Effect of antiparasitic medication in ponies on pasture.

This research study investigates the effects of antiparasitic medication on Shetland ponies, and whether this treatment leads to differences in their physical, hematologic, parasitologic, and blood chemical condition compared to untreated ponies.

Study Setup

• Twenty 6 to 7-month-old Shetland ponies naturally infected with gastrointestinal nematodes and stomach bots were divided into two groups of ten. Each group was kept separately on similar pastures free of infective larvae at the study’s start.
• One group of ponies received monthly therapeutic doses of a thiabendazole and piperazine mixture for 17 months, while the second group was left untreated. During the 3rd and 5th months, the treated group also received therapeutic doses of dichlorvos to eliminate bots.

Data Collection

• Weekly observations recorded various physical, hematologic, parasitologic, and blood chemical data. Every group’s weight was measured biweekly.
• At the study’s conclusion, data including worm egg count in fecal samples, body weight, heart girth, packed cell volume, and serum protein content, particularly beta-globulin content, were compared.

Results

• The major differences found between treated and non-treated ponies were in the mean number of worm eggs in fecal samples (0 in treated group vs 1,866 eggs/g in untreated group), mean body weight (151.9 kg for treated ponies vs 117.0 kg for untreated ponies), heart girth (126.5 cm for treated ponies vs 116.3 cm for untreated ponies), packed cell volume (36.4% for treated ponies vs 30.8% for untreated ponies), and serum protein content (8.47 mg/100 ml for treated ponies vs 9.33 mg/100 ml for untreated ponies), particularly in beta-globulin content (mean of 1.9 mg/100 ml in treated ponies vs 3.4 mg/100 ml in untreated ponies).
• The medicated ponies remained clinically healthy throughout the study. They were livelier and proved more difficult to restrain for procedures like blood sampling and weighing than their untreated counterparts.
• No parasitic nematode larvae were found in grass samples from the pasture where the treated ponies grazed. In contrast, such larvae were found in large numbers (up to 500 per 300g sample) in grass samples from the pasture where the untreated ponies grazed.