The cardiovascular capacity of turkeys is considerably affected by the selection procedure for meat production. To determine the body weight-related changes of some quantitative characteristics of the turkey heart function, serial measurements were carried out. BUT Big 6 turkeys (both sexes) were examined using whole-body magnetic resonance imaging (MRI) and spiral computer tomography (CT). Based on dynamic MRI examinations the following significant age- and sex-dependent quantitative differences were found. Means of the left ventricular stroke volumes were measured at the ages of 12 wk (males, 4.18 mL; females 2.89 mL), 16 wk (males, 6.56 mL; females, 4.14 mL), and 20 wk (males, 8.17 mL; females, 5.16 mL). Average cardiac output (CO) values were 0.76, 1.14, and 1.33 L/min for males and 0.58, 0.79,0.93 L/min for females. A statistically unproven age-dependent increasing tendency in the estimated relative CO value (skeletal muscle tissue volume measured by CT/CO unit) of male and female turkeys was found under sedentary conditions. These changes in the relative CO value and also the determined decrease of CO value related to body surface may, in theory, indicate a disadvantageous process that is more pronounced in males. The combined application of CT and MRI can be a powerful approach for studying the relationship between skeletal muscle development and heart capacity.

A two-way selection procedure was performed on a Landrace pig line. First the cardiac output (CO) values (6.89 ± 1.27 L/min) were estimated by ECGgated magnetic resonance imaging (MRI) to quantify the heart performance of the boars (n = 30), then total body skeletal muscle volume (MVTB; 48.7 ± 5.17 dm³) was determined applying spiral computerised tomography (CT). The relative cardiac output value (RCO) was developed, expressing the relationship between CO and MVTB. Four superior [RCO value below 6.7 dm 3 / (L * min ), n = 7 and 23], respectively. Comparing the existing five progeny groups, all of the 'HP+' groups differed significantly from the 'HP-' one, where the largest heart performance contrast found was 3.2 dm 3 / (L * min -1 ). Based upon the results, the selection is being continued on a larger population.