[Testing of a deworming scheme for horses].

The research aimed to test the efficacy of a horse deworming scheme, which involved treating horses at turn out, then again 4 and 8 weeks later. The study, conducted in 1983 and 1984, measured result through indicators like egg output, larval differentiation, weight gain, herbage infestation and percentages of some serum proteins.

Participants and Methodology

• The 1983 experiment involved 42 mares, 54 two-year-old male horses and 42 male yearlings, kept in groups with either permanent or rotational grazing. In 1984, the study was restricted to 90 male yearlings.
• Ivermectin and albendazole were used for deworming in 1983, while only ivermectin was used in 1984.
• The effect of the treatments was measured by examining the fecal matter of the horses for egg per gram (EPG) counts, observing the level of herbage infestation, and studying the weight gain of the horses.
• Changes in the percentages of certain serum proteins were also recorded in the 1984 experiment.

Findings

• Fecal examinations revealed that ivermectin was more effective in reducing EPG, with counts remaining low or zero for a longer period compared to albendazole.
• Post-treatment, no larvae of large Strongyles were detected, regardless of whether ivermectin or albendazole was used.
• Herbage infestation reflected prior grazing by the treated horses, with peak infestations in late summer and autumn, while early to mid-summer had the lowest infestation levels.
• No significant differences in weight gain were detected between the groups of horses, and serum protein levels dropped post-treatment but remained stable thereafter, irrespective of reinfection in autumn.

Conclusion and Recommendations

• Despite the deworming scheme, worm infestations were high in late summer and autumn, indicating that the existing system was unsatisfactory in preventing worm infestations.
• The researchers suggested a modified deworming schedule which includes treating horses at least 48 hours before turn out, deworming every four weeks until July, and additional treatments in September and November.