneven feet were identified in 16 of 89 horses but were not positively associated with inability to train, possibly reflecting the minor variation between feet. Uneven feet were associated with variation in heel length and angle measurements and a greater sole length and reduced sole width, rather than smaller and boxy. Multiple correspondence plots identified an association of uneven feet with the dressage horses rather than show jumping horses.     

The art of horseshoeing--between empiricism and science

To correctly shoe a horse requires the farriers to have a good working knowledge of postural anomalies and movement patterns, as well as of the different concepts of horseshoeing and to be able to apply the appropriate technique to every individual horse they shoe. The correct technique for specific problem cases is frequently a subject of debate amongst specialists and many theories would benefit from objective gait analyses. The case study presented examines the influence of different shoeing conditions on selected gait analysis parameters. The measurements were conducted on a Warmblood mare: (A) shod with long toes, (B) properly trimmed without shoes, (C) conventionally shod with rolled toes and finally (D) shod using the 4-point technique. Data on force-, time- and distance parameters were recorded using an instrumented treadmill. First contact and breakover of the hooves were documented using high-speed videography. A long toe resulted in a prolongation of the breakover time and, therefore, in a prolongation of the second half of the stance phase. Additionally, the prolonged stance duration associated with an unaltered force impulse, led to decreased force peaks. It was possible to objectively record differences between the trimmed, unshod foot, the shod long-toe and the shod rolled toe configurations. The differences between the rolled toe and the 4 point shoe however, were minimal. Gait analysis is a technique well suited for objective evaluation of different shoeing techniques under standardised conditions.     

The origin and foot condition of horses slaughtered in Australia for the human consumption market

Reasons for performing study: There are ethical concerns regarding the loss of horses from various equine industries and their corresponding slaughter. However, to date, no empirical evidence regarding the extent of this loss, nor of the condition of horses involved, exists within Australia. Objectives: To determine the approximate ages, brand type and condition of feet of horses relinquished to an export abattoir in Australia. Method: Data were collected from 340 horses processed at an Australian abattoir from November 2007‐January 2008. Foot abnormalities, injuries and hoof indicators of overgrown and untrimmed hooves were assessed together with a dental inspection. Observations of brand were used to determine horse origin. Results: The dental age of 60% of horses was ≤7 years, and 53% originated from the racing industry (40% Thoroughbred and 13% Standardbred). A total of 81% of the horses had overgrown or untrimmed hooves. Standardbred horses had fewer grass cracks and more injuries to the coronary band than Thoroughbreds, probably due to pacing and trotting activities. Conclusions: Just over half of the horses slaughtered at an Australian abattoir on 3 working days were aged ≤7 years and emanated from the racing industry. Foot problems were common. Potential relevance: Future research should identify means of reducing the number of horses slaughtered and preventative measures for foot disorders.     

Use of a pressure plate to analyse the toe-heel load redistribution underneath a normal shoe and a shoe with a wide toe in sound warmblood horses at the walk and trot

The objective of this study was to use a pressure plate to quantify the toe-heel load redistribution in the forelimbs of sound warmblood horses with normal shoes and shoes with a wide toe and narrow branches, used empirically in the treatment of superficial digital flexor tendon or suspensory ligament injuries. In a crossover-design study, six horses, randomly shod with normal shoes and shoes with a wide toe, were led over a dynamically calibrated pressure plate to record data from both forelimbs. There were no significant differences between both shoes in the toe-heel index of stance time, peak vertical force and vertical impulse. For the adapted shoe, the peak vertical pressure was slightly lower and was exerted slightly earlier in the stance phase, albeit not significantly. However, the significantly larger toe contact area of the adapted shoe resulted in a significantly lower total vertical pressure in the toe region. Hence, the pressure plate adequately visualised the individual loading of the toe and heel region, and clearly demonstrated the altered pressure distribution underneath the shoe with a wide toe. Although further research on a deformable surface is needed to confirm this hypothesis, the pressure redistribution from the toe to the heels could promote sinking of the heels in arena footing, thereby mimicking the biomechanical effects of a toe wedge and providing a rationale for its application in the treatment of SDFT or SL injuries. The pressure measuring equipment used in this study can offer to the clinician a diagnostic tool for the evaluation of the load distribution underneath the equine hoof and for the fine-tuning of corrective shoeing.     

Long Toes in the Hind Feet and Pain in the Gluteal Region: An Observational Study of 77 Horses

This study deals with the relationship between long toes in the hind feet and pain in the gluteal region in horses, and the remedial value of trimming/shoeing that moves the breakover point back at the toe. Seventy seven client-owned horses were studied, 67 shod riding horses retrospectively and 10 barefoot broodmares prospectively. The 10 mares were evaluated twice, and 24 of the 67 riding horses were re-evaluated at the next shoeing, for a total of 111 observations. Each horse underwent gluteal palpation and lateral radiographs of both hind feet. Toe length was quantified as breakover distance (BD), the horizontal distance between the tip of the third phalanx and the dorsalmost point at which the wall/shoe was in contact with the ground. The BD was then shortened with trimming +/− shoeing to a length of ≤15mm (shod horses) or ≤20 mm (barefoot horses). The 24 riding horses were re-evaluated 4-6 weeks later and the 10 broodmares 1 week after trimming.     

Effect of dietary biotin supplement on equine hoof horn growth rate and hardness.

Over a 10-month period, 24 randomly selected riding horses were fed various amounts of biotin. Statistically significant improvements in growth rates and hardness of hooves were produced by biotin supplementation. Greater growth rates and hardness were achieved at a daily dose of 15 mg than at 7.5 mg. Increased hoof hardness was greatest in the hoof quarters and toe. No ring formation occurred in hooves of horses fed biotin intermittently.     

The effect of hoof trimming on radiographic measurements of the front feet of normal Warmblood horses

The understanding of the normal position of the third phalanx (P3) and the distal sesamoid bone in relation to the size and shape of the hoof capsule in sound horses is helpful in the diagnosis of equine foot lameness. Some measurements on radiographs used to define the position of the pedal bone within the hoof capsule are significantly influenced by hoof trimming and the height of the withers. In this study, the front hooves of 40 Warmblood horses were radiographed twice, eight weeks apart, both before and after their hooves were trimmed by an experienced farrier. Using the software programme Metron PX, 22 parameters on the lateromedial view and 16 parameters on the dorsopalmar view were measured and the effect of hoof trimming and height of the withers were calculated, respectively. Some of the hoof parameters showed mild positive correlation with the height of the withers. In 70% of the horses the left hoof capsule and P3 were significantly larger than the right. Hoof trimming had a remarkable influence on hoof conformation, especially for parameters in the toe region. Of all the measurements that describe the position of the third phalanx (P3) in relation to the hoof capsule, the distances between the distal tip of P3 to the solar surface of the foot, P3 to the tip of the toe and P3 to the point of break-over showed the greatest differences before and after trimming. The database of the present study can be used by farriers and veterinarians as a guideline for routine and corrective shoeing of Warmblood horses.