Parasites and the Beef Herd
Published on Mon, 04/03/2023 - 1:44pm
Parasites and the Beef Herd.
By Jaclyn Krymowski.
Compared to other livestock species, beef cattle tend to muscle through their internal and external parasite loads impressively well. Often, clinical signs only come to the surface during especially severe loads or with immunosuppressed animals.
That said, the subclinical infestation each animal carries is still silently costing you dollars and impacting overall health. The issue is (when dealing with healthy animals who bear their parasitic burdens well) that it is hard to know exactly how significant the infection is at any given time.
This means that ongoing measures for both parasite prevention and management are essential.
Both internal (worms) and external (fleas, flies, ticks, etc.) parasites draw nutrients from the host and can cause disease.
Negative effects of parasites can vary from subclinical immune or appetite suppression, irritation, or decreased production and weight gain to severe clinical disease with the potential of death.
A good health program is more than a series of product administrations and chemical treatments. Rather, it should seek to aid in strong immune systems and overall healthy animals by means of nutrition, good general practices and overall pasture management.
The majority of internal parasites are worms. Roundworms, tapeworms, and flukes are some of the common ones, with roundworms being a key for most operations to focus their prevention programs on.
Regardless of parasite types in a given region, understanding the lifecycle is necessary to establish a health and prevention protocol for the herd.
Eggs (which typically hatch in the gastrointestinal tract after oral consumption) are shed through the manure and begin to develop transitioning from a first-stage larva (L1), to second stage larva (L2), and then into a third and infective-stage larva (L3).
The infective stage larva is well protected and survives in the grass where they are consumed. Once the cattle consume them, most species will mature into adults in about three to four weeks.
External parasites feed on body tissues and can cause wounds and skin irritation which leads to discomfort for the animal. They also can transmit diseases and risk healthy animals and affect the whole herd’s weight gain, lactation, or meat production much like internal types.
Times of greatest concern for external parasites include prior to weaning and during intensive grazing. This is especially true when these events coincide with the warm weather months when parasites are most active, shedding and reproducing.
On a biological level, weaning causes significant stress for young animals and immunosuppression is one of the biggest impacts. Producers should work with their vets for the most effective modes of prevention for their young animals during this time.
Fecal flotation tests should be performed annually, if not seasonally, to determine egg counts and species types due to the subclinical nature of many internal parasitic infestations. In some cases, blood testing may also be necessary.
When infestations are clinical, the symptoms can vary greatly depending on the infected animal, meaning an older animal will be more severely impacted. These can range from fever, anemia, jaundice, general weakness, heavy breathing, reduction in feed consumption or even abortions.
For external parasites, there are three types of controls: biological, cultural, and chemical. Biological control includes properly identifying the insect population, while cultural control manipulates the pest’s environment to reduce conditions for the pest. Lastly, chemical control means using pesticides (per their label) to try to limit or rid external parasite infection, according to the University of Alabama extension bulletin Managing External Parasites of Beef Cattle in the Southeast.
Some insecticide application methods include dips, dusts, ear tags, pour-ons, sprays and etc. Alabama A&M University and Auburn University have a useful guide to applying and utilizing such applications.
With the growing rise of regenerative practices and push to use less chemicals, there are some non-traditional parasite and pest management protocols hitting the industry. These include biological fly controls with predator wasps, routinely administered herbal dewormers, toners, and grazing forages that are high tannins.
Given that selection of parasitic control needs to be made mindfully and releative to a particular farm or ranch. These should be evaluated not only at the individual animal level but also as part of whole herd pasture management.
Some powerful pasture management tools that combat parasite populations include rotational grazing, cross-species grazing, and avoiding grazing during heavy wetness or other times when worm loads are especially high.
Herd health programs should include internal and external parasite control as part of overall herd management practices. Animals can be kept healthy and productive by providing adequate nutrition, mitigating stresses, deworming and other precautions against harmful parasites.