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Steffen Rehbein - One of the best experts on this subject based on the ideXlab platform.
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the efficacy of eprinomectin extended release injection against naturally acquired nematode parasites of cattle with special regard to inhibited fourth stage ostertagia larvae
Veterinary Parasitology, 2013Co-Authors: James S Hunter, T A Yazwinski, S Yoon, J C Williams, Steffen RehbeinAbstract:Abstract The efficacy of eprinomectin in an extended-release injection (ERI) formulation in the treatment of cattle harboring naturally acquired nematode populations (including inhibited nematodes) was evaluated. Five studies were conducted under a similar protocol in the USA, the UK, and in Germany. All study animals were infected by grazing naturally contaminated pastures. The adequacy of pasture infectivity was confirmed by examining tracer calves prior to allocation and treatment of the study animals. The cattle were of various breeds or crosses, weighing 79–491 kg, and aged approximately 6–15 months. In each study, 20 animals were infected by grazing, and then removed from pasture and housed in a manner to preclude further nematode infections for 8–16 days until treatment. Animals were blocked based on descending pre-treatment body weight and randomly allocated to one of two treatments: ERI vehicle (control) at 1 mL/50 kg body weight or eprinomectin 5% (w/v) ERI at 1 mL/50 kg body weight (1.0 mg eprinomectin/kg). Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. For parasite recovery and count, all study animals were humanely euthanized 14/15 days after treatment. Cattle treated with eprinomectin ERI had significantly ( p Dictyocaulus viviparus, Capillaria spp., Cooperia oncophora , Cooperia pectinata , Cooperia punctata , Cooperia surnabada , Haemonchus placei , Nematodirus helvetianus , Oesophagostomum radiatum , Ostertagia lyrata , Ostertagia ostertagi , Trichostrongylus axei , Trichostrongylus colubriformis , Trichuris discolor , Trichuris skrjabini , and Trichuris spp.; developing fourth-stage larvae of Ostertagia spp. and Trichostrongylus spp.; and inhibited fourth-stage larvae of Cooperia spp., Haemonchus spp., Nematodirus spp., Oesophagostomum spp., Ostertagia spp., and Trichostrongylus spp. Animal treatments were well accepted, with no adverse reactions to treatment observed in any study animals. The results of this series of controlled studies demonstrated high therapeutic efficacy and acceptability of eprinomectin ERI against pulmonary nematodes and a wide range of gastrointestinal parasitic infections, including inhibited gastrointestinal nematodes, in cattle.
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Therapeutic efficacy of eprinomectin extended-release injection against induced infections of developing (fourth-stage larvae) and adult nematode parasites of cattle.
Veterinary parasitology, 2012Co-Authors: Steffen Rehbein, Dg Baggott, S Yoon, G.c. Royer, L.g. Cramer, Soll Mark DAbstract:Abstract The therapeutic efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against induced infections of developing fourth-stage larval or adult gastrointestinal and pulmonary nematodes of cattle in a series of six studies under two identical protocols (three each for developing fourth-stage larvae or adults) conducted in the USA, Germany or the UK (two studies at each location, one per stage). Each study initially included 16 nematode-free cattle. The cattle were of various breeds or crosses, weighed 109–186.5 kg prior to treatment, and were approximately 4–7 months old. The animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: eprinomectin ERI vehicle (control) at 1 mL/50 kg body weight or eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of eight and eight animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, cattle were infected with a combination of infective third-stage larvae or eggs of gastrointestinal and pulmonary nematodes. Inoculation was scheduled so that the nematodes were expected to be fourth-stage larvae or adults at the time of treatment. For parasite recovery, all study animals were humanely euthanized and necropsied 14–15 (adult infections) or 21–22 days after treatment (developing fourth-stage larval infections). When compared with the vehicle-treated control counts, efficacy of eprinomectin ERI against developing fourth-stage larvae and adults was ≥98% ( p Dictyocaulus viviparus , Bunostomum phlebotomum , Cooperia curticei , C. oncophora , C. surnabada , C. punctata , Haemonchus contortus , H. placei , Nematodirus helvetianus , Oesophagostomum radiatum , Oes. venulosum , Ostertagia leptospicularis , O. ostertagi , O. circumcincta , O. pinnata , O. trifurcata (developing fourth-stage larval infections only), Strongyloides papillosus , Trichostrongylus axei , T. colubriformis , and Trichuris ovis (adult infections only). All animals accepted the treatment well. No adverse reaction to treatments was observed in any animal in any study.
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Nematode burdens of pastured cattle treated once at turnout with eprinomectin extended-release injection.
