This is the time of year that animals are out grazing on pastures and will begin to pick up parasite loads from those pastures.
Sheep and goat producers who have been in the business for any length of time can readily name all of the parasite control measures that have been recommended over the years: deworm regularly, rotate dewormers and perhaps deworm all animals at the same time, and the list goes on.
The problem with these recommendations and other contributing factors is that they are ultimately to blame for the development of parasite resistance to dewormers. With that in mind here are some recommendations to help producers avoid any further development of resistance on their farms.
Our public enemy #1, Haemonchus contortus, or more commonly the barber poll worm, is responsible for most losses from roundworm parasitism. For this parasite, a management tool referred to as FAMACHA has been developed. FAMACHA is a method of identifying individuals within the herd that have a heavy parasite load based on physical evidence of anemia caused by the barber poll worm.
A colored chart (scale of one to five) is used to assess each animals level of anemia based on the color of the pinkish tissue inside the lower eyelid or conjunctiva. Animals with scores of four and five (palest and most anemic) should be treated or culled from the herd.
Conversely, animals with scores of one or two do not need treatment. For animals scoring a three, they may or may not require treatment.
Producers should use the FAMACHA color chart along with various other factors to determine a need for treatment. FAMACHA can only be used to determine treatment for the barber poll worm.
For other parasites, treatment should be based on the individual animal’s body condition, age (younger animals are of more concern), fecal egg counts which can be done by a veterinarian, pregnancy or lactation status, performance/production and any signs of illness. Animals should be weighed before treatment in order to administer the correct amount of dewormer. Always dose the full and correct amount, and read/follow the label on the product you are using.
With sheep and goats, consult with a veterinarian on the correct dosage based on weight as extra-label dosages are usually recommended. Contrary to the recommendation that producers received for years to deworm every individual in the herd every 3 to 6 months, the current recommendation now is for producers to be selective about deworming and to use a dewormer until it is no longer effective before they rotate.
Small ruminant producers or prospective producers can find out more information pertaining to this article by contacting me at 586-4009 or by email at email@example.com
Kendra Fortner is the N.C. Cooperative Extension Agent, Livestock, for Jackson and Swain counties.