Seasonal menace: Protecting livestock against external parasites

While rain followed by sunshine produces the eye-catching sight of a rainbow, it can also mark the need for livestock owners to confront the insects and parasites that thrive in the summer season.

To help owners protect their livestock, Dr. Isabelle Louge, a clinical assistant professor at the Texas A&M School of Veterinary Medicine and Biomedical Sciences, provides insight into the importance of external parasite control and discusses methods for reducing the potential health risks associated with common farm pests.

Perilous Pests

Livestock — including horses, pigs, cows, sheep and goats — are highly susceptible to insects and the parasites they carry this time of year.

“As the weather gets warm and wet, the flies begin to come out in large numbers,” said Louge. “Flies are irritating to livestock, but they also pose health risks to them.”

Horse-, deer-, horn-, sand- and face-flies are a tremendous hindrance on the lives of farm animals, but they are not the only culprit — the disease-transmitting threat of external parasites also extends to various species of mites, mosquitos, ticks, and lice. 

Beyond the skin wounds and lesions they cause, these pests’ attacks can potentially infect animals with diseases that can cause issues ranging from eye infections to abortion storms (a sudden increase of lost pregnancies within a herd); these diseases also can include:

● Pink Eye - a bacterial infection affecting the surface of the eye, potentially causing blindness and eye lesions.

● Bluetongue - a viral disease causing difficulty breathing, depression, fever, and reproductive issues.

● Anaplasmosis - a disease causing anemia, fever, and overall weakness.

“In addition to illness, the insects themselves also can cause the animals to drop body condition by distracting them from eating and deteriorating their hoof quality by making them stomp more,” Louge said.

Reducing Risk

Protecting farm animals from diseases spread by insects starts with insect prevention. 

It is imperative to remove manure waste from the livestock’s pen on a regular basis. Remaining diligent in water hygiene also is an effective way to reduce insect populations. 

“Flies often reproduce in manure, so removing this from the environment will help reduce their ability to reproduce in large numbers,” Louge explained. “Also, many biting insects require standing water sources to reproduce, so eliminating stagnant standing water by dumping out buckets frequently and replenishing water sources can help drive their numbers down.” 

For further insect protection, Louge notes that products such as fly tags, fans, fly masks, and pour-on products may help control the issue depending on what external parasites are present.

“It’s important to note that many of these products are available over the counter, but care should be taken to only use them as directed on the label,” Louge said. “These products are pesticides and can contaminate waterways and impact the populations of beneficial insects when used incorrectly.”

Ultimately, watching out for external parasites affecting your livestock and working with your veterinary care team is crucial in maintaining livestock health. 

“Like always, if you suspect an issue with these external parasites, it’s a good idea to speak with your veterinarian who can help identify the pests and help you decide what control options would work best for your farm,” Louge added.

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