LAMENESS IN 3-YEAR-OLD STANDARD-BRED TROTTERS - INFLUENCE OF PARAMETERS DETERMINED BEFORE 3 YEARS OF AGE

The aim of the study was to use available information about a group of Standardbred trotters collected during the first three years of life to predict the risk of lameness in these horses when they reach three years of age, In a previous study on the same population, a sire index defined as the frequency of lameness within each progeny group and pr esence of radiographic changes other than palmar/plantar bony fragment s in the metacarpo- and metatarsophalangeal joints, were found to be s ignificant predictors of the likelihood of developing lameness. The ad ditional variables used in the present study were training and feeding of the horses, information that was collected retrospectively up to t he time of clinical examination. A total of 265 three-year-old Standar dbred trotters were randomly sampled for an epidemiological study of l ameness. Eighty horses were classified as sound and 185 horses as lame , with moderate and severe signs in 138 and 47 horses, respectively. T he sire index was found to be significant for predicting lameness (P<0 .01), the risk of lameness increasing approximately 2.0 times for ever y 10% increase in sire index. Training and dietary parameters did not influence the risk of lameness significantly.