Dr Alison Harvey

 To investigate the impact of age and inferred prior vaccination history on the persistence of vaccine-induced antibody against rabies in horses.  Serologic response evaluation.  48 horses with an undocumented vaccination history.  Horses were vaccinated against rabies once. Blood samples were collected prior to vaccination, 3 to 7 weeks after vaccination, and at 6-month intervals for 2 to 3 years. Serum rabies virus–neutralizing antibody (RVNA) values were measured. An RVNA value of ≥ 0.5 U/mL was used to define a predicted protective immune response on the basis of World Health Organization recommendations for humans. Values were compared between horses < 20 and ≥ 20 years of age and between horses inferred to have been previously vaccinated and those inferred to be immunologically naïve.  A protective RVNA value (≥ 0.5 U/mL) was maintained for 2 to 3 years in horses inferred to have been previously vaccinated on the basis of prevaccination RVNA values. No significant difference was evident in response to rabies vaccination or duration of protective RVNA values between horses < 20 and ≥ 20 years of age. Seven horses were poor responders to vaccination. Significant differences were identified between horses inferred to have been previously vaccinated and horses inferred to be naïve prior to the study.  A rabies vaccination interval > 1 year may be appropriate for previously vaccinated horses but not for horses vaccinated only once. Additional research is required to confirm this finding and characterize the optimal primary dose series for rabies vaccination.

This study aimed to assess the effect of lateral heel studs on foot–ground interaction in the horse by quantifying foot slip during stance whilst cantering on a grass surface. It was hypothesised that using studs would decrease foot slip distance on the ground conditions tested. Nine horses were ridden with and without a stud placed laterally in the shoe of each of the 4 feet. High speed video-analysis was used to track hoof markers and to provide data quantifying foot slip distance, slip duration and stance duration. Using studs resulted in a significant decrease in foot slip distance in all four limbs (all  values < 0.004). The magnitude of the difference in slip distance with and without studs was greatest in the trailing limbs. The results supported the hypothesis that using studs will decrease foot slip distance in horses cantering on a grass surface, and additionally, highlights that stud efficacy may vary between limbs. The decrease in slip distance with studs demonstrated increased traction and a more stable foot–ground interaction, although this may cause a concomitant increase in the required energy dissipation, either within the limb or via surface deformation. The effect of repetitive usage of studs in the aetiology of musculoskeletal conditions should therefore be investigated further.