Correlation between age of sheep and structural changes of sheep hydatid cyst

Backgroud: naturally, the prevalence of hydatid cyst of sheep increase with age and accompany with structural changes. objectives: the aim of the present study was to determine prevalence of hydatid cyst in sheep and its structure with age. methods: during 2009, 786 sheep in different age groups (1 to 6“ |years) slaughtered at babol abattoir, mazanderan province were examined for hydatid cyst infection through visual examination, palpation and slicing the infected organs into pieces. the number of cysts was counted and their mean volume, diameter, and number of protoscoleces in different age groups were determined. results: our findings showed the overall prevalence rate of infection 35.2%. there was a significant relation between age and considered parameters (p < 0.01). the viability of fertile cysts was 63-85%. the majority of cysts were detected through visual examination (86.4%) and the rest by palpation (8.5%) and slicing (5.1%). meanwhile 96% of protoscoleces were found in sheep older then 4 years of age. conclusions: old sheep are less productive, higher food consumers and harbor higher number of hydatid cysts. therefore it can be assumed that using an accurate method for detection of infected sheep in the herd, and culling and slaughterhng old infected sheep is a rather cheap and effective means to reduce the infection without losing a high proportion of sheep population.