Study Looks At Shoes, Certain Injuries

This cross-sectional study examined horseshoes, exercise histories and moderate (non-fatal) suspensory injuries as possible risk factors for catastrophic suspensory apparatus failure (SAF) and condylar fracture of the distal canon bone (CDY). Comparisons were made between 108 horses with SAF, 33 with CDY and 160 control horses.

With slightly higher toe grabs on injured horses, only a marginal association was identified between toe grabs and moderate suspensory injury. However, the odds of SAF for horses shod with pads and horses with moderate suspensory injury were twice as high as for other horses. A longer interval since the last layup and higher intensity of recent exercise were also linked to SAF. Increased risk of CDY was associated with moderate suspensory injury, male horses, a longer interval since the last layup and higher intensity of recent exercise.

The authors conclude that while pads seem linked to SAF, the association may be attributed to another pre-existing injury for which the pads are a treatment rather than to a cause-and- effect relationship. They suggest the previously identified link between toe grabs and SAF and CDY may be partially attributed to the effects of exercise or pre-existing moderate suspensory injury. They suggest periodic reductions in exercise intensity for horses that have been in training for longer than 6 months could reduce the risk of catastrophic injury, particularly for those with moderate suspensory problems.

—Hill AE et al. AJVR 2004;65:1508-1517.

Horses Raised On Pasture Easier To Train

This experimental study examined the behavioral and physiologic effects of housing young horses in stalls versus on pasture during the initial stages of saddle training.

Sixteen Arabian horses (average age, 18.6 months) were divided into two groups housed on pasture or in stalls and were subjected to a typical ground work and saddle training regimen using a round pen approach. Heart rate, blood cortisol levels, time required to successfully complete a stage of training and behavioral responses were compared between groups.

Total training time was significantly longer for stalled horses compared with those kept on pasture. Stalled horses required more time to habituate to groundwork prior to mounting and the frequency of undesirable behavior was higher in stalled horses. Stalled horses extended their head and neck more often during riding and bucked and jumped more than pastured horses. Pastured horses tended to have slightly higher heart rates, but no differences in cortisol were detected between groups.

The authors conclude young horses kept on pasture adapt more easily to training than stalled horses.

—Rivera E. et al. Appl Anim Behav Sci 2002;78:235-252.

Study Examines Hoof Friction and Slippage

A laboratory study was conducted to estimate the coefficients of friction between hooves and five ground surfaces. 

Hoof sections cut parallel to the ground surface were fixed to a mechanical jig, the jig was loaded with weight and a transducer was used to measure the force required to slide the hooves across the surface being tested.

Estimates of the dynamic coefficients of friction were 0.28, 0.64, 0.71, 0.82 and 0.85 for steel, asphalt, concrete (patio stone), patterned rubber and smooth rubber, respectively. On the rubber surfaces, the force tracings were more variable with multiple small peaks in the dynamic range, indicating a “stick-slip” behavior.

The authors conclude slippage during locomotion most likely occurs during the first 25 milliseconds of contact with the ground. They also observed that although horseshoe nails may constrain hoof expansion at the ground surface in the quarters, hoof expansion behind the nails could be greater on steel compared to the other surfaces tested, because of steel’s lower coefficient of friction. They suggest there could be greater stress in the hoof wall behind the nails as the hoof expands more readily on top of steel.

—McClinchey HL et al. Biosystems Engineering 2004.

Massage Reduces Stress In Horses

The effects of massage on heart rate and behavior scores were examined in a study with 10 riding ponies and horses.

Massage treatments were applied in random order at six different sites. Heart rates were measured as an indicator of stress before, during and after treatments. Behavior was assessed during treatment using a scoring system indicating relaxation/pleasure or restlessness/irritation.

Massage of the withers, neck, croup and rump (both sides of the tail) resulted in decreased heart rates during and after the treatments compared with pretreatment values. No effect on heart rate was observed for massage of the forearm. Response to massage of the poll/ears was highly variable. Some animals resisted treatment and others showed a positive response that lasted for some time after treatment. Behavior scores indicated a positive response to massage at the withers, neck and croup with lower scores (negative) at the forearm, rump and poll/ears.

In part, the authors attributed the positive effects of massage to stimulation of acupressure points. They concluded massage at sites where horses habitually groom each other has a positive, calming effect on horses, reducing stress and resulting in relaxation. They suggest massage may be beneficial under certain low- to medium-stress situations such as isolation, veterinary procedures and by implication, shoeing.

 —McBride SD et al. J of Equine Vet Sci 2004;24:76-81.