Parasite Control

Deworming recommendations made by the Groton City Animal Hospital.

    Internal parasites are silent killers.  They can cause extensive internal damage, and you may not even realize your animals are heavily infected.  At the very least, parasites can lower resistance, rob the horse of valuable nutrients, and cause gastrointestinal irritation and unthriftiness.  At their worse, they can lead to colic, intestinal ruptures, and death.

    In terms of management priorities, establishing an effective parasite control program is probably second only to supplying the horse with clean, plentiful water and high quality feed.  It's that important!!

IDENTIFYING THE ENEMY

    There are more than 150 internal parasites that afflict horse, including several major species.  Among the most common and troublesome are:

• Large strongyles (bloodworms)

• Small strongyles

• Ascarids (roundworms)

• Pinworms

• Bots

• Tapeworms

• Threadworms

• Lungworms

    Any or all of these parasites can be present in the horse at one time, but they may be at different stages in their life cycles.  This will influence the deworming program needed to combat them.  Also keep in mind that some species can lay more than 200,000 eggs a day, so parasite loads can escalate quickly.

PARASITE DAMAGE

    Different parasites harm the horse in different ways.  They can damage tissues and vital organs, including the major blood vessels to the intestines, lungs, liver, stomach, and intestines, as they migrate through the horse's system to complete their life cycles.  They can cause obstructions and ulcerations within the horse's digestive tract, and they can also cause intense irritation as they lay eggs, such as pinworms do.

SIGNS OF PARASITISM

    Contrary to popular belief, many horses that have dangerous parasite levels appear to be perfectly healthy.  From the outside they may be fat, sleek and shiny, while on the inside the worms are doing irreparable damage.  But in other horses, especially young horses, parasites can take a visible toll.  Signs of infestation might include:

• Dull, rough haircoat

• Lethargy or decreased stamina

• Weight loss

• Coughing and/or nasal discharge

• Tail rubbing and hair loss

• Resistance to the bit due to mouth lesions

• Colic

• Summer sores

• Depression

• Loss of appetite

• Unthriftiness or loss of condition

• Diarrhea

FECAL EXAMINATIONS

    One of the most under-utilized tools in an effective parasite control program is the fecal examination, which merely involves taking two to three fresh fecal balls to your veterinarian for laboratory analysis.  This simple process can identify the specific parasites infecting a horse.  Rarely are worms themselves visible in the manure.  But counting the types and numbers of parasite eggs present in the fecal sample, your veterinarian can recommend the right deworming agents to do the job.  Fecal eggs per gram counts (EPG) also tell an owner about the degree of parasite infestation on a farm or within a herd.

    The fecal exam is a cost-effective follow-up to deworming in determining whether the dewormer has worked.  It's good practice to do a fecal EPG count within two weeks after deworming.

THE IMPORTANCE OF ROTATING DEWORMING AGENTS

    Parasites can develop resistance to many  of the chemicals used to kill them.  After a period, the deworming agents may therefore simply become ineffective.  To prevent this, it's important to rotate classes of drugs used in your program.  Be sure that your don't simply change brand names, however, since many products contain the same drugs but under different labels.  Although some manufacturers claim that certain products do not require rotation, a good safeguard is to do it anyway.  That way, there's no question about resistance developing.  With opinions varying as how often dewormers should be rotated, it is recommended to consult your veterinarian for guidance. 

    By utilizing broad-spectrum deworming agents and rotating them as recommended by your veterinarian, you should be able to rid your horse of most worms.

DEWORMING SCHEDULES

    The best way to set up a deworming schedule is to consult your veterinarian.  Horses at different ages and stages have varying needs concerning parasite control.  For example, young foals are especially susceptible to ascarid (roundworm) infestation, and may require deworming at thirty-day intervals until they build some natural resistance.  Older horses turned out on a large acreage might do well on a semiannual schedule.  And some owners may prefer to have their horses on a continuous control program whereby the horse is given a daily dose of dewormer through a feed additive.