Veterinary parasitology, 2012Co-Authors: Steffen Rehbein, T A Yazwinski, Bruce N. Kunkle, E. G. Johnson, Dg Baggott, S Yoon, L.g. Cramer, Soll Mark DAbstract:Abstract The efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against infections with third-stage larvae or eggs of gastrointestinal and pulmonary nematodes in cattle under 120-day natural challenge conditions in a series of five studies conducted in the USA (three studies) and in Europe (two studies). For each study, 30 nematode-free (four studies) or 30 cattle harboring naturally acquired nematode infections (one study) were included. The cattle were of various breeds or crosses, weighed 107.5–273 kg prior to treatment and aged approximately 4–11 months. For each study, animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: ERI vehicle (control) at 1 mL/50 kg bodyweight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of 15 and 15 animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, all animals grazed one naturally contaminated pasture for 120 days. At regular intervals during the studies, fecal samples from all cattle were examined for nematode egg and larval counts. In four studies pairs of tracer cattle were used to monitor pasture infectivity at 28-day intervals before and/or during the grazing period. All calves were weighed before turnout onto pasture and at regular intervals until housing on Day 120. For parasite recovery, all study animals were humanely euthanized 27–30 days after removal from pasture. Cattle treated with Eprinomectin ERI had significantly ( p p 92%: Dictyocaulus viviparus (adults and fourth-stage larvae (L4), Bunostomum phlebotomum , Cooperia curticei , Cooperia oncophora , Cooperia punctata , Cooperia surnabada , Cooperia spp. inhibited L4, Haemonchus contortus , Haemonchus placei , Haemonchus spp. inhibited L4, Nematodirus helvetianus , Nematodirus spp. inhibited L4, Oesophagostomum radiatum , Oesophagostomum spp. inhibited L4, Ostertagia leptospicularis , Ostertagia lyrata , Ostertagia ostertagi , Ostertagia spp. inhibited L4, Trichostrongylus axei , Trichostrongylus colubriformis , Trichostrongylus spp. inhibited L4, Trichuris discolor , and Trichuris ovis . Over the 120-day grazing period, Eprinomectin ERI-treated cattle gained between 4.8 kg and 31 kg more weight than the controls. This weight gain advantage was significant ( p All animals accepted the treatment well. No adverse reaction to treatment was observed in any animal in any study.
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Reevaluation of efficacy against nematode parasites and pharmacokinetics of topical eprinomectin in cattle
Parasitology Research, 2012Co-Authors: Steffen Rehbein, Martin Visser, Michael Kellermann, Laura LetendreAbstract:A study was conducted to confirm the efficacy of topical eprinomectin against nematodes and to evaluate the pharmacokinetics in cattle prevented from having physical contact with other cattle and from self-grooming. Sixteen male Brown Swiss calves were infected with larvae of recently isolated nematode parasites. Inoculation was scheduled so that the nematodes were expected to be adults at the time of treatment. Animals were blocked based on pretreatment body weight and randomly allocated to the untreated control group or the group treated with EPRINEX® Pour-On (Merial; 0.5 mg eprinomectin per kilogram body weight). Plasma samples were collected prior to and between 1 and 21 days following treatment and analysed for eprinomectin (B1a component) concentrations. For parasite recovery, identification and counting, animals were humanely euthanized 21 days after treatment. Calves treated with eprinomectin had significantly ( p 99 % reduction) adult Dictyocaulus viviparus , Bunostomum phlebotomum , Cooperia oncophora , Cooperia surnabada , Cooperia punctata , Nematodirus helvetianus , Oesophagostomum radiatum , Ostertagia ostertagi , Ostertagia lyrata , and Trichostrongylus axei and inhibited fourth-stage Nematodirus and Ostertagia larvae than the controls. The main pharmacokinetic parameters of eprinomectin B1a were: AUC(inf), 124 ± 24 day ng/mL; T _1/2, 5.2 ± 0.9 days; and C _max, 9.7 ± 2.2 ng/mL. Individual maximal concentrations were observed 3–7 days after treatment. This study confirmed the continued high level of efficacy of topically administered eprinomectin against a wide range of recently isolated nematodes. In addition, this study demonstrates that oral ingestion is not required to achieve adequate exposure for efficacy following topical administration of eprinomectin.
