The efficiency of a mixture of haloxon and trichlorfon against strongyles and bots in horses

Authors: Cook TF
Publication: New Zealand Veterinary Journal, Volume 21, Issue 8, pp 157-159, Aug 1973
Publisher: Taylor and Francis

Animal type: Horse, Livestock
Subject Terms: Alimentary system/gastroenterology, Animal remedies/veterinary medicines, Anthelmintics, Parasite control, Parasites - internal, Nematode, Nervous system/neurology, Toxicology, Poisoning - chemical, Treatment/therapy
Article class: Scientific Article

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Abstract: The effeciency of haloxon (3-chloro-7-hydroxy-4-methylcoumarin bis (2-chloroethyl) phosphate) against ascarids and strongyles in horses has been well documented by Bosman (1966), Neave (1970) and Cook (1973). The drug is slightly effective against bots (Gasterophilus larvae) and it has been suggested that better results would be achieved by the addition of a boticide which might be effective at less that full dosage in combination with haloxon. The drug selected was trichlorfon which is known to be effective against 2nd and 3rd stage Gasterophilus larvae. Trace et al (1962) claimed success at 80 mg/kg; and cited Bolle (1957), who used it at 40 mg/ kg. Delak et al (1966) found that 47 mg/kg removed a large proportion of 3rd stage larvae, but over 100 mg/kg was necessary for complete elimination and that oral and parenteral routes were equally effective. They recommended 60 mg/kg as a reasonably safe and effective level. In further experiments the same workers (1968) reported that 30 mg/kg intramuscularly removed almost 100% 2nd stage larvae. At this level it was less efficient against the 3rd stage which were also more susceptible to oral treatment than by the parenteral route. It was decided to test a mixture of haloxon at 60 mg/kg, which is the full commercial rate and trichlorfon at 20 mg/kg, which represents half the recommended rate in New Zealand. If this mixture were successful, the dose of trichlorfon would be halved again to 10 mg/kg.

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