Objective evaluation of two deworming regimens in young Thoroughbreds using parasitological and performance parameters.

This study evaluates the effects of two different deworming treatments for young Thoroughbred horses, examining the impact on the horse’s growth rates, fecal egg counts, and body condition. Findings indicate that while the type of treatment did not have a significant effect, the age of the horse did, and there were concerns about reduced effectiveness with some deworming drugs. However, good management practices mitigated the negative effects of parasitism on the horses.

Research Design and Methodology

• The researchers used 48 Thoroughbred foals from three farms in central Kentucky.
• The foals were randomly divided into two treatment groups. One group was subjected to an interval dose program, while the other group received daily deworming.
• Both pre- and post-treatment effectively assessed the impact of the deworming formula in the issues of strongyle and ascarid parasites and their impact on the horse’s health.

Key Findings

• Fecal egg counts for ascarid and strongyle parasites did not significantly differ between the two treatment groups.
• Differences in the fecal egg counts were significantly influenced by the age of the horse however. Ascarid counts peaked at 4.5 months of age, while strongyle counts continuously increased.
• Reduced efficacy of certain deworming drugs, including ivermectin and moxidectin for strongyles and ivermectin for ascarids, was observed.
• The average daily gain or growth rate was not significantly affected by the deworming treatment, but was significantly influenced by the age of the horse. This mirrored previous data on Kentucky Thoroughbreds born in 2013.
• Body condition scores remained in the optimal range (5-6) for both treatment groups throughout the study.

Implication and Conclusion

• The study showed that certain deworming drugs might not be as effective as believed. However, with good farm management practices, growth rates could be maintained and body condition scores could remain in the optimal range.
• The findings also suggested that the age of the horse had a significant effect, indicating a potential need for age-specific deworming treatments.
• This study provided insight into how performance parameters can be useful for assessing parasite control, especially when drug efficacy is not optimal.