Moxidectin is an anthelmintic agent used in horses for the control and treatment of various parasitic infections, particularly those caused by nematodes. It belongs to the macrocyclic lactone class of drugs and is known for its efficacy against a broad spectrum of parasites, including strongyles and bots. Moxidectin works by disrupting the nerve transmission in parasites, leading to paralysis and eventual death of the target organisms. Its pharmacokinetic properties allow for extended protection against re-infection, making it a valuable component in equine parasite management programs. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacodynamics, safety, efficacy, and resistance patterns associated with moxidectin use in horses.
Abbas G, Ghafar A, McConnell E, Beasley A, Bauquier J, Wilkes EJA, El-Hage C, Carrigan P, Cudmore L, Hurley J, Gauci CG, Beveridge I, Ling E....This study quantified the extent of anthelmintic resistance (AR) in ascarid and strongylid nematodes against commonly used anthelmintics in Australian Thoroughbred horses. Faecal egg count reduction tests (FECRTs, n = 86) and egg reappearance period (ERP) tests were conducted on 22 farms across Australia. Faecal egg counts (FECs) were determined using the modified McMaster technique, and percent faecal egg count reduction (%FECR) was calculated using the Bayesian hierarchical model and hybrid Frequentist/Bayesian analysis method. The results were interpreted using old (published in 1992) and...
Brys M, Claerebout E, Chiers K.The aim of this prospective, randomized, single-blinded, and placebo-controlled clinical trial was to investigate the efficacy of a moxidectin pour-on solution for the treatment of Chorioptes bovis infestation in Belgian draft horses, and in addition, to evaluate the effect of this treatment on the clinical signs and lesions associated with chronic progressive lymphedema (CPL). Nineteen privately owned Belgian draft horses were randomly assigned to either a treatment group (moxidectin pour-on formulation, n = 10) or a placebo group (phosphate-buffered saline (PBS), n = 9). On Day 0, all 19...
Prichard RK, Geary TG.Macrocyclic lactone (ML) anthelmintics are the most important class of anthelmintics because of our high dependence on them for the control of nematode parasites and some ectoparasites in livestock, companion animals and in humans. However, resistance to MLs is of increasing concern. Resistance is commonplace throughout the world in nematode parasites of small ruminants and is of increasing concern in horses, cattle, dogs and other animals. It is suspected in Onchocerca volvulus in humans. In most animals, resistance first arose to the avermectins, such as ivermectin (IVM), and subsequently to...
Molento MB, Canever RJ.Cyathostomins are the most prevalent nematodes of horses, and multidrug resistance has been reported worldwide. There is a need to implement alternative drug monitoring analytical tests. The objective of this study was to determine the consistency (5 repetitions) of the larval migration on agar test (LMAT) using ivermectin, moxidectin, pyrantel or albendazole against cyathostomin infective-stage larvae in eight different concentrations. LMAT showed a strong coefficient of determination (R2 > 0.91), between the test repetitions (n=5). The average 50% effective concentration (EC50) for iverme...
Lyons ET, Bellaw JL, Dorton AR, Tolliver SC.Field tests were performed on Thoroughbred yearlings (n=143), evaluating efficacy of moxidectin (MOX) against ascarids and strongyles and the efficacy of an ivermectin (IVM)-praziquantel (PRAZ) combination against those nematodes and tapeworms on a farm in Central Kentucky. The study was started on March 1, 2016 and completed on August 23, 2016. Fecal samples were collected from yearlings every two weeks for counts of ascarid and strongyle eggs per gram of feces (EPGs) and for determining the presence of tapeworm eggs. MOX was given to 88 yearlings on March 1; 55 yearlings were nontreated cont...
Tzelos T, Barbeito JS, Nielsen MK, Morgan ER, Hodgkinson JE, Matthews JB.Parasitic nematodes, particularly cyathostomins, are ubiquitous in grazing horses world-wide. Considerable burdens of cyathostomin larvae can encyst in the large intestinal wall. The most recommended treatment against these pathogenic stages is moxidectin. Information is required on how effective moxidectin is against cyathostomin populations in different regions. The objectives here were to determine the efficacy of moxidectin treatment and estimate the strongyle egg reappearance period (ERP) after treatment in several equine populations, to confirm the type of strongyle nematodes present and...
