effects of long-term calcium deficiency on the electro-and echocardiography in laying hens

background: ca is the most important minerals in the body that plays a key rols in the physiological activities, anzymatic reaction and the regulation of myocardial contraction and relax-ation. ca deficiency causes the heart failure and decrease cardiac contractility. objectives: to determine the effects of long-term dietary calcium deficiency on the heart function of layer hens based on the electro- and echocardiography. methods: ninety hyline w36 hens were kept for 21 weeks and fed by rations with different amounts of calcium. at 20, 28 and 36 weeks of age, electrocardio-graphic, echocardiographic and post-mortem left ventricular parameters were assessed. results: s wave amplitude was significantly (p