somewhat increasing problem with parasite  control in various livestock, including llamas and alpacas, is the development of drug resistance in worms.  With llamas and alpacas, this is probably even more prevalent by those farms that must administer a monthly Ivermectin treatment as a preventative for Meningeal Worm. 

The primary prevention of parasite control always starts with good herd management.  A good nutritional program and an awareness of the overall health of your animals should be at the top of your list.  Parasites are more likely to seek out and attack weak or compromised animals.  A general lethargy, weight loss, a depressed stance with a humped back, and ball or ploppy stools, rather than pellets, are all signs of possible internal parasites.  Good sanitation, pasture rotation, and the weather also play a big role in the control of parasites on your farm.  Increased attention to possible parasite problems is always needed in periods of extended wet weather.  Barns and pastures should be cleaned regularly and hay and grain should always be fed off the ground and away from manure piles.  Out in dry, sunny areas of the pasture, larvae in manure tends to dry up. But wet shaded areas require additional attention as larvae in manure in these areas may survive for months.  Even winter weather does not defeat some species.  Some infective larvae can even become dormant over the winter, surviving temperatures to twenty degrees below zero, and then become infective again about one month after pastures begin new growth in the spring. 

De-worming programs vary for different areas of the country since various species of worms may be prevalent only in certain areas.  Again, the weather in your part of the country also plays a big part in what you may need to treat for on your farm.   

Previously it has always been recommended to treat all the animals on your farm when de-worming.  However, parasitologists now believe that this common practice is one of the most important factors responsible for the development of de-wormer resistance.  The animals in our herds do not all have an even worm distribution.  Only 20-30% carry 70-80% of the worms and these animals are the ones mainly responsible for contaminating the pastures with parasite larvae for all the other animals.  If breeders could identify those animals and only treat the ones that actually need de-worming, they would save money and greatly reduce the drug resistance.  This could be done with regular fecal checks on each animal in our herd.  Regular fecal checks would allow us to identify the actual worm and administer only the correct treatment and dosage to only those animals that need it. 

For the blood-sucking barber pole worm (Haemonchus contortus), which has been a severe problem in various areas of our llama and alpaca population, a new system called FAMACHA has been developed in South Africa and has been validated in the U.S.  Since anemia is the primary effect from infection with the barber pole worm, often resulting in death, a simple and reliable test for anemia has been needed.  The FAMACHA method provides this test to identify anemic animals.  Breeders regularly check the mucous membranes around animal’s eyes and compare the membrane color to color illustrations on a chart.  The chart portrays various levels of anemia.  Only the animals scored as anemic are then treated which results in fewer treatments, money saved, and slowing the development of a resistance to de-wormers.  It’s reported not to be a difficult system to learn, but one that should be taught by a certified person.

 With increased reports of drug resistant worms in all parts of the country, perhaps it would be advantageous to re-evaluate our own de-worming program with our veterinarian.  We can certainly appreciate the information that has come from the various farms around the country that have shared their experiences and increased our awareness of this important concern in ruminants.

This article, written by Marilyn Nenni, appeared in the Hoosier Hummer newsletter in 2006.