Hay delivered to drought-stricken areas could distribute liver flukes
DULUTH, Ga. — December 5, 2007 — Drought-stricken producers buying hay from out of state may need to take extra precautions when it comes to parasite control.
“It is possible to move liver flukes in hay that is taken from an area known to have flukes,” says Dr. James Hawkins, Merial Veterinary Professional Services Associate Director. “Under ideal conditions, liver fluke cysts can survive on hay for a period of several months.¹ Cattle can ingest those cysts and become infected with liver flukes.”
Liver fluke infections can rob producers of dollars in the form of reduced weaning weights, pregnancy rates and rate of gain, and, in some cases, can even cause death.² With continuing drought conditions in the West and Southeast, Dr. Hawkins says liver flukes will have more opportunities to spread by hay and through infected cattle being sold and distributed throughout the country.
“Mississippi, Alabama, Georgia and Tennessee are in a severe drought,” says Dr. Christine Navarre, Louisiana State University Extension veterinarian. “Producers are downsizing herds and bringing in hay from surrounding areas known for liver flukes. At this point, feeding hay is about the only thing producers can do if they want to keep their cattle.”
If liver flukes are introduced to new areas through hay or purchased cattle, producers may face even greater losses if proper precautions aren’t taken.
“When liver fluke-infected cattle are combined with cattle naive to the parasite, the naive cattle are more likely to develop clinical disease instead of the subclinical disease normally seen in fluke-endemic regions,” Dr. Navarre says. “And that means greater production losses. Also, liver flukes can become established in the area, and then producers will have an ongoing problem.”
Liver flukes or other internal parasite loads can further undermine cattle that are already nutritionally compromised due to drought.
“If cattle are nutritionally deprived and have parasites, health and development problems can compound other health issues,” Dr. Navarre says. “The overall health of the cattle will continue to decline and they likely will not recover as quickly when conditions return to normal. The bottom line is that producers will sacrifice profits if parasites aren’t controlled.”
Dr. Navarre also notes that other economically important parasites, such as Ostertagia ostertagi, the brown stomach worm, are capable of surviving drought conditions. A plot in one study showed that parasite larvae survived for 18 months in dung pats, including a period of prolonged drought.³ It also showed that the larvae levels on pastures were extremely high after rains resumed.³
Dr. Hawkins says producers should continue to treat cattle for parasites during and after drought. Plus, he says, producers purchasing hay or cattle from liver fluke-endemic regions should be sure to include liver fluke control as part of a strategic parasite control program.
“Not all parasite control products kill liver flukes, so producers should be sure to read product labels carefully or contact their local veterinarian to learn more about liver fluke treatment options,” Dr. Hawkins advises.
Merial is a world-leading, innovation-driven animal health company, providing a comprehensive range of products to enhance the health, well-being and performance of a wide range of animals. Merial employs approximately 5,000 people and operates in more than 150 countries worldwide.Its 2006 sales were nearly $2.2 billion. Merial Limited is a joint venture between Merck & Co., Inc. and sanofi-aventis. For more information, please see www.merial.com.