Deworming a Filly
Topic: Feeding and Health ManagementWednesday, July 28, 2010I have a 10 month old filly - should she be wormed every 2 months? She was wormed last in December and her stool sample in Feb was negative for eggs.
Provided By: Melissa McKee DVM
Wednesday, July 28, 2010I would not assume that a negative fecal in February means that your filly has no intestinal worms. In Northern climates, most intestinal worms undergo a dormant period during the winter as it makes no sense to shed eggs into a hostile environment. A single deworming dose one month after the first frost in the fall should be sufficient to cover you until April or May when worm populations become active again. Since parasite resistance to most dewormers is becoming widespread, you are better off to deworm based on repeat fecal exams rather than adhere to a specific-interval regime. I would do another fecal near the end of April and again in the mid summer to test the effectiveness of your dewormer. Resistance patterns vary considerable so I would seek your regular vet’s advice about which one to use this spring.