The use of commercial livestock dewormers has paid off in terms of