A field study on the efficacy of doramectin against strongyles and its egg reappearance period in horses.
The aim of the present study was to determine the efficacy and the so-called "egg reappearance period" (ERP) of doramectin in horses naturally infected with strongyles during a period of 34 weeks. A group of yearlings of 10 animals was treated intramuscularly with doramectin at a dose rate of 0.2 mg/kg bodyweight (BW) at the begin of the grazing season. To obtain comparable data, another group of yearlings (n = 10) was treated orally with ivermectin at a dose rate of 0.2 mg/kg BW. Individual faecal samples were examined for strongyle egg counts per gram of faeces (EPG) in two-week intervals. Twelve weeks later, a second treatment was given in both groups with the respective anthelmintic followed by a third treatment when the group mean egg count reached > or = 200 EPG. The efficacy of doramectin was > or = 96 % and that of ivermectin 100%, based on the mean egg counts two weeks post treatments (wpt). The highest and the lowest extensity of the efficacy (average values) for doramectin were 90% and 41% two and ten wpt, respectively, whereas these values for ivermectin differed from 100% (two wpt) to 24.3% (eight wpt). The ERP was found to be 10 and 8 weeks for doramectin and ivermectin, respectively.
Cirak
V Y
VY
Uludag University, Faculty of Veterinary Medicine, Parasitology Department, Gorukle Campus, Bursa, Turkey. vcirak@uludag.edu.tr
Güleğen
E
E
Yildirim
F
F
Durmaz
M
M
D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D005243:Feces / Q000469:parasitology; D006736:Horses; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D010270:Parasite Egg Count / Q000662:veterinary; D011897:Random Allocation; D013319:Strongyle Infections, Equine / Q000188:drug therapy*; D013323:Strongylus / Q000187:drug effects / Q000302:isolation & purification; D013997:Time Factors; D016896:Treatment Outcome
D000871:Anthelmintics; D007559:Ivermectin; C084101:doramectin