Fecal sample testing is part of monitoring product effectiveness as it helps producers measure the success of their current products and the timing of their deworming program. It can help prove that a current program is working well and identify areas where product and timing changes are necessary. Lastly, while we know there will always be some parasitic infection, fecal sample testing allows us to watch the infection levels and tweak our deworming program based on the results we review. Under your veterinarian’s recommendation, you or a Sioux Nation Ag Center field marketer can obtain samples that adequately represent your herd or flock.

Unsurprisingly, parasites lower livestock feed efficiency and negatively impact immune function, reproductive efficiency, weight, milk yield, offspring yield, and carcass weight. We also know that the parasitic load leads to liver condemnations, lung issues including pneumonia, and other disease transmission. When infestations are allowed to continue, producers may end up spending more on their herd to address these issues, only to realize less return in the end.

Deworming is widely used to address parasitic infestations, and the industry continues to see advances and improvements in practices that help control these infestations. Repeated use of the same product or active ingredient allows the parasite to develop resistance, which happens when the strongest parasites survive the treatment and reproduce offspring with similar strong characteristics, thus reducing product effectiveness over time. Taking a more long-term approach to parasite control is the key to avoid resistant organisms. Using different products at different times, and for different animals is essential to prevent dewormer resistance. Monitoring product effectiveness is also crucial to the long-term deworming approach.

Cattle
Typically, herds of about 100 require about 20 fecal samples for an adequate
testing size. Larger herds need larger sample quantities. Your veterinarian can advise you regarding the number of samples you need to maximize your fecal testing efforts. Try grouping samples from different age groups and review the results based on maturity. Sampling can also be completed for adults in the fall at an appropriate time following deworming and again in the winter to monitor the calves’ treatment. Before deworming, initial fecal sample testing before turnout is an excellent way to determine the baseline of infestation, which will be used to evaluate product effectiveness through a second round of testing.

A veterinarian is an excellent reference to help you establish an acceptable threshold for parasitic infestation. Generally, a high level of infestation is  regarded as anything testing 25 egg count per gram or higher.

We can use additional management practices to control the parasitic load in our herds. Pasture rotation helps create downtime that prevents ingestion of eggs or larvae, which leaves the parasite to die off if left ungrazed long enough.

Refugia is the proportion of a parasite population that remains susceptible to a dewormer. This technique’s concept centers around the parasites not being exposed to dewormer, leaving them in refuge from treatment and slowing dewormer resistance. Only some of the herd is treated. Certain animals receive treatment, including those most susceptible and the most infected. The parasites can reproduce by leaving some animals untreated. They live with their more robust, more product-resistant counterparts, thus preventing the complete establishment of a resistant parasite population within the herd.

The eggs and larvae that have not made their way into a host and are still in the pasture are environmental refugia, as they are not within the herd at the time of treatment. It is important to work with a veterinarian to prioritize which animals to treat, including those with a higher parasitic load or other health concerns.

Swine
Depending on the region, adult pigs 12 months or older should be dewormed every 4-6 months, while the breeding herd, including pregnant females, should be dewormed 2-3 weeks prior to farrowing to prevent the infection of newborns.

Several different types of worms infect pigs. Some thrive in confinement settings and barns, while others are more common in pastures and dry lot facilities. Therefore, working with your veterinarian to develop a treatment plan tailored to your operation is recommended. In addition to proactive deworming schedules, sanitation is critical in preventing the spread of many parasites. Nutrition is also essential for each pig’s ability to fight ff infestation. Keeping gilts away from contaminated lots and weaned pigs from older breeding stock will also help control the parasitical spread. Additional management practices that help control parasitical infestations include performing thorough cleaning and sanitation measures between each farrowing, monitoring and restricting movement of personnel and supplies between areas and operations, and controlling pest and rodent populations that can transport eggs and larvae.

Poultry
Monitoring the flock for worms through fecal sample testing is generally part of routine health protocols and the biosecurity program, with the most critical times being transferring from rearing to production, within the first weeks after beginning production, and again at about 40 weeks old.

However, frequency is established by the lifecycles of parasites in the region. In addition, postmortem examinations by a veterinarian or poultry expert should be conducted on healthy birds with normal feed intake, as the parasitic load of infected birds who have not eaten for days will be high and make an accurate diagnosis difficult.

The treatment approach is both curative and preventative. Infections must be addressed as soon as possible and followed up with preventative activities to avoid re-infestation. Review manufacturer product information and veterinarian advice when treating breeding birds.

Much like in swine settings, there are additional management practices that help control parasitical infestations, including:
• Litter should be kept dry and changed if possible.
• Take advantage of down-times to perform floor-flame disinfection, utilize new disinfectants that destroy nematode eggs, salt wet floors which cause the eggs to float and flush floors after 12 hours, and perform ammonia disinfection under extreme cautions and following local regulations on chemical usage.
• Control pest and rodent populations that can also transport eggs and larvae.

Sheep and Goats
Good management practices and engaging in deworming efforts only when necessary is often the best approach to keeping a lid of parasite infestations in small ruminants. Resistance to deworming products is a considerable issue, making appropriate product use advised by a veterinarian the best approach. When resistance is suspected, testing is a must to determine which dewormer classes and products are  not as likely to be effective. Common deworming strategies include salvage deworming, tactical deworming, and strategic deworming. Which approach works best for you depends on your unique situation and animals; it is worthwhile to discuss these with your veterinarian.

Salvage deworming
In many small ruminant herds, about 20% of the animals are the host for about 80% of the parasites. Salvage deworming is performed by identifying and treating the animals with the highest parasitic loads, which reduces the amount of product used and chances of resistance. This approach requires a great deal of labor as each animal needs to be evaluated for the degree of anemia every two weeks, and high-scoring sheep or goats are often culled or sent to slaughter.

Tactical deworming
When practicing tactical deworming, animals are treated when parasite egg production is highest. Fecal sample testing revealing egg counts over 1,000 per gram in colder temperatures and 2,000 per gram in warmer months are the threshold for tactical deworming.

Strategic deworming
This method concentrates on parasites already within the animal by deworming expectant ewes and does three weeks before the birth of the first baby and again every three to four weeks until the lamb or kid is three weeks old. While this strategy reacts to increased worm egg production in females close to delivery, it does not treat parasites in the environment, where dewormer resistance may easily develop.

With all these deworming strategies, smart guidelines and veterinarian direction should be followed to improve dewormer effcacy and prevent occurrences of resistance.