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Helminth infection in cattle from Schleswig-Holstein (Germany) after one grazing season
Berliner und Munchener tierarztliche Wochenschrift, 2003Co-Authors: Steffen Rehbein, Martin Visser, Renate WinterAbstract:Fifteen Holstein-Friesian bulls which grazed together for one season (April to November) in Schleswig-Holstein were necropsied after housing for 2 to 6 weeks. The approximately 12-month old bulls weighed 378 to 491 kg at slaughter and did not receive any anthelmintic on pasture. The most prevalent species of the gastrointestinal tract was Ostertagia ostertagi (prevalence; geometric mean worm count; minimum-maximum) (100%; 1,355; 130-4,590) followed by Cooperia (C.) oncophora (86.7%; 343; 20-14,800), Oesophagostomum (Oe.) radiatum (86.7%; 3.7; 1-42), Trichostrongylus axei (80%; 65; 50-910), C. punctata (73.3%; 14.8; 10-140), Trichuris (T.) discolor (73.3%; 4.8; 1-108) and Skrjabinagia lyrata (60%; 8.5; 18-260) which were recorded in more than half of the animals. Less frequently, C. surnabada (46.7%; 18; 10-4025), T. skrjabini (33.3%; 0.7; 2-14), Nematodirus helvetianus (13.3%; 0.5; 20-30), Spiculopteragia bohmi (6.7%; 0.2; [26]), Capillaria bovis (6.7%; 0.2; [10]) and Oe. venulosum (6.7%; 0.2; [9]) were recovered. Inhibited fourth-stage larvae of the Ostertagiinae were recovered from the abomasal mucosae of all bulls (100%; 13,159; 5,800-56,950). The abomasum harboured the highest worm burden followed by the small intestine and large intestine (geometric means): 15,565, 461 and 10 nematodes, respectively. Inhibited fourth-stage larvae amounted to 90% of the abomasal Ostertagiinae. Dictyocaulus viviparus was recorded in 73.3% of the animals with a geometric mean count of 12.8 (1-822 per animal).
Dg Baggott - One of the best experts on this subject based on the ideXlab platform.
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Therapeutic efficacy of eprinomectin extended-release injection against induced infections of developing (fourth-stage larvae) and adult nematode parasites of cattle.
Veterinary parasitology, 2012Co-Authors: Steffen Rehbein, Dg Baggott, S Yoon, G.c. Royer, L.g. Cramer, Soll Mark DAbstract:Abstract The therapeutic efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against induced infections of developing fourth-stage larval or adult gastrointestinal and pulmonary nematodes of cattle in a series of six studies under two identical protocols (three each for developing fourth-stage larvae or adults) conducted in the USA, Germany or the UK (two studies at each location, one per stage). Each study initially included 16 nematode-free cattle. The cattle were of various breeds or crosses, weighed 109–186.5 kg prior to treatment, and were approximately 4–7 months old. The animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: eprinomectin ERI vehicle (control) at 1 mL/50 kg body weight or eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of eight and eight animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, cattle were infected with a combination of infective third-stage larvae or eggs of gastrointestinal and pulmonary nematodes. Inoculation was scheduled so that the nematodes were expected to be fourth-stage larvae or adults at the time of treatment. For parasite recovery, all study animals were humanely euthanized and necropsied 14–15 (adult infections) or 21–22 days after treatment (developing fourth-stage larval infections). When compared with the vehicle-treated control counts, efficacy of eprinomectin ERI against developing fourth-stage larvae and adults was ≥98% ( p Dictyocaulus viviparus , Bunostomum phlebotomum , Cooperia curticei , C. oncophora , C. surnabada , C. punctata , Haemonchus contortus , H. placei , Nematodirus helvetianus , Oesophagostomum radiatum , Oes. venulosum , Ostertagia leptospicularis , O. ostertagi , O. circumcincta , O. pinnata , O. trifurcata (developing fourth-stage larval infections only), Strongyloides papillosus , Trichostrongylus axei , T. colubriformis , and Trichuris ovis (adult infections only). All animals accepted the treatment well. No adverse reaction to treatments was observed in any animal in any study.
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Nematode burdens of pastured cattle treated once at turnout with eprinomectin extended-release injection.