    Climatic conditions and season of year can also influence parasite levels.  Your veterinarian may recommend that you concentrate deworming efforts when your horse's exposure to parasites is at its peak.  Other veterinarians may prefer that you deworm at regular intervals, such as every sixty to ninety days.  Still others may recommend that you prevent parasitism with a daily dewormer.  In any case, the goal is to keep parasite loads to a minimum.

A COMPLETE MANAGEMENT PROGRAM

    Importantly, chemical control is just one part of a total parasite control plan.  Since parasites are primarily transferred through manure, good management is also key.  You should:

• Pick up and dispose of manure droppings on a regular basis (at least twice weekly)

• Mow and harrow pastures regularly to break up manure piles and expose parasite eggs and larvae to the elements

• Rotate pastures by allowing other livestock, such as sheep or cattle, to graze them, thereby interrupting the life cycles of equine parasites

• Group horses by age to reduce exposure to certain parasites and maximize the deworming program geared to that group

• Keep the number of horses per acre to a minimum to prevent overgrazing and reduce the fecal contamination per acre

• Use a feeder for hay and grain rather than feeding on the ground

• Remove bot eggs quickly and regularly from the horse's haircoat to prevent ingestion

• Rotate deworming agents, not just brand names, to prevent chemical resistance

• Consult your veterinarian to set up an effective and regular deworming schedule

SUMMARY

    With the many safe, convenient products available today, establishing an effective deworming program is easy.  Discuss a plan with your veterinarian and implement it without delay.  A good parasite control program will go a long way toward maximizing your horse's appearance, performance and comfort.  The net result will be an animal that's as healthy on the inside as it appears on the outside.

This information was provided by the American Association of Equine Practitioners.

In general GROTON CITY ANIMAL HOSPITAL recommends the following deworming schedule:

    ADULT HORSES:    Deworm every 6 to 8 weeks, rotating the type of active ingredient for maximum effectiveness and minimal resistance.

JANUARY:    Five days of a double dose (double the body weight) of Panacur or single dose of Quest dewormer (Moxidectin) for encysted small strongyles.

MARCH:    Deworm for tapeworms.  Use Ivermectin plus Praziquantel, a double dose of Strongid (double the body weight), or 30 days of a daily dewormer (Strongid C2X or Continuex).

MAY:    Any of the three types (i.e. Ivermectin, Safeguard or Strongid).

JULY:    Benzimidazole type (i.e. Panacur, Safeguard).

SEPTEMBER:    Pyrnatal Pamoate type (Strongid, Rotectin 2).

NOVEMBER:    Ivermectin type (as listed above) for bots.

    Horses in high exposure situations, for example in a boarding stable with high numbers of horses on small acreage, may need to be dewormed monthly.  A better option is to place these animals on "a continuous type" of daily dewormer (i.e. Strongid C2X) with twice yearly of an ivermectin product (Quest gel and ivermectin based products) to control bot and small strongyles.

    Older horses with access to very large acreage may do well with a semiannual deworming schedule, as their risk of infection is less.

    YOUNG HORSES:

    Young horses are more susceptible to infection with parasites as they have not developed any resistance to them.  They are also most likely to show signs usually associated with parasitism (potbelly, rough haircoat, diarrhea, thin body condition, and poor growth rate).

    Because young horse are more susceptible to roundworms (ascarids), they need to be dewormed more frequently early  on in their lives.

    Current recommendations include:

    Deworm monthly for the first 6 months of life, followed by going on the adult schedule.  Use of Pyrantal Pamoate (Strongid) and Fenbendazole types (Panacur, Safeguard) are recommended for the first three months.  Another option is to deworm monthly for the first three to four months of life followed by the use of a daily continuous type of dewormer when the foal is consuming grain on it's own.

*** Prevention of future parasite related internal problems begin with a proper deworming program in young horses!!

    Dewormers are available in oral paste or gel and liquid forms as well as granular and pellet forms that can be mixed with the feed.  Spend some time putting together a deworming program for your horses to help prevent future costly and potentially deadly problems.

    Give us a call today for help in setting up a deworming program.

Groton City Animal Hospital

794 Cortland Rd. (Rte. 222)

Groton, NY 13073

(607)898-4482