Study of ecological parameters on prevalence rate of hard tick in sheep in pastures of Sangsari tribe

To assess hard ticks population on Sangsari sheep breed under the effect of weather’s parameters such as duration of sun shine، humidity، ambient temperature، altitude، 5% of a flock (almost 1000 sheep in mountains and fields of Semnan and Tehran provinces) were randomly separated and were observed monthly. During a year، a total of 1505 hard ticks (635 females and 870 males) containing Dermacentor marginatus، Dermacentor raskemensis، Hyalomma marginatum marginatum were separated. Infestation rate were vary from 0% in two last months of autumn and winter to 82% in September. Intensity of infestation in different times، was vary from 0 to 12. 45 ticks on each sheep. Results showed that there is a significant relation between duration of sun shine and humidity with prevalence of infestations (p<0. 01). Average prevalence of infestation in different months was 56. 85% and average of intensity of infestations was 7. 56 ticks on each sheep. Also it was found out that altitude is one of the parameters which can affect the site of ticks on sheep’s body.