Veterinary parasitology, 2012Co-Authors: Steffen Rehbein, T A Yazwinski, Bruce N. Kunkle, E. G. Johnson, Dg Baggott, S Yoon, L.g. Cramer, Soll Mark DAbstract:Abstract The efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against infections with third-stage larvae or eggs of gastrointestinal and pulmonary nematodes in cattle under 120-day natural challenge conditions in a series of five studies conducted in the USA (three studies) and in Europe (two studies). For each study, 30 nematode-free (four studies) or 30 cattle harboring naturally acquired nematode infections (one study) were included. The cattle were of various breeds or crosses, weighed 107.5–273 kg prior to treatment and aged approximately 4–11 months. For each study, animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: ERI vehicle (control) at 1 mL/50 kg bodyweight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of 15 and 15 animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, all animals grazed one naturally contaminated pasture for 120 days. At regular intervals during the studies, fecal samples from all cattle were examined for nematode egg and larval counts. In four studies pairs of tracer cattle were used to monitor pasture infectivity at 28-day intervals before and/or during the grazing period. All calves were weighed before turnout onto pasture and at regular intervals until housing on Day 120. For parasite recovery, all study animals were humanely euthanized 27–30 days after removal from pasture. Cattle treated with Eprinomectin ERI had significantly ( p p 92%: Dictyocaulus viviparus (adults and fourth-stage larvae (L4), Bunostomum phlebotomum , Cooperia curticei , Cooperia oncophora , Cooperia punctata , Cooperia surnabada , Cooperia spp. inhibited L4, Haemonchus contortus , Haemonchus placei , Haemonchus spp. inhibited L4, Nematodirus helvetianus , Nematodirus spp. inhibited L4, Oesophagostomum radiatum , Oesophagostomum spp. inhibited L4, Ostertagia leptospicularis , Ostertagia lyrata , Ostertagia ostertagi , Ostertagia spp. inhibited L4, Trichostrongylus axei , Trichostrongylus colubriformis , Trichostrongylus spp. inhibited L4, Trichuris discolor , and Trichuris ovis . Over the 120-day grazing period, Eprinomectin ERI-treated cattle gained between 4.8 kg and 31 kg more weight than the controls. This weight gain advantage was significant ( p All animals accepted the treatment well. No adverse reaction to treatment was observed in any animal in any study.
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Nematode burdens and productivity of grazing cattle treated with a prototype sustained-release bolus containing ivermectin
The Veterinary record, 1994Co-Authors: Dg Baggott, Jm Preston, Db Ross, S. J. GrossAbstract:One hundred and twenty four-month-old Hereford-Friesian cross heifers weighing from 88 to 130 kg were divided into two equal groups. One group acted as a control with each animal receiving one placebo bolus, the other animals received one prototype intraruminal sustained-release bolus designed to deliver approximately 8 mg ivermectin/day for 100 to 120 days. The boluses were administered the day before turnout in mid-May. Each group was grazed separately for 167 days on pastures contaminated with parasitic nematode larvae including the lungworm Dictyocaulus viviparus, and the gastrointestinal worms Ostertagia ostertagi, Cooperia oncophora and Nematodirus helvetianus. Parasitic disease did not occur in the ivermectin-bolus group, but the control group required anthelmintic treatment to control parasitic gastroenteritis at 111 and 154 days after turnout. Up to the 111th day after turnout, the peak mean nematode egg and larval counts per gram of faeces in controls was, respectively, 564 epg and 0.5 lpg. Based on faecal nematode egg counts and worm burdens in bolus-treated cattle removed from pasture at 119 days after turnout and bolus function studies, it was concluded that ivermectin delivery from the prototype bolus ceased between 95 and 98 days after administration. However, unlike the controls, the treated cattle did not develop parasitic gastroenteritis at any time. Their faecal nematode egg output was significantly (P < 0.01) lower (< 1 epg) compared to the controls and lungworm larval output zero during the functional life of the bolus. The faecal egg and larval outputs continued low until the end of the trial.(ABSTRACT TRUNCATED AT 250 WORDS)
J.s. Eagleson - One of the best experts on this subject based on the ideXlab platform.
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the efficacy of eprinomectin against induced infections of immature fourth larval stage and adult nematode parasites in cattle
Veterinary Parasitology, 1997Co-Authors: S.r. Pitt, W.k. Langholff, J.s. Eagleson, Steffen RehbeinAbstract:Abstract Eprinomectin is a new endoctocide of the avermectin chemical group developed for use in cattle. To establish its effectiveness against Cooperia spp., Dictyocaulus viviparus, Haemonchus contortus, Nematodirus helvetianus, Oesophagostomum radiatum, Ostertagia ostertagi, Trichostrongylus axei and Trichostrongylus colubriformis (immature infections only), six trials were conducted in Europe at two trial sites. In each trial, animals were artificially infected with a number of nematode species and treated with eprinomectin. In three trials, the nematodes were expected to be at the fourth larval stage of development at the time of treatment, and at the adult stage at the time of treatment in the other three trials. When compared with the untreated control groups, efficacy against the adult and immature nematode infections was >99% for all the nematode species examined. There was no difference in efficacy between groups of animals with clipped hair at the application site, and those with long hair. Subsequent examination of the application sites, both visual and by palpation, showed no gross reactions to the applied treatments.