Saes IL, Vera JHS, Fachiolli DF, Yamada PH, Dellaqua JVT, Saes RL, Amarante AFT, Soutello RVG.The aim of this study was to determine the time required by different anthelmintic agents to reduce strongyle egg shedding in horses. Fifty horses were divided into five homogenous groups based on faecal egg counts (FECs). Treatment groups received either ivermectin; moxidectin; fenbendazole; piperazine; or no treatment (control group). Faecal examinations were performed 4, 8, 12, 18, 24, 36 and 48h after the anthelmintic treatment. After this period, faecal samples were taken every 24h over the next 12days and finally on alternate days (48-h intervals) for another 14days until the end of the ...
Kooyman FN, van Doorn DC, Geurden T, Mughini-Gras L, Ploeger HW, Wagenaar JA.For the control of cyathostomins in horses, the macrocyclic lactones (MLs), moxidectin (MOX) and ivermectin (IVM) are the most commonly used anthelmintics. However, reduced activity, observed as shortening of the egg reappearance period (ERP) has been described. Shortening of the ERP may be caused by a decreased susceptibility of immature worms for MLs. Alternatively, immature worms may develop faster into egg producing adults as a result of repeated ML treatments. The species composition of the larval cultures obtained shortly after ML and pyrantel (PYR) treatment can confirm the hypothesis o...
Bellaw JL, Pagan J, Cadell S, Phethean E, Donecker JM, Nielsen MK.Parasitic helminths of equids are capable of causing ill-thrift, clinical disease, and death. Although young horses are the most susceptible to parasitic disease and are the most intensively treated cohort, deworming regimens are rarely evaluated within this age group. This study objectively evaluated the impact of deworming regimen on fecal egg counts (FECs), growth rates, and body-condition scores in young Thoroughbreds. Forty-eight Thoroughbred foals from three central Kentucky farms were randomly allocated to two treatment groups: an interval dose program receiving bi-monthly rotations of ...
Reinemeyer CR, Prado JC, Nielsen MK.Despite widespread acknowledgement of cyathostomin resistance to adult icidal dosages of benzimidazole (BZD) anthelmintics, many strongyle control programs continue to feature regularly scheduled larvicidal treatment with fenbendazole (FBZ). However, no studies have been conducted to evaluate the efficacy of larvicidal regimens against encysted cyathostomins in a BZD-resistant (BZD-R) population. A masked, randomized, controlled clinical study was conducted with 18 juvenile horses harboring populations of cyathostomins that were considered BZD-R on the basis of fecal egg count reduction (FECR)...
Nielsen MK, Loynachan AT, Jacobsen S, Stewart JC, Reinemeyer CR, Horohov DW.Encysted cyathostomin larvae are ubiquitous in grazing horses. Arrested development occurs in this population and can lead to an accumulation of encysted larvae. Large numbers of tissue larvae place the horse at risk for developing larval cyathostominosis. This disease complex is caused by mass emergence of these larvae and is characterized by a generalized acute typhlocolitis and manifests itself as a profuse protein-losing watery diarrhea with a reported case-fatality rate of about 50%. Two anthelmintic formulations have a label claim for larvicidal therapy of these encysted stages; moxidect...
Mason ME, Voris ND, Ortis HA, Geeding AA, Kaplan RM.To compare larvicidal regimens of fenbendazole and moxidectin for reduction and suppression of cyathostomin fecal egg counts (FEC) in a transient herd of embryo transfer-recipient mares. Methods: Randomized, complete block, clinical trial. Methods: 120 mares from 21 states, residing on 1 farm. Methods: An initial fecal sample was collected from each mare; mares with an FEC ≥ 200 eggs/g were assigned to treatment groups. Eighty-two horses received fenbendazole (10.0 mg/kg [4.5 mg/lb], PO, q 24 h for 5 days) or moxidectin (0.4 mg/kg [0.18 mg/lb], PO, once); FEC data were analyzed 14, 45, and 9...
