Signs, Symptoms & Treatment of Worms in Cattle

The cost of worm infestation in cattle

Top of mind for any herd manager will be the financial impact of a worm infestation. With appetite loss one of the key indicators of parasites, infected animals will soon show low weight gains. The knock-on effect of this is an undernourished animal less able to cope with the invasion and likely to succumb further. Weight loss from worms can sit anywhere between 15 and 55 kilograms for cattle. With such significant loss in an animal’s value, it’s easy to see how much impact cattle worms can have on profitability.

Treating worms in cattle does not have a one-size-fits-all solution. But the good news is there are some basic factors to consider that will help you reduce the risk of exposure, reduce the risk of reinfestation and decide how to manage worm drenching cattle.

Age: First season calves are more likely to suffer significant impacts from worm burden. Calves have little acquired resistance to worms and an infestation at a young age can impact the animal’s potential production.  As animals become older, they develop more resistance to worm infestation, but it’s important to know that this can wane over the winter period and second-season grazers may become reinfected. As a herd becomes older, they are more likely to hold off serious worm infestation, and less treatment is needed at this age.

Environment: While mature cattle are often more resilient to worms it is worth being aware that an animal who has endured drought conditions is more at risk to worms and the weight loss that can accompany it. In terms of parasite eggs and larvae, hot and wet conditions are most favourable to worm growth, making spring a peak time to be vigilant.

Herd Health: Like any animal, the healthier the animal, the more likely it can resist illness and parasites. Cattle who receive adequate nutrition and have the ability to graze outdoors show greater resistance to the serious effects of parasites. Animals deficient in nutrients show less ability to resist the effects of parasites and are likely to contribute to herd infestation.

What are the signs of worms in cattle?

More time on grass means more likelihood of parasite exposure. This is the reality of herds raised on pasture. So, if keeping your herd year-round on dry lots is not an option, then you’ll need to know how to identify the signs of worms in cattle to avoid the issue getting out of control.

The most reliable way to check for parasite infection in cattle is with a fecal egg count test. But before you get to this stage, you can observe an animal by looking for the visible symptoms of worms, which can include:

• Listless appearance and loss of appetite.
• Watery and profuse diarrhoea
• Sudden weight loss and emaciation
• Poor coat condition

Most common cattle worms by species and region

Parasites lurking within New Zealand pastures are stealthy operators. With external symptoms taking time to show, worms can quickly get a head start on attacking the host. Once it becomes obvious parasites are present - through symptoms such as a poor coat or weight loss - a worm infestation may have well and truly taken hold.

The most common types of worms in cattle found on pasture-raised herds are roundworms, tapeworms and flukes - a category known as internal helminths. Helminths are transmitted through oral ingestion or via direct penetration of the skin by larval parasites.

What causes worms in cattle and how is it treated?

The effects of a severe parasite infestation can be quick to escalate, making swift action essential. Understanding how cattle ingest worms and become infected will help you minimise the severity of an infection. While a treatment program from your vet incorporating drenching will be a strong line of defence, a lot can be done to limit these tiny invertebrates having a big impact.

Worm infestation in cattle begins when grazing animals ingest larvae from pasture at the start of the season. Calves are highly susceptible to worms making them the common culprit in taking a low-level presence of worms into a full-blown infestation. Infected calves cultivate huge larvae populations within their gut and then shed worm eggs onto the pasture for other animals to ingest. The lifecycle of a parasite from egg stage to egg-producing larvae stage is around five weeks.

How to test for worms in your cattle?

Accurate testing is a crucial step [SJ1] in deciding how to treat worms in cattle. Fecal egg counting is a common way to diagnose worm infestation and is most successful when used in cattle under six months of age. A fecal egg count (FEC) determines if anthelmintic (dewormer) treatment is needed. For fecal egg counting to be successful, at least 20 faecal samples from the same herd are needed. Find out more about how Te Pari maintains the world’s largest FEC database and monitors efficacy of anthelmintics here.

Top tips for worming cattle

• Incorporate worming regimes with seasonal changes to ensure treatment is hitting the larvae at the right stage. Larvae can often survive on pasture throughout the winter causing a problem for the following season’s grazing animals. Vigilance pays off.
• Combine treatment with changes in location. Move animals out of pasture known to be infected with larvae. A move to clean pastures is the best way to ensure the cycle does not begin again.
• Rotate worming treatments to avoid the likelihood of parasites becoming immune to a particular product.
• Cattle carrying worms are often suffering from weight loss and emaciation, so it is important to incorporate adequate nutrition alongside any treatment program
• The best strategy for maintaining herd health is to be able to quickly recognise the signs of worms in cattle and know when to start treatment.

How to worm cattle

In most cases, pasture-raised cattle should be treated for worms in the spring to prevent parasite population blooming during summer. Cattle should be mostly parasite-free during the winter months.

It is important to consider the health of the entire herd when treating worms, so cattle should receive two treatments 30 days apart to ensure they will not shed parasite eggs back onto the pasture.

When the time is right, your next step is drenching. Advice from veterinarians for treating worms in cattle is to test before and after treatment and that correct dosage of a dewormer applied correctly is critical. Industry best-practice is to dose each animal according to its weight. Given the need to drench an entire herd simultaneously, weighing each animal and adjusting dosage rates is not a particularly efficient option. 

Here’s where the use of a dosing gun becomes a lifesaver. And Te Pari’s Revolution Dosing Gun Smart Model takes things to a whole new level with super-quick and super-accurate dosing. The smart model uses wireless technology to calibrate the dosing gun automatically from the scales. An accurate dose is delivered to each animal via the battery-powered trigger mechanism.

The dosing gun from Te Pari gives you the innovation needed to get dosing right and get rid of parasites. 

A multi-faceted approach to worm treatment in cattle is the best approach. Applying worm drench to cattle via a dosing gun is the smart way to ensure dewormer is applied correctly, but there are many strategies you can employ before it gets to this stage. Relying on drenching as your sole strategy can result in the re-emergence of infestation and even drench resistance. A preventative, integrated approach is best.