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effect of simulated rain coat length and exposure to natural climatic conditions on the efficacy of a topical formulation of eprinomectin against endoparasites of cattle
Veterinary Parasitology, 1997Co-Authors: R P Gogolewski, W.k Langholff, D.r. Thompson, G R Allerton, S R Pitt, J A Hair, R K Fulton, J.s. EaglesonAbstract:Abstract A series of five controlled studies involving 114 cattle were conducted in Australia, North America and the United Kingdom to examine the effect of simulated rain, coat length and exposure to natural climatic conditions, on the efficacy of a topical formulation of eprinomectin against nematode parasites of cattle. In all trials infections were induced with a range of bovine nematode species and treatment was applied when the majority of nematodes were mature. In one study, simulated rain was applied to cattle ending one hour before treatment or geginning one, three or six hours after treatment. In a second study cattle had short (1 cm) or long (3–6 cm) haircoats at the time of treatment. Three other studies were conducted usinv cattle housed indoors or exposed to various natural climatic conditions. Nematode counts were determined using standard techniques and the efficacy of treatment was assessed relative to vehicle-treated controls. Regardless of the timing of simulated rain relative to treatment, eprinomectin was at least 99.9% effective (p 0.10) in efficacy between treatment administered to dry or wet cattle, or treatment administered before or after simulated rainfall. Efficacies against O. ostertagi, T. axei, Cooperia oncophora and Dictyocaulus viviparus were >99.5% (p 0.10) with efficacies of greater than 99.5% being maintained against H. placei, O. ostertagi (adult and fourth-stage larvae), T. axei, Cooperia spp., Nematodirus helvetianus (adult and inhibited fourth-stage larvae) and Oesophagostomum radiatum. These findings indicate that eprinomectin (500 μg/kg) in a topical formulation is a safe and highly effective nematocide for cattle regardless of their coat length and this high level of efficacy is maintained in cattle exposed to a wide variety of climatic conditions.
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Nematocidal efficacy of eprinomectin, delivered topically, in naturally infected cattle.
American journal of veterinary research, 1997Co-Authors: T A Yazwinski, G.l. Zimmerman, W.k Langholff, J E Holste, E. G. Johnson, D.r. Thompson, M. D. Drag, J.s. EaglesonAbstract:OBJECTIVE To assess the nematocidal efficacy of eprinomectin in naturally infected cattle. ANIMALS 62 (31 eprinomectin-treated and 31 control) beef mixed-breed or Holstein cattle, either 6 to 11 or 48 to 96 months old. PROCEDURE Cattle were housed 21 to 27 days before treatment to allow parasites to reach maturity. Animals were grouped by sex, ranked by weight, and randomly assigned to treatment group. Fecal flotation was done to identify cattle with intestinal nematode infections. Treatment groups were: 1--eprinomectin topical vehicle (1 ml/10 kg) and 2--eprinomectin topical solution (1 ml/10 kg). Cattle were euthanatized by replicate on day 14 or 15, and standard procedures were used to recover of pulmonary, abomasal, small intestinal, and large intestinal nematodes. RESULTS Eprinomectin efficacy across all trials was 100% against adult Trichostrongylus axei, Haemonchus placei, Oesophagostomum radiatum, and Dictyocaulus viviparus, as well a fourth-stage larval Oes radiatum, Ostertagia ostertagi, Nematodirus helvetianus, and Cooperia spp. Efficacy against adult O ostertagi, Cooperia oncophora, C punctata, C surnabada, C spatulata, N helvetianus, Trichuris sp, and Trichuris fourth-stage larvae was 99.9 and 99.8, 99.6, 98.9, 98.3, 99.7, 97.8, and 84.3%, respectively. All results were significant (P < 0.01) except those for C spatulata. Adverse reactions were not observed. CONCLUSION AND CLINICAL RELEVANCE Eprinomectin is a safe and effective nematocide against naturally acquired nematode infections in cattle when administered at a dosage of 500 micrograms/kg. Milk and meat withholding is not necessary when using this product.