Geurden T, van Doorn D, Claerebout E, Kooyman F, De Keersmaecker S, Vercruysse J, Besognet B, Vanimisetti B, di Regalbono AF, Beraldo P, Di Cesare A....The objective of the present study was to evaluate the efficacy of an oral treatment with ivermectin (IVM) or moxidectin (MOX) against gastro-intestinal strongyles in naturally infected horses by performing a faecal egg count reduction test (FECRT) and by monitoring the egg reappearance period (ERP) after treatment. Therefore, a field efficacy study with a randomised complete block design for each study site was conducted, with the individual animal as the experimental unit. At least 10 study sites in Italy, Belgium and The Netherlands were selected and animals were allocated to one of the two...
Lyons ET, Tolliver SC, Kuzmina TA, Collins SS.Critical tests were performed in 2009 and 2010 in four 2-year-old horses naturally infected with internal parasites. The horses were from a herd (Farm MC) where reduced activity of ivermectin and moxidectin on small strongyles was demonstrated previously from EPG (eggs/gram of feces) data in field tests. Also, in critical tests in horses from the same herd, ivermectin was less effective on immature small strongyles in the lumen of the large intestine than when the drug was first marketed. The main interest in the present critical tests was to determine the efficacy of moxidectin (400 μg/kg) o...
Rossano MG, Smith AR, Lyons ET.Deworming horses with anthelmintics that have activity against encysted small strongyle larvae (L(3) and L(4)) is a common practice in parasite control programs. The two drugs currently available for this use are moxidectin (MOX) administered in a single dose of 0.4 mg/kg and fenbendazole (FBZ) given at the larvicidal dose (10mg/kg for 5 days). Here, we report the efficacy of MOX and the larvicidal dose of FBZ for reducing counts of strongyle-type eggs per gram of feces in naturally infected horses. Fecal egg counts (FECs) of 15 yearlings were observed following deworming. On day 0, 6 of the 1...
Rüfenacht S, Roosje PJ, Sager H, Doherr MG, Straub R, Goldinger-Müller P, Gerber V.Chorioptes bovis infestation is a common cause of pastern dermatitis in the horse, with a predilection in draft horses and other horses with thick hair 'feathers' on the distal limbs. The treatment of this superficial mite is challenging; treatment failure and relapse are common. Furthermore, C. bovis infestation may affect the progression of chronic pastern dermatitis (also known as chronic proliferative pastern dermatitis, chronic progressive lymphoedema and dermatitis verrucosa) in draft horses, manifesting with oedema, lichenification and excessive skin folds that can progress to verruci...
Cobb R, Boeckh A.This article reviews the current knowledge of the use of moxidectin (MOX) in horses, including its mode of action, pharmacokinetic and pharmacodynamic properties, efficacy, safety and resistance profile.Moxidectin is a second generation macrocyclic lactone (ML) with potent endectocide activity. It is used for parasite control in horses in an oral gel formulation. The principal mode of action of MOX and of other MLs is binding to gamma-aminobutyric (GABA) and glutamate-gated chloride channels. Moxidectin is different from other MLs in that it is a poor substrate for P-glycoproteins (P-gps) and ...
Traversa D, von Samson-Himmelstjerna G, Demeler J, Milillo P, Schürmann S, Barnes H, Otranto D, Perrucci S, di Regalbono AF, Beraldo P, Boeckh A....A large survey was carried out in 2008 in Europe to evaluate the efficacy of fenbendazole (FBZ), pyrantel (PYR), ivermectin (IVM) and moxidectin (MOX), i.e. the major anthelmintic molecules used in current practice against cyathostomins affecting horses. A total of 102 yards and 1704 horses was studied in three countries: 60 yards and 988 horses from Italy, 22 and 396 from the UK, 20 and 320 from Germany. The survey consisted of Faecal Egg Count Reduction Tests (FECRTs) with a faecal egg count reduction (FECR) categorization of (I) resistance present if FECR <90% and the lower 95% confidenc...
Schumacher J, Livesey L, DeGraves F, Blagburn B, Ziska S, Caldwell M, Brock K.This study was undertaken to determine whether resistance to moxidectin had developed in a large herd of draught horses, maintained on a small acreage, which had been routinely treated with moxidectin for five years. Faeces were collected for egg counts immediately before moxidectin gel was administered orally, and seven, 30, 60 and 90 days later. The faecal egg counts were significantly reduced at seven and 30 days after treatment, but were not significantly different from pretreatment counts at 60 and 90 days after treatment. There was no evidence of resistance having developed.
