by Ellen Wren
As anyone raising small ruminants knows, gastrointestinal parasites are a serious threat to the health of their animals. Haemonchus Contortus, more commonly known as Barber Pole worm or Wireworm can cause a healthy lamb to be near death within a week. It is a dangerous blood-sucking roundworm. Hosts experience anemia and protein loss that can progress alarmingly fast, leading to death. Young and highly stressed animals are most vulnerable.
The Barber Pole worm, so named because its red and white stripes resemble old time barber poles, can be difficult to control. It is a prolific egg-layer and is distressingly adaptable. It has a short, direct life cycle, ranging from a little as one week, to three weeks and needs no intermediate host.
They are on the increase due to weather pattern changes. Areas that had not seen severe infestations in the past are beginning to now. Weather conditions directly influence the number of worms found on the grass. They thrive in warm, moist climates. However, some larvae have been shown to survive through winter. This parasite can lie dormant within an animal, awaiting proper environmental conditions. It can survive on pasture for months; a 60-day pasture rest is necessary even to reduce the count. Clearly, these are tough worms to combat.
In the past, commercial dewormer could handle the problem. Today, this hearty parasite has become resistant to most anthelmintics. When sheep and goats are routinely treated, the weaker worms die off. However, the resistant worms live and go on to breed more resistant worms, developing a sort of “super-bug”, not unlike bacteria that infect humans that have become resistant to antibiotics through the overuse of the drugs.
The decision to deworm an entire flock regularly is not only time consuming and expensive, it is also extremely detrimental in the long run. It is no longer a sustainable practice to do so. Since Barber Pole worms have developed a resistance to the drugs used to kill them, very selective deworming must take place, along with strategic culling of the members of the flock with the least natural resistance and worst infestation. It has been shown that around 20 percent of a given flock is responsible for 80 percent of the egg output.
The Famacha Method is an important and relatively simple tool designed to help quickly determine which animals must be treated, which can safety be left untreated, and which are too ill and must be culled to protect the rest of the flock. Developed by three South African researchers and presented there in 2001, the method was first implemented in the U.S. in 2004. Americans have been very receptive to Famacha, and its use continues to surge. It is very important to note that this method is specific to Barber Pole worms and is not of use for any other type of parasite.
The very simple concept behind Famacha is that it’s possible to determine if an animal is sick from Barber Pole worms by quickly examining the mucous membrane of the eye, noting its color. The exam is done by holding the head firmly still, closing the eye and firmly pushing the eyeball inward. The lower lid will pop out, exposing the membrane. Proper lighting is critical. This must be done in full sunlight for an accurate reading. Those wanting to see a visual demonstration of how this is done can find several informative videos online.
The Famacha chart is a small card that is clipped onto the sleeve or worn around the wrist. It has representations of five eyes, each showing a different state from normal to very anemic. Very red mucous membrane is excellent. This shows that the animal is not anemic and has not been affected by the worms. It does not need to be treated at this point.
Very pale or white membranes mean the animal is severely anemic and will need, in the best-case scenario, dewormer and medical care. At this stage, there also remains the possibility of culling the animal to avoid infecting the healthy ones. The three pink stages in between red and white show different degrees of infestation and recommendations for treating or not are given. The foremost goal is to treat less and more effectively to avoid further resistance of the worms to the anthelmintics.
Because of the short life span of the parasite, a good score does not mean an animal is uninfected. It’s always possible that there are already eggs ready to hatch. The eye exam must be done as often as every one to two weeks to catch problems early.
Famacha can reveal which animals are sick, but can give no information about worm load. The next step is fecal sampling; literally counting the number of worms in a defined space, via microscope. To do this, only a 100X magnification microscope and a specific type of slide are needed. Some buy their own kit and microscope and do the straightforward procedure themselves. Fecal testing through a veterinarian can get very costly.
Fecal sampling works along side Famacha to give you more information. From sampling it can be determined which types of worms the animals have and how severe the problem is. Doing sampling before and after dosing an animal can provide data about how well the dewormer is working.
Famacha cards are purchased online. They are inexpensive and it is suggested they be replaced every two years due to fading. Veterinarians may purchase them at any time. Others must take an approved training to be able to purchase the card.
To find a Famacha class in your area, check with your Extension office.