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Efficacy of injectable abamectin against gastrointestinal tract nematodes and lungworms of cattle
American journal of veterinary research, 1994Co-Authors: R.m. Kaplan, Charles H. Courtney, W.e. Kunkle, Q.y. Zeng, A.d. Jernigan, J.s. EaglesonAbstract:Efficacy of abamectin against gastrointestinal tract nematodes and lungworms of cattle was determined in 4 experiments. The first 2 experiments were controlled trials in which efficacy was determined at necropsy in calves with either experimentally induced (n = 14) or naturally acquired (n = 16) infections. Half the calves in each experiment were treated with abamectin (200 micrograms/kg of body weight, SC), and half were left untreated as controls. Efficacy was > 99% against adult stages of Dictyocaulus viviparus, Haemonchus placei, Ostertagia ostertagi, Trichostrongylus axei, Cooperia punctata, Trichuris discolor, and C oncophora, and was 92.4% against Nematodirus helvetianus. The second 2 experiments were clinical trials in which efficacy was determined by fecal egg count reduction in naturally infected yearling heifers (n = 75) or 2-year-old heifers (n = 75). Within replicates of 5, 4 heifers were assigned at random to treatment with 200 micrograms of abamectin/kg and 1 was left untreated as a control. Abamectin was 100% effective in eliminating strongylate nematode eggs from the feces of these heifers. In all experiments, adverse reactions were limited to small, clinically unimportant injection site swellings in 29% of abamectin-treated calves. Abamectin was judged to be safe and effective in these trials.
Robin B. Gasser - One of the best experts on this subject based on the ideXlab platform.
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Differences in the second internal transcribed spacer of four species of Nematodirus (Nematoda: Molineidae)☆
International Journal for Parasitology, 1998Co-Authors: Lisa A. Newton, Neil B Chilton, Ian Beveridge, Robin B. GasserAbstract:Abstract Genetic differences among Nematodirus spathiger, Nematodirus filicollis, Nematodirus helvetianus and Nematodirus battus in the nucleotide sequence of the second internal transcribed spacer (ITS-2) of ribosomal DNA ranged from 3.9 to 24.7%. Pairwise comparisons of their ITS-2 sequences indicated that the most genetically similar species were N. spathiger and N. helvetianus. N. battus was the most genetically distinct species, with differences ranging from 22.8 to 24.7% with respect to the other three species. Some of the nucleotide differences among species provided different endonuclease restriction sites that could be used in restriction fragment length polymorphism studies. The ITS-2 sequence data may prove useful in studies of the systematics of molineid nematodes.
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differences in the second internal transcribed spacer of four species of Nematodirus nematoda molineidae
International Journal for Parasitology, 1998Co-Authors: Lisa A. Newton, Neil B Chilton, Ian Beveridge, Robin B. GasserAbstract:Genetic differences among Nematodirus spathiger, Nematodirus filicollis, Nematodirus helvetianus and Nematodirus battus in the nucleotide sequence of the second internal transcribed spacer (ITS-2) of ribosomal DNA ranged from 3.9 to 24.7%. Pairwise comparisons of their ITS-2 sequences indicated that the most genetically similar species were N. spathiger and N. helvetianus. N. battus was the most genetically distinct species, with differences ranging from 22.8 to 24.7% with respect to the other three species. Some of the nucleotide differences among species provided different endonuclease restriction sites that could be used in restriction fragment length polymorphism studies. The ITS-2 sequence data may prove useful in studies of the systematics of molineid nematodes.
T A Yazwinski - One of the best experts on this subject based on the ideXlab platform.
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the efficacy of eprinomectin extended release injection against naturally acquired nematode parasites of cattle with special regard to inhibited fourth stage ostertagia larvae
Veterinary Parasitology, 2013Co-Authors: James S Hunter, T A Yazwinski, S Yoon, J C Williams, Steffen RehbeinAbstract:Abstract The efficacy of eprinomectin in an extended-release injection (ERI) formulation in the treatment of cattle harboring naturally acquired nematode populations (including inhibited nematodes) was evaluated. Five studies were conducted under a similar protocol in the USA, the UK, and in Germany. All study animals were infected by grazing naturally contaminated pastures. The adequacy of pasture infectivity was confirmed by examining tracer calves prior to allocation and treatment of the study animals. The cattle were of various breeds or crosses, weighing 79–491 kg, and aged approximately 6–15 months. In each study, 20 animals were infected by grazing, and then removed from pasture and housed in a manner to preclude further nematode infections for 8–16 days until treatment. Animals were blocked based on descending pre-treatment body weight and randomly allocated to one of two treatments: ERI vehicle (control) at 1 mL/50 kg body weight or eprinomectin 5% (w/v) ERI at 1 mL/50 kg body weight (1.0 mg eprinomectin/kg). Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. For parasite recovery and count, all study animals were humanely euthanized 14/15 days after treatment. Cattle treated with eprinomectin ERI had significantly ( p Dictyocaulus viviparus, Capillaria spp., Cooperia oncophora , Cooperia pectinata , Cooperia punctata , Cooperia surnabada , Haemonchus placei , Nematodirus helvetianus , Oesophagostomum radiatum , Ostertagia lyrata , Ostertagia ostertagi , Trichostrongylus axei , Trichostrongylus colubriformis , Trichuris discolor , Trichuris skrjabini , and Trichuris spp.; developing fourth-stage larvae of Ostertagia spp. and Trichostrongylus spp.; and inhibited fourth-stage larvae of Cooperia spp., Haemonchus spp., Nematodirus spp., Oesophagostomum spp., Ostertagia spp., and Trichostrongylus spp. Animal treatments were well accepted, with no adverse reactions to treatment observed in any study animals. The results of this series of controlled studies demonstrated high therapeutic efficacy and acceptability of eprinomectin ERI against pulmonary nematodes and a wide range of gastrointestinal parasitic infections, including inhibited gastrointestinal nematodes, in cattle.