Slocombe JO, Coté JF, de Gannes RV.Three clinical trials with fecal egg count reduction tests and coproculture were conducted on 2 standardbred farms in Ontario. On Farm A, the treatment groups were mebendazole and ivermectin in trial 1, and fenbendazole and moxidectin in another. On Farm B, treatment groups were mebendazole and ivermectin. All horses treated with mebendazole or fenbendazole were subsequently treated with ivermectin or moxidectin. Strongyle eggs/g feces were estimated pre- and post-treatment using the Cornell-McMaster dilution and Cornell-Wisconsin centrifugal flotation techniques. After treatment, there was no...
Abbott JB, Mellor DJ, Love S.Serum protein electrophoresis (SPE) has previously been suggested as a means of assessing cyathostomin burdens in horses, although SPE used for that purpose is supported by little evidence. This clinical research report describes a study that objectively evaluated the use of SPE on a population of 38 horses following the administration of different anthelmintics. The population was subdivided into three groups, Groups F, M and P: 7.5 mg/kg bwt fenbendazole was administered to Group F on day -12; on day 0 0.4 mg/kg bwt moxidectin was administered to Group M and 19 mg/kg bwt pyrantel was adminis...
Lyons ET, Tolliver SC, Rathgeber RA, Collins SS.Foals (79), born in 2004 on three thoroughbred horse farms (C, M, and S) in central Kentucky, were fed pyrantel tartrate daily, beginning at about 3 months of age. In addition, other parasiticides [fenbendazole (FBZ), ivermectin (IVM) alone or with praziquantel (PRAZ), oxibendazole (OBZ), pyrantel pamoate (PRT), and moxidectin (MOX)] were given periodically. All treatments were administered by farm personnel. Over a 14-month period, from May 2004 to July 2005, collections (n=989) of feces were made from the foals for determination of presence of internal parasite eggs/oocysts by qualitative an...
Slocombe JO, de Gannes RV, Lake MC.The aims of studies in 2002 and 2003 on three farms with 76 foals naturally infected with Parascaris equorum were to (i) identify if the nematode was resistant to ivermectin and moxidectin, and (ii) confirm the effectiveness of fenbendazole and pyrantel pamoate for the parasite. Twelve clinical trials, each with a Fecal Egg Count Reduction Test, were conducted on two Thoroughbred and one Standardbred farms in southwestern Ontario, Canada. In each trial, Parascaris eggs/g feces were estimated for each foal pre- and post-treatment using the Cornell-Wisconsin double flotation and Cornell-McMaster...
Osman SA, Hanafy A, Amer SE.At Kafr El-Sheikh province, Egypt, out of 117 examined drafting horses, mites were detected in 20 (17.09%) horses. The recovered mites were 14 Chorioptes, four Psoroptes and two Sarcoptes whereas mites were not detected in four cases clinically showed typical mange lesions. Interestingly, neither the age nor the sex of the examined horses had a clear influence on the prevalence of the infection. Clinical signs observed in mange infested horses were in the form of irregular skin lesions, severe itching and sometimes biting of affected skin areas and decrease feed consumption. The skin lesions m...
Slocombe JO, de Gannes RV.Clinical trials using fecal egg count reduction tests and coproculture were conducted with yearlings and mares on a farm in 1997. Fecal samples were taken from each horse to estimate the number of strongyle eggs/g feces with Cornell-Wisconsin centrifugal flotation and Cornell-McMaster dilution techniques. Eleven of 15 yearlings, which had been on a daily feeding of grain with pyrantel tartrate for 66 d were found with strongyle eggs in feces. This was the first time the in-feed medication had been used on the farm. Nine yearlings were randomised into three groups; continuation of daily pyrante...
Lyons ET, Tolliver SC, Collins SS.Fecal samples (n=1,584) for a parasite study were collected from Thoroughbred foals (n=349), 28 to 330 days old, on seven farms in central Kentucky during 49 monthly trips from May to October, November, or December 2004. The main purpose was to determine possible drug resistance of ascarids, also of strongyles, to ivermectin (IVM) and other commercially available compounds [fenbendazole, moxidectin (MOX), oxibendazole (OBZ), and pyrantel pamoate]. In addition, interest was on prevalence of foal parasites. Qualitative data were obtained by recording presence or absence of ascarid and strongyle ...
