Intervet Safeguard Dewormer Paste for Horses, 92gm Equine wormer Administer one syringe for each 550 lbs body weight per day. Treatment should be initiated in the spring and repeated in the fall after a six month interval. Equine wormer Administer one syringe for each 550 lbs body weight per day Treatment should be initiated in the spring and repeated in the fall after a six month interval