RESUMEN
Three hundred cattle from 12 dairy farms in Shiraz area were chosen randomly for population to be studied. After restraining, the jugular vein was examined for distention and on the base of severity, first, second and third degree distention was recorded. Then the cattle were checked for jugular pulsation. The data were analyzed by using Chi square, Fisher exact test and t-test. P < 0.05 was considered as significant. The prevalence of jugular distention [JD] and jugular pulsation [JP] were 13.3% +/- 3.3 and 9.77% +/- 3.8 in the population, respectively. The incidence of JD and JP was related to the amount of milk production, lactation period and systolic murmurs with the maximum intensity on the tricuspid valve. On the base of the results of this study it can be stated that although JD and JP are the signs of heart disorders but may also be observed in clinically healthy cattle. This study also indicated that there is a close association between the incidence of JD and JP with the amount of milk production and lactation period which can be concluded that milk production and lactation period may have effects on the cardiovascular system