Traversa D, von Samson-Himmelstjerna G, Demeler J, Milillo P, Schürmann S, Barnes H, Otranto D, Perrucci S, di Regalbono AF, Beraldo P, Boeckh A....A large survey was carried out in 2008 in Europe to evaluate the efficacy of fenbendazole (FBZ), pyrantel (PYR), ivermectin (IVM) and moxidectin (MOX), i.e. the major anthelmintic molecules used in current practice against cyathostomins affecting horses. A total of 102 yards and 1704 horses was studied in three countries: 60 yards and 988 horses from Italy, 22 and 396 from the UK, 20 and 320 from Germany. The survey consisted of Faecal Egg Count Reduction Tests (FECRTs) with a faecal egg count reduction (FECR) categorization of (I) resistance present if FECR <90% and the lower 95% confidenc...
Geurden T, van Doorn D, Claerebout E, Kooyman F, De Keersmaecker S, Vercruysse J, Besognet B, Vanimisetti B, di Regalbono AF, Beraldo P, Di Cesare A....The objective of the present study was to evaluate the efficacy of an oral treatment with ivermectin (IVM) or moxidectin (MOX) against gastro-intestinal strongyles in naturally infected horses by performing a faecal egg count reduction test (FECRT) and by monitoring the egg reappearance period (ERP) after treatment. Therefore, a field efficacy study with a randomised complete block design for each study site was conducted, with the individual animal as the experimental unit. At least 10 study sites in Italy, Belgium and The Netherlands were selected and animals were allocated to one of the two...
Tzelos T, Barbeito JS, Nielsen MK, Morgan ER, Hodgkinson JE, Matthews JB.Parasitic nematodes, particularly cyathostomins, are ubiquitous in grazing horses world-wide. Considerable burdens of cyathostomin larvae can encyst in the large intestinal wall. The most recommended treatment against these pathogenic stages is moxidectin. Information is required on how effective moxidectin is against cyathostomin populations in different regions. The objectives here were to determine the efficacy of moxidectin treatment and estimate the strongyle egg reappearance period (ERP) after treatment in several equine populations, to confirm the type of strongyle nematodes present and...
Slocombe JO, de Gannes RV, Lake MC.The aims of studies in 2002 and 2003 on three farms with 76 foals naturally infected with Parascaris equorum were to (i) identify if the nematode was resistant to ivermectin and moxidectin, and (ii) confirm the effectiveness of fenbendazole and pyrantel pamoate for the parasite. Twelve clinical trials, each with a Fecal Egg Count Reduction Test, were conducted on two Thoroughbred and one Standardbred farms in southwestern Ontario, Canada. In each trial, Parascaris eggs/g feces were estimated for each foal pre- and post-treatment using the Cornell-Wisconsin double flotation and Cornell-McMaster...
Xiao L, Herd RP, Majewski GA.Efficacies of moxidectin and ivermectin were compared in four groups of eight ponies with natural parasite infections: placebo (Control), oral moxidectin gel at 0.3 mg kg-1 of body weight (Mox 0.3), oral moxidectin gel at 0.4 mg kg-1 of body weight (Mox 0.4), and oral ivermectin paste at 0.2 mg kg-1 of body weight (Ivermectin). Fecal samples were taken 0 and 2 weeks after treatment. Animals were necropsied and worms were collected 2 weeks after treatment. Moxidectin and ivermectin showed similar efficacy (99%) against adult cyathostomes, Strongylus spp., Triodontophorus spp. and Habronema musc...
Cobb R, Boeckh A.This article reviews the current knowledge of the use of moxidectin (MOX) in horses, including its mode of action, pharmacokinetic and pharmacodynamic properties, efficacy, safety and resistance profile.Moxidectin is a second generation macrocyclic lactone (ML) with potent endectocide activity. It is used for parasite control in horses in an oral gel formulation. The principal mode of action of MOX and of other MLs is binding to gamma-aminobutyric (GABA) and glutamate-gated chloride channels. Moxidectin is different from other MLs in that it is a poor substrate for P-glycoproteins (P-gps) and ...
