Transmission of endoparasites in horse foals born on the same pasture on afarm in central Kentucky (1996-1999)

Research carried out during the last 4 years (1996-1999) of an 11-year stud y of the prevalence of internal parasites naturally transmitted to horse fo als born on the same pasture on a farm in central Kentucky is presented her e. Horses in this herd were not treated with any antiparasitic compound for over 20 years except for a replacement stallion in 1994. A total of 22 spe cies, including 12 species of small strongyles, were recovered in the 4-yea r period. Transmission patterns of all species (n = 35) of endoparasites re covered are compared for the 11-year study. Some of the changes were an inc rease in number of Thelazia lacrymalis and Anoplocephala perfoliata and a d ecrease in Gasterophilus intestinalis, Parascaris equorum, and Strongylus v ulgaris. Clinical problems associated with parasitism were not observed in any of the 92 foals in the long-term investigation. (C) 2001 Elsevier Scien ce B.V. All rights reserved.