According to Dr. Darren Loula, DVM Christian County Veterinary Service, LLC in Missouri; “Deworming cattle eliminates internal parasites that primarily reduce performance in beef and dairy cattle. Parasites reduce an animal’s appetite, decrease milk production, lower weaning weights, suppress the animals immune system making them more susceptible to disease and decreasing the response to vaccination, and may hinder efficient reproduction. Severe cases may result in significant disease and even death.”
Whitney Whitworth, associate professor of animal science at the University of Arkansas at Monticello said, “Honestly, not all cattle need to be dewormed. Mature animals who are extensively managed, like those in the western U.S., may not receive enough benefit to make anthelmintic use economically feasible. However, all calves will receive benefit from de-worming at weaning.”
Whitworth said that the most critical parasite in cattle is the Ostertagia species, commonly referred to as the brown stomach worm.
Most producers who intensively graze livestock will deworm two times per year, during the spring and fall, usually after the first frost when the worms have gone dormant. “The fall administration is specifically targeted at larvae overwintering in the GI tract,” Whitworth said. “In this case, some producers will also include medication for liver flukes.”
She added that in areas with extremely heavy infestations, administration may need to occur more often.
“De-wormers should target the parasites of interest; the local veterinarian can give specific recommendations for individual farms,” Loula said. “Generally speaking, name-brand dewormers out-perform generics, and injectable dewormers are highly effective against internal parasites. Oral dewormers and pour-ons can be effective when administered properly.”
It is very important to follow label instructions extremely carefully. “Some classes of anthelmintics have much narrower margins of safety for the animals and can be toxic at levels above those recommended,” Whitworth said.
Determining the best way to provide deworming treatment and prevention depends on your situation, the type of animals you raise, and the parasite infestation in your area, Whitworth added. Heavy infestations may require feed-type versions of dewormers, a more constant administration.
According to Whitworth, signs that the dewormer did not take effect (parasite resistance), include reduced appetite, rough hair coat (when others have slicked off), lethargy, anemia and an overall look that tells you the calf doesn’t feel good.
Producers should consult with their veterinarian before beginning a deworming program.