Lyons ET, Drudge JH, Tolliver SC.Over the past few years, cyathostomiasis has become increasingly recognized as a clinical problem of horses in the United States. Clinical cyathostomiasis has been reported frequently in Europe for a considerable time. This clinical syndrome is usually related to the sudden release of large numbers of the larval stages of small strongyles from the mucosa of the large intestine. Typical clinical signs include diarrhea, ventral abdominal edema, pyrexia, colic, weight loss, and poor body condition. Hypoalbuminemia and the presence of large numbers of small strongyles being passed in the feces are...
Monahan CM, Chapman MR, Taylor HW, French DD, Klei TR.Two dosages of moxidectin oral gel were evaluated and compared to a therapeutic dose of ivermectin oral paste in the control of a spectrum of gastrointestinal parasites of ponies naturally infected in southern Louisiana or Mississippi. Thirty-two mixed-breed ponies ranging in age from one to 21 years were used in this controlled test. Eight weeks prior to the experiment, ponies grazing on contaminated pasture were moved to a paddock and fed a pelleted ration, thus reducing or eliminating the potential for additional infection and ensuring the existence of a population of encysted larvae. Ponie...
Osman SA, Hanafy A, Amer SE.At Kafr El-Sheikh province, Egypt, out of 117 examined drafting horses, mites were detected in 20 (17.09%) horses. The recovered mites were 14 Chorioptes, four Psoroptes and two Sarcoptes whereas mites were not detected in four cases clinically showed typical mange lesions. Interestingly, neither the age nor the sex of the examined horses had a clear influence on the prevalence of the infection. Clinical signs observed in mange infested horses were in the form of irregular skin lesions, severe itching and sometimes biting of affected skin areas and decrease feed consumption. The skin lesions m...
Kooyman FN, van Doorn DC, Geurden T, Mughini-Gras L, Ploeger HW, Wagenaar JA.For the control of cyathostomins in horses, the macrocyclic lactones (MLs), moxidectin (MOX) and ivermectin (IVM) are the most commonly used anthelmintics. However, reduced activity, observed as shortening of the egg reappearance period (ERP) has been described. Shortening of the ERP may be caused by a decreased susceptibility of immature worms for MLs. Alternatively, immature worms may develop faster into egg producing adults as a result of repeated ML treatments. The species composition of the larval cultures obtained shortly after ML and pyrantel (PYR) treatment can confirm the hypothesis o...
Lyons ET, Tolliver SC, Collins SS.Fecal samples (n=1,584) for a parasite study were collected from Thoroughbred foals (n=349), 28 to 330 days old, on seven farms in central Kentucky during 49 monthly trips from May to October, November, or December 2004. The main purpose was to determine possible drug resistance of ascarids, also of strongyles, to ivermectin (IVM) and other commercially available compounds [fenbendazole, moxidectin (MOX), oxibendazole (OBZ), and pyrantel pamoate]. In addition, interest was on prevalence of foal parasites. Qualitative data were obtained by recording presence or absence of ascarid and strongyle ...
Rossano MG, Smith AR, Lyons ET.Deworming horses with anthelmintics that have activity against encysted small strongyle larvae (L(3) and L(4)) is a common practice in parasite control programs. The two drugs currently available for this use are moxidectin (MOX) administered in a single dose of 0.4 mg/kg and fenbendazole (FBZ) given at the larvicidal dose (10mg/kg for 5 days). Here, we report the efficacy of MOX and the larvicidal dose of FBZ for reducing counts of strongyle-type eggs per gram of feces in naturally infected horses. Fecal egg counts (FECs) of 15 yearlings were observed following deworming. On day 0, 6 of the 1...
Lyons ET, Tolliver SC, Kuzmina TA, Collins SS.Critical tests were performed in 2009 and 2010 in four 2-year-old horses naturally infected with internal parasites. The horses were from a herd (Farm MC) where reduced activity of ivermectin and moxidectin on small strongyles was demonstrated previously from EPG (eggs/gram of feces) data in field tests. Also, in critical tests in horses from the same herd, ivermectin was less effective on immature small strongyles in the lumen of the large intestine than when the drug was first marketed. The main interest in the present critical tests was to determine the efficacy of moxidectin (400 μg/kg) o...
