Seasonal translation of equine strongyle infective larvae to herbage in tropical Australia.
Longevity in faeces, migration to and survival on herbage of mixed strongyle infective larvae (approximately 70% cyathostomes: 30% large strongyles) from experimentally deposited horse faeces was studied in the dry tropical region of North Queensland for up to 2 years. Larvae were recovered from faeces deposited during hot dry weather for a maximum of 12 weeks, up to 32 weeks in cool conditions, but less than 8 weeks in hot wet summer. Translation to herbage was mainly limited to the hot wet season (December-March), except when unseasonal winter rainfall of 40-50 mm per month in July and August allowed some additional migration. Survival on pasture was estimated at 2-4 weeks in the summer wet season and 8-12 weeks in the autumn-winter dry season (April-August). Hot dry spring weather (pre-wet season) was the most unfavourable for larval development, migration and survival. Peak counts of up to 60,000 larvae kg-1 dry herbage were recorded. The seasonal nature of pasture contamination allowed the development of rational anthelmintic control programs based on larval ecology.
Hutchinson
G W
GW
Graduate School of Tropical Veterinary Science, James Cook University of North Queensland, Townsville, Australia.
Abba
S A
SA
Mfitilodze
M W
MW
D000818:Animals; D005243:Feces / Q000469:parasitology*; D006736:Horses; D011793:Queensland; D012621:Seasons; D013319:Strongyle Infections, Equine / Q000469:parasitology*; D013320:Strongyloidea / Q000254:growth & development / Q000502:physiology*; D013323:Strongylus / Q000254:growth & development / Q000502:physiology*; D014329:Tropical Climate