30 Veterinary Practitioner Vol. 14 No. 1 June 2013 THERAPEUTIC EFFICACY OF IVERMECTIN IN HELMINTHS INFESTED HORSES # J.P. Kachhawa 1 , A.P. Singh 2 , R.K. Dedar 3 , Subhash Kachhawaha 4 and N.K. Mudgal 5 Department of Clinical Veterinary Medicine, Ethics and Jurisprudence, College of Veterinary and Animal Science Rajasthan University of Veterinary and Animal Sciences, Bikaner-334001, Rajasthan, India ABSTRACT Two trials were conducted to evaluate the efficacy of ivermectin against gastrointestinal helminths of horses. In these trials, horses were treated with ivermectin orally and subcutaneously (10 horses for each trial) at 200 mcg per kg body weight once on Day 0. The horses carried naturally acquired parasite infestation as confirmed by pre-treatment faecal examination. The horses were re- examined for post-treatment faecal examination on Days 15. Horses treated with ivermectin significantly (P0.05) reduced the egg per gram (EPG) after treatment and exhibited high efficacy of ivermectin 98.42% orally and 97.83% subcutaneously against the gas- trointestinal helminths. Key words: EPG, helminths, horses and ivermectin 1 #Part of M.V.Sc. Thesis,Corresponding author and present address: Teaching Associate, TVCC, College of Veterinary and Animal Science, Bikaner (Rajasthan)-334001, Mobile: +919460062330, Email:jpkachhawa@gmail.com 2 Professor 3 Scientist, National Research Centre on Equine, Bikaner-334001, Rajasthan, India 4 Ph.D. scholar 5 M.V.Sc. Scholar Introduction Horses are important animals with multipurpose utility for draught, transport, sports, patrolling and traditional ceremonies. Horses play a very important role in the socio-economical life of the human population (Fazili and Kirmani, 2011). Parasitism in equines has been shown to be a major source of poor health resulting in considerable health problems, decreased draught power and performance. The species of helminths affecting horses is diverse, heavy and the parasites commonly encountered in equine faeces are Strongyles, Ascarids and Amphistomes (Ayele et al., 2006).The parasitic control measures recommended and practiced over the past decades seems to have provided limited protection to the horses because anthelmintic resistance has become increasing (Kaplan, 2004). The ivermectin was highly effective on gastrointestinal parasites in horses in the beginning. At that time, the counts of strongyle eggs per gram of faeces (EPGs) typically were negative or very low for about 8 weeks post-treatment for horses treated with ivermectin (Monahan and Klei, 2002). However, from other parts of world there are recent reports that egg reappearance periods (ERP) are declining for this drug, compared to when they first were marketed (Lyons et al., 2010; Traversa et al., 2009; Von Samson-Himmelstjerna, 2012). It is important in the veterinary field to re-evaluate, the efficacy of ivermectin in controlled studies, using sensitive examination procedures. Materials and Methods In the present investigation a total of 125 horses, irrespective of sex, age and breed were screened for faecal examination. These animals included from the horses brought to the Teaching Veterinary Clinical Complex of CVAS, nearby villages, as well as horses belonging to individual owners in and around Bikaner. Fresh faecal samples were collected from individual horses immediately after defaecation. The faecal examination was carried out to record the intensity of gastrointestinal helminths eggs in the known weight of the faecal sample. The intensity of infestation was calculated by counting the number of eggs per gram of faeces of individual horse. The intensity of gastrointestinal parasites eggs was recorded by modified McMaster technique as described by Coles et al. (1992). Based upon the results, the 20 horses were diagnosed positive for helminthiasis and these were classified in two groups Group-I and Group-II comprising of 10 animals in each. The treatment was administered immediately after completion of the faecal examination.Group-I animals were administered orally Ivermectin @ 200 μg/kg body weight as a single dose (Virbac, Animal Health India Pvt. Ltd., Bolus Hitek, each bolus contain 80 mg ivermectin). Group-II animals were administered injection Ivermectin @ 200 μg/kg body weight subcutaneously as a single dose (Intas Pharmaceuticals Ltd.), each ml contain 1% w/v ivermectin B.P. and excipients Q.S.). After administration of drug in each helminths positive animal, faecal sample were again collected on 15 th day for EPG count to note the efficacy of drug. The evaluation of Ivermectin efficacy of drug was done strictly on the basis of WAAVP guidelines as described by Wood et al. (1995) by comparing the mean EPG values before and after treatment. The data obtained in the research work undertaken were statistically analyzed and compared using standard formula given for mean, standard error and analysis of variance as per the procedures explained by Snedecor and Cochran (1994) and significance of mean difference were tested by Duncan’ new multiple range test (DNMRT).