Rüfenacht S, Roosje PJ, Sager H, Doherr MG, Straub R, Goldinger-Müller P, Gerber V.Chorioptes bovis infestation is a common cause of pastern dermatitis in the horse, with a predilection in draft horses and other horses with thick hair 'feathers' on the distal limbs. The treatment of this superficial mite is challenging; treatment failure and relapse are common. Furthermore, C. bovis infestation may affect the progression of chronic pastern dermatitis (also known as chronic proliferative pastern dermatitis, chronic progressive lymphoedema and dermatitis verrucosa) in draft horses, manifesting with oedema, lichenification and excessive skin folds that can progress to verruci...
Mercier P, Chick B, Alves-Branco F, White CR.Eighty horses were involved in a comparative, controlled, and randomised field study conducted in Australia and Brazil. This study was undertaken to address the duration of efficacy (by faecal egg count reduction) of four anthelmintic pastes and to measure the time required between treatments on horses naturally infected by gastrointestinal nematodes. The treatment interval was based on the egg reappearance period (ERP), defined as "the period after treatment when horses have reached a positive egg count equal or superior to 200 eggs per gram (epg) of faeces". Horses were ranked according to p...
Slocombe JO, de Gannes RV.Clinical trials using fecal egg count reduction tests and coproculture were conducted with yearlings and mares on a farm in 1997. Fecal samples were taken from each horse to estimate the number of strongyle eggs/g feces with Cornell-Wisconsin centrifugal flotation and Cornell-McMaster dilution techniques. Eleven of 15 yearlings, which had been on a daily feeding of grain with pyrantel tartrate for 66 d were found with strongyle eggs in feces. This was the first time the in-feed medication had been used on the farm. Nine yearlings were randomised into three groups; continuation of daily pyrante...
Bellaw JL, Pagan J, Cadell S, Phethean E, Donecker JM, Nielsen MK.Parasitic helminths of equids are capable of causing ill-thrift, clinical disease, and death. Although young horses are the most susceptible to parasitic disease and are the most intensively treated cohort, deworming regimens are rarely evaluated within this age group. This study objectively evaluated the impact of deworming regimen on fecal egg counts (FECs), growth rates, and body-condition scores in young Thoroughbreds. Forty-eight Thoroughbred foals from three central Kentucky farms were randomly allocated to two treatment groups: an interval dose program receiving bi-monthly rotations of ...
Mancebo OA, Verdi JH, Bulman GM.On the basis of positive skin snips for Onchocerca cervicalis microfilariae (MF), 45 horses were chosen from 48 in a total of 257 screened on 12 locations in the northeast Province of Formosa (Argentina), and randomly assigned to two treatment groups of 20 horses each, and a nontreated control group of five horses. On Day 14 post-treatment (PT), skin snip samples in the ivermectin-treated (0.2 mg/kg) group were negative for normal viable microfilariae (MF), while horses in the control group maintained their pretreatment level of infection. On the same Day in the moxidectin-treated (0.4 mg/kg) ...
Reinemeyer CR, Prado JC, Nielsen MK.Despite widespread acknowledgement of cyathostomin resistance to adult icidal dosages of benzimidazole (BZD) anthelmintics, many strongyle control programs continue to feature regularly scheduled larvicidal treatment with fenbendazole (FBZ). However, no studies have been conducted to evaluate the efficacy of larvicidal regimens against encysted cyathostomins in a BZD-resistant (BZD-R) population. A masked, randomized, controlled clinical study was conducted with 18 juvenile horses harboring populations of cyathostomins that were considered BZD-R on the basis of fecal egg count reduction (FECR)...
Lyons ET, Tolliver SC, Drudge JH, Granstrom DE, Collins SS, Stamper S.The activity of moxidectin was evaluated in 1988 and 1989 against natural infections of internal parasites in 20 critical tests (n = 20 equids) and three controlled tests (n = 20 equids). Two formulations, injectable administered intramuscularly (i.m.) or intraorally (i.o.) and gel i.o., were given at dose rates of 0.2, 0.3 or 0.4 mg kg-1 body weight. For the critical tests (all three dose rates evaluated), removals of second instar Gasterophilus intestinalis were 93-100%, except (89%) for the injectable formulation (i.m.) at 0.2 mg kg-1. Removals of third instar G. intestinalis were 88-100% f...
