Timely Topics for 2013
Is the fungus still among us?
James Miller, December 2013
Livestock defecate on pasture, and feces include gastrointestinal (GI) nematodes eggs. For completion of the life cycle of GI nematodes, larvae that hatch from eggs have to develop and survive to the infective stage and then migrate out of the feces to be consumed by grazing animals.
Duddingtonia flagrans is a nematode-trapping fungus that is able to eliminate the majority of those free-living larval stages in the feces. This is accomplished by incorporating D. flagrans spores into a daily feed supplement. They are able to survive and pass through the GI tract and are deposited in the feces along with the nematode eggs.
Copper oxide wire particles to control Haemonchus contortus in small ruminants
Joan Burke, November 2013
Haemonchus contortus or barber pole worm is a threat to small ruminants in the southeastern states and as far north as Canada, during warm, moist summers. H. contortus is a blood feeder associated with anemia and death losses of sheep and goats. Due to the presence of anthelmintic (or dewormer) resistance, alternative methods of control are necessary. Copper oxide wire particles (COWP) have been shown to reduce infection of H. contortus, but not other parasitic worms. There are risks involved in using COWP as a dewormer.
Potential solutions for highly resistant worms
in sheep and goats
Steve Hart, October 2013
Highly-resistant (to dewormers) worms occur due to the overuse of dewormers, importing resistant worms in newly acquired animals, and lack of an effective parasite management program.
Finding an effective way to deworm animals (discussed later) will only provide short-term relief for the problem and not solve the problem in the long-term. If you have significant dewormer resistance, you are going to have to develop a parasite management plan if you want to stay in the sheep/goat business for the long-term
Anne Zajac, September 2014
While many internal parasite infections of sheep and goats can only be diagnosed with the use of a microscope, tapeworm infections are all too apparent. Tapeworm segments, either individually or in long chains, can be seen in manure or even emerging from the host animal, and are a familiar sight to most sheep and goat owners.
The most common tapeworm of sheep and goats is Moniezia (pronounced Moe-knee-zee-ya) expansa. Adult tapeworms live in the small intestine. Of course, the important thing about tapeworms for the small ruminant producer is whether they affect animal health.
Should I consider using LongRange dewormer for parasite control in small ruminants?
Ray Kaplan, August 2014
LongRange™, a relatively new product from Merial Ltd. is gaining wide scale use in cattle, for which the product was developed. I often receive questions about whether this product would be good to use to control parasites in small ruminants.
LongRange™ contains the drug eprinomectin, which is also found in the cattle pour-on product Eprinex®. Eprinomectin is in the same family of drugs as ivermectin (Ivomec®). This family of drugs, the macrocyclic lactones (or MLs), also includes the drugs doramectin (Dectomax®) and moxidectin (Cydectin®).
High quality forage helps maintain resilience to parasites
Ken Turner, July 2014
Maintaining forages with high nutritive value (including increased protein levels by utilizing legumes in pastures) helps to increase resilience in sheep and goats to GI parasites. When grazing sheep and goats on pasture, resilience can be defined as the animal’s ability to tolerate higher GI parasite burdens and still remain productive (gain weight; produce milk).
In a 2012 study, meat goat kids grazing alfalfa or red clover (legumes, high protein) pastures gained more weight compared to goat kids grazing orchardgrass pasture despite an increasing fecal egg count in all animals. Meat-goat kids grazing alfalfa or red clover appeared to be more resilient to GI parasites than goat kids grazing orchardgrass.
Pine bark and other natural dewormers for small ruminants
Byeng Ryel Min, June 2014
Alternative methods of GI parasite control for animals raised primarily on forages are vital for the sustainability and profitability of sheep and goat farms in the United States.
Researchers at Tuskegee University found potential benefits of pine bark supplementation on anti-parasitic effects and improved feed efficiency. Pine bark is one of the abundant forest by-products in the southern United States and contains 11 to 13 percent condensed tannins on a dry matter basis.
Sericea lespedeza for natural control of coccidiosis
Susan Schoenian, May 2014
Sericea lespedeza (SL) has been scientifically proven to reduce barber pole worm (Haemonchus contortus) infections in sheep and goats. The condensed tannins contained in the lespedeza are credited with control, though the mechanism is not fully understood. Control has been achieved when animals consume SL as either fresh forage, dry hay, or leaf meal pellets.
During various studies, researchers noticed that SL-fed animals also had cleaner hindquarters and required fewer treatments for coccidiosis. This has led to more recent investigations into the effects of sericea lespedeza on Eimeria spp. (coccidia) infections in lambs and kids.
Haemonchus contortus and camelids
Lisa Williamson, April 2014
As is the case in sheep and goats, gastrointestinal parasites are a leading cause of illness and death in camelids. The blood-feeding nematode Haemonchus contortus is especially devastating in camelid herds living in endemic areas. Based on a survey conducted in the Athens, Georgia Diagnostic Laboratory last year, haemonchosis was the cause of death in 12% of the llama and alpacas submitted for necropsy.
Research conducted by the University of Georgia a few years ago on hundreds of llamas and alpacas living on 26 privately owned farms in the southeastern United States found that Haemonchus contortus was the most prevalent nematode parasite on the farms.
Do herbal dewormers work?
Dahlia O'Brien, March 2014
Internal parasite infections are a major cause for reduced productivity in the sheep and goat industry. Before the use of chemical dewormers became widespread, many livestock farmers used natural plant remedies in their herd/flock to control these infections.
With emerging dewormer resistance and an overall increase in the desire to promote sustainability, the use of non-chemical dewormers is desired and sometimes preferred. To this end, the use of commercially-available herbal dewormers might be a promising and viable alternative to chemical control. But, how effective are they in controlling internal parasites?
How can artificial insemination further parasite resistance in sheep?
Joan Burke, Stephan Wildeus, Roxanne Newton, & Kathy Bielek, February 2014
It is often difficult, especially for small flocks, to justify the purchase price of a superior ram, yet the success of these flocks, and the sheep industry as a whole, requires this advancement. The widespread use of artificial insemination (AI) in the cattle, swine, and poultry industries has resulted in accelerated genetic progress for economically important traits, while minimizing exposure to animal diseases.Historically, AI in the U.S. has been limited in sheep due to the complexity of the ewe’s cervix and because of difficulties in storing and thawing frozen semen.
Blueprint for selecting parasite-resistant sheep
Kathy Bielek, February 2015
The concept of selecting parasite resistant sheep is simple: consistently select the animals with the best resistance. Putting the concept into practice, however, can be more challenging. This paper will share some of the lessons learned over the last 10 years through several North Central Sustainable Agriculture Research and Education (NC SARE) grants and on-farm experience. A list of the SARE grants and the breeders involved is included at the end of this blueprint.