CORONARY ARTERIOSCLEROSIS IN VEAL CALVES AND BEEF CATTLE: POTENTIAL RELATION TO HOUSING CONDITIONS

Arteriosclerosis, defined as chronic arterial change consisting of hardening, loss of elasticity and luminal narrowing, is greater in older animals. However, adverse socio-environmental factors have been reported to be a major stimulus to the development of arteriosclerosis of the intramural coronary arteries in young chicken (1), swine (2), mice (3) and monkeys (4). The present study aims to investigate the prevalence of coronary arteriosclerosis in regularly slaughtered veal calves and beef cattle. From January 2013 to March 2015 a systematic macroscopic and histological study of 42 bovine hearts was performed. Animals were 25, 6/9-months-old veal calves (60%) and 17, 10/24 months-old beef cattle (40%) housed in intensive livestock farming. Samples of interventricular septum, left and right papillary muscle, left and right ventricular free wall and left and right atrium were collected, fixed in 10% buffered formalin solution and paraffin embedded to obtain 5μm histological sections stained with Haematoxylin & Eosin, Weigert Van Gieson and Alcian Blue. Pathological intramural coronary arteries were manually counted in every localization. Data were compared by Kruskal-Wallis and Mann-Whitney U tests (GraphPad Prism R software, P value < 0.05). Selected paraffin embedded samples were also submitted to ultrastructural investigations. Arteriosclerosis of the intramural coronary arteries was observed in all calves and cattle (100%). Intimal hyperplasia, degenerative changes of the media tunica and medial hypertrophy/hyperplasia were the most important observed lesions. In calves there was a greater percentage of intimal hyperplasia (92% vs 88%) and degenerative changes of the media tunica (76% vs 71%). The medial hypertrophy/hyperplasia increased in cattle (59% vs 44%). This finding could reflect a temporal evolution of the arteriosclerotic disease. In calves the interventricular septum and the papillary muscles were significantly more affected (P < 0.0001), while in cattle the interventricular septum and the left papillary muscle only showed greater coronary arteriosclerosis (P < 0.0001). In cattle there was a greater percentage of stenotic intramural coronary arteries (45%) than in calves (23%), even if there was no significant difference between them (P > 0.05). Anitschkow cells, confirmed by ultrastructural investigations, were detected in both calves (60%) and cattle (76%). They were localized almost exclusively in coronary walls, suggesting a potential role in arteriosclerosis development. The preliminary results here described suggest a potential relationship between the development of coronary arteriosclerosis and intensive livestock farming of veal calves and beef cattle. A comparative study on free range cattle is in progress