Boersema JH, Eysker M, van der Aar WM.The reappearance of strongyle eggs in the faeces of horses treated with moxidectin (0.4 mg/kg of body weight) was compared with that in the faeces of horses treated with ivermectin (0.2 mg/kg of body weight). The study was performed from December 1995 till June 1996. Horses were infected naturally in the preceding grazing period. Two groups of 24 horses each were treated with moxidectin and ivermectin respectively at week 0. No side effects were seen after treatment. Horses were housed from week -1 till week 17. From week 17 onwards the horses were on pasture. Faecal samples were taken from ea...
Lyons ET, Bellaw JL, Dorton AR, Tolliver SC.Field tests were performed on Thoroughbred yearlings (n=143), evaluating efficacy of moxidectin (MOX) against ascarids and strongyles and the efficacy of an ivermectin (IVM)-praziquantel (PRAZ) combination against those nematodes and tapeworms on a farm in Central Kentucky. The study was started on March 1, 2016 and completed on August 23, 2016. Fecal samples were collected from yearlings every two weeks for counts of ascarid and strongyle eggs per gram of feces (EPGs) and for determining the presence of tapeworm eggs. MOX was given to 88 yearlings on March 1; 55 yearlings were nontreated cont...
Bairden K, Brown SR, McGoldrick J, Parker LD, Talty PJ.The efficacy of moxidectin 2 per cent equine gel against naturally acquired strongyle infections was assessed in 18 ponies which had grazed on contaminated pasture before being housed for eight weeks. Twenty-four hours before the treatment, two randomly selected ponies were euthanased and their worm burdens were determined. Eight of the remaining 16 ponies were treated with moxidectin 2 per cent gel while the other eight were given a placebo gel. Eight weeks later the 16 animals were necropsied and their worm burdens established. A 100 per cent efficacy was recorded against adult and lumenal L...
Saes IL, Vera JHS, Fachiolli DF, Yamada PH, Dellaqua JVT, Saes RL, Amarante AFT, Soutello RVG.The aim of this study was to determine the time required by different anthelmintic agents to reduce strongyle egg shedding in horses. Fifty horses were divided into five homogenous groups based on faecal egg counts (FECs). Treatment groups received either ivermectin; moxidectin; fenbendazole; piperazine; or no treatment (control group). Faecal examinations were performed 4, 8, 12, 18, 24, 36 and 48h after the anthelmintic treatment. After this period, faecal samples were taken every 24h over the next 12days and finally on alternate days (48-h intervals) for another 14days until the end of the ...
Khan SA, Kuster DA, Hansen SR.Moxidectin is a macrolide endectocide available as a 2% equine oral gel in the US. This report presents clinical signs of moxidectin toxicosis and its treatment in equines as reported to the ASPCA Animal Poison Control Center (APCC) from January 1998 to December 2000. Nine cases of moxidectin overdose in equines occurred: 5 had signs of toxicosis such as coma, dyspnea, depression, ataxia, tremors, seizures, or weakness. The approximate dose of moxidectin at which these signs were observed ranged from 1.0 to 5.1 mg/kg. The 4 equines that ingested moxidectin between 0.9 mg/kg to 1.7 mg/kg did no...
Vercruysse J, Eysker M, Demeulenaere D, Smets K, Dorny P.A controlled trial was carried out to evaluate the persistence of the effect against small strongyles of a 2 per cent moxidectin gel administered orally to foals at a dose rate of 0.4 mg/kg bodyweight. Five of nine helminth-free foals were treated on day 0, and the remaining four foals were used as controls. On days 0, 7, 14, 21 and 28 all nine foals were infected experimentally with 200,000 small strongyle larvae. Three treated and two control foals were necropsied on day 42 and the rest on day 43. Fourteen species of small or medium sized small strongyles were found in the control foals, 10 ...
Rolfe PF, Dawson KL, Holm-Martin M.To compare the efficacy of moxidectin to ivermectin, oxibendazole and morantel against some gastrointestinal nematodes in horses. Methods: Faecal egg count reduction after treatment. Methods: A farm was selected where the population of small strongyles in horses was known to be resistant to oxibendazole. Horses were allocated to treatment groups based on faecal egg counts. After treatment, faecal samples were taken up to 109 days after treatment and faecal egg counts estimated. Faecal cultures were used to estimate the contribution of small and large strongyles to the faecal egg counts at each...
