The Relation of Egg Specific Gravity to the Incidence of Spontaneous Cardiomyopathy in Tom Turkeys

SUMMARY. The specific gravity and weight of eggs were determined for two groups of 600 eggs each, originating from Nicholas and British United Turkey of America (BUTA) turkey breeder flocks. A total of 137 Nicholas and 190 BUTA toms hatched from these eggs were used for the experiment. At days 21, 33, 40, 47, 56, and 61, toms that showed retarded growth were euthanatized, along with a corresponding number of normal birds. Both groups were measured for body weight, heart weight, separate weights of left and right ventricles, and combined atrial weight. At market age, the remaining toms were weighed, and the hearts were checked at processing for lesions characteristic of spontaneous turkey cardiomyopathy (STC). STC was found in 10.2% of Nicholas and 8.4% of BUTA toms. No correlation could be found between specific gravity of eggs and incidence of STC. Body weights of affected toms were reduced during the growing period. At processing, 2.8% of toms had lesions of STC, and mean body weight was 1298 g lower than average. The ratios of combined atrial weight: body weight, right ventricular weight: body weight, left ventricular weight: body weight, and total heart: body weight were significantly higher at all times in affected toms than in controls, and the differences were the greatest at 3 weeks of age.