Prevalence and intensity of Oestrus ovis in sheep and goats in south-eastern part of Turkey

Oestrosis is a parasitic disease which is prevalent among sheep and goats in Mediterranean region. Slaughter house surveys to determine the prevalence and intensity of infestation by Oestrus ovis Linnaeus (Diptera: Oestridae) in sheep and goats, were conducted monthly for one year in south-eastern region of Turkey. A total of 804 heads belonging to 724 sheep and 80 goats were examined for Oestrus ovis larvae between May 2014 and April 2015. 72.75% of sheep heads and 50% of goat heads were seen to be infested with Oestrus ovis larvae. Of a total of 4723 larvae found in sheep heads, 2245 were detected to be first instars larva, 1231 second instars larva, 1247 third instars larva. Of a total of 259 larvae detected in goats, 150 were first instars larva, 79 second instars larva, 30 third instars larva. The mean of larval burden per infested animal was significantly higher in sheep (8.8±5.9) than in goat (6.5±5.0) (P < 0.05). Monthly distribution of first, second and third instars larvae indicate that adult flies are active between April and end of September, first instars larvae enter hypobiotic period in October. In conclusion, it was revealed that to use an effective drug against Oestrus ovis that will be done during reproductive period of flies should start in April and continue until the end of summer due to high rates of oestrosis, parasite treatment that will be done when reproductive period ends should be done in October and November in the southeast part of Turkey.