MEASUREMENTS OF HEART SCORES AND HEART WEIGHTS IN HORSES OF 2 DIFFERENT MORPHIC BODY TYPES

Heart scores (the arithmetic mean of the QRS durations of the three bi polar limb leads for 10 cycles) and heart weights were determined from five draft type horses and five racing type horses, and evaluated for relationships between heart score and heart size within and between t he two different types of horses. Horses were killed using a captive b olt gun, and actual heart weights were recorded using an electronic di gital scale. The linear regression equation for heart weight versus he art score had a significant (P < 0.05) negative slope for racing types . The regression coefficients for heart weight versus heart score for draft types were not significantly (P > 0.05) different than zero. The re was no significant (P > 0.05) difference found between draft and ra cing types. Significant (P < 0.01) differences were found between the heart ratios (heart weight as a percentage of live body weight) of rac ing and draft types. Heart scores were not found to be significantly ( P > 0.05) different between racing and draft type horses.