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Control trial and fecal egg count reduction test determinations of nematocidal efficacies of moxidectin and generic ivermectin in recently weaned, naturally infected calves.
Veterinary parasitology, 2013Co-Authors: T A Yazwinski, C. A. Tucker, E Wray, L Jones, J Reynolds, P Hornsby, J PowellAbstract:An anthelmintic efficacy study was performed with young, naturally infected beef-type calves obtained at local farms. Presumably, the study calves had been recently weaned and had not been treated with a parasiticide prior to study acquisition. After blocking the 24 study calves in accordance with calculated Cooperia spp EPG counts, the calves were randomly allocated within each block to one of four treatment groups, resulting in 6 animals per treatment group (untreated controls, topical ivermectin at the rate of 500 mcg/kg BW [Noromectin Pour-On(®) Norbrook], topical moxidectin at the rate of 500 mcg/kg BW [Cydectin Pour-On(®) Boehringer Ingelheim Vetmedica (BIVM)] and injectable moxidectin at the rate of 200 mcg/kg BW [Cydectin(®) BIVM]. After treatment, the animals were penned by treatment group until necropsy. Fecal, strongyle egg count reduction percentages at 2 days post-treatment were 13, 52, 81 and 93 for control, topical ivermectin, topical moxidectin and injectable moxidectin treatment groups, respectively. In the same order as above, egg count reduction percentages at necropsy (15-18 days post-treatment) were -14, 91, 94 and 97. Based on geometric means for worm burdens quantified at necropsy, anthelmintic efficacies ranged from 96 to 100% for adult Oesophagostomum radiatum, Ostertagia ostertagi, Haemonchus placei and Trichostrongylus axei. Against adult Nematodirus helvetianus, percent efficacies based on geometric means were 56.7, 98.3 and 82.2 for topical ivermectin, topical moxidectin and injectable moxidectin, respectively; an observation that is guarded, as only 5 control animals were infected with adult N. helvetianus. Respective anthelmintic efficacies (%'s) against adult Cooperia oncophora and C. punctata were 93.0 and 73.4 (topical ivermectin), 99.3 and 99.9 (topical moxidectin) and 46.1 and 93.6 (injectable moxidectin). Judging from these data, it appears that treatment of calves soon after weaning with topical moxidectin is effective (>90% efficacy) for all common nematodes in cattle, but injectable moxidectin and topical ivermectin have limited effectiveness against Cooperia spp. With Cooperia spp and H. placei infections, the fecal egg count reduction test and the control trial determinations of anthelmintic effectiveness were in disagreement regarding injectable moxidectin and topical ivermectin.
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Nematode burdens of pastured cattle treated once at turnout with eprinomectin extended-release injection.
Veterinary parasitology, 2012Co-Authors: Steffen Rehbein, T A Yazwinski, Bruce N. Kunkle, E. G. Johnson, Dg Baggott, S Yoon, L.g. Cramer, Soll Mark DAbstract:Abstract The efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against infections with third-stage larvae or eggs of gastrointestinal and pulmonary nematodes in cattle under 120-day natural challenge conditions in a series of five studies conducted in the USA (three studies) and in Europe (two studies). For each study, 30 nematode-free (four studies) or 30 cattle harboring naturally acquired nematode infections (one study) were included. The cattle were of various breeds or crosses, weighed 107.5–273 kg prior to treatment and aged approximately 4–11 months. For each study, animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: ERI vehicle (control) at 1 mL/50 kg bodyweight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of 15 and 15 animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, all animals grazed one naturally contaminated pasture for 120 days. At regular intervals during the studies, fecal samples from all cattle were examined for nematode egg and larval counts. In four studies pairs of tracer cattle were used to monitor pasture infectivity at 28-day intervals before and/or during the grazing period. All calves were weighed before turnout onto pasture and at regular intervals until housing on Day 120. For parasite recovery, all study animals were humanely euthanized 27–30 days after removal from pasture. Cattle treated with Eprinomectin ERI had significantly ( p p 92%: Dictyocaulus viviparus (adults and fourth-stage larvae (L4), Bunostomum phlebotomum , Cooperia curticei , Cooperia oncophora , Cooperia punctata , Cooperia surnabada , Cooperia spp. inhibited L4, Haemonchus contortus , Haemonchus placei , Haemonchus spp. inhibited L4, Nematodirus helvetianus , Nematodirus spp. inhibited L4, Oesophagostomum radiatum , Oesophagostomum spp. inhibited L4, Ostertagia leptospicularis , Ostertagia lyrata , Ostertagia ostertagi , Ostertagia spp. inhibited L4, Trichostrongylus axei , Trichostrongylus colubriformis , Trichostrongylus spp. inhibited L4, Trichuris discolor , and Trichuris ovis . Over the 120-day grazing period, Eprinomectin ERI-treated cattle gained between 4.8 kg and 31 kg more weight than the controls. This weight gain advantage was significant ( p All animals accepted the treatment well. No adverse reaction to treatment was observed in any animal in any study.
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Nematocidal efficacy of eprinomectin, delivered topically, in naturally infected cattle.
American journal of veterinary research, 1997Co-Authors: T A Yazwinski, G.l. Zimmerman, W.k Langholff, J E Holste, E. G. Johnson, D.r. Thompson, M. D. Drag, J.s. EaglesonAbstract:OBJECTIVE To assess the nematocidal efficacy of eprinomectin in naturally infected cattle. ANIMALS 62 (31 eprinomectin-treated and 31 control) beef mixed-breed or Holstein cattle, either 6 to 11 or 48 to 96 months old. PROCEDURE Cattle were housed 21 to 27 days before treatment to allow parasites to reach maturity. Animals were grouped by sex, ranked by weight, and randomly assigned to treatment group. Fecal flotation was done to identify cattle with intestinal nematode infections. Treatment groups were: 1--eprinomectin topical vehicle (1 ml/10 kg) and 2--eprinomectin topical solution (1 ml/10 kg). Cattle were euthanatized by replicate on day 14 or 15, and standard procedures were used to recover of pulmonary, abomasal, small intestinal, and large intestinal nematodes. RESULTS Eprinomectin efficacy across all trials was 100% against adult Trichostrongylus axei, Haemonchus placei, Oesophagostomum radiatum, and Dictyocaulus viviparus, as well a fourth-stage larval Oes radiatum, Ostertagia ostertagi, Nematodirus helvetianus, and Cooperia spp. Efficacy against adult O ostertagi, Cooperia oncophora, C punctata, C surnabada, C spatulata, N helvetianus, Trichuris sp, and Trichuris fourth-stage larvae was 99.9 and 99.8, 99.6, 98.9, 98.3, 99.7, 97.8, and 84.3%, respectively. All results were significant (P < 0.01) except those for C spatulata. Adverse reactions were not observed. CONCLUSION AND CLINICAL RELEVANCE Eprinomectin is a safe and effective nematocide against naturally acquired nematode infections in cattle when administered at a dosage of 500 micrograms/kg. Milk and meat withholding is not necessary when using this product.
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EFFECTIVENESS OF DORAMECTIN FOR TREATMENT OF EXPERIMENTALLY INDUCED GASTROINTESTINAL TRACT LARVAL NEMATODE INFECTIONS IN CALVES
American Journal of Veterinary Research, 1994Co-Authors: T A Yazwinski, Featherston H, C. A. TuckerAbstract:Anthelmintic efficacy of doramectin, a macrocyclic lactone of the avermectin family, was evaluated against larval parasitic nematodes in calves. The investigational product was given SC at a dosage of 0.2 mg/kg of body weight to 10 calves infected 6 days previously with third-stage larvae of the genera Haemonchus, Ostertagia, Cooperia, and Nematodirus. Ten additional calves with identical larval exposure were given saline solution SC also at 6 days after inoculation, and served as the nonmedicated controls. At 14 or 15 days after treatment, the calves were slaughtered in complete replicate for nematode recovery and subsequent quantifications. In comparing nematode numbers at necropsy for the saline- and doramectin-treated groups, nematocidal effectiveness as directed against fourth-stage larvae was: 100% for Haemonchus placei and Cooperia spp, > 99% for Ostertagia ostertagi, and 64.5% for Nematodirus helvetianus. All treatments were easily administered, and adverse behavioral or tissue reactions were not seen to result from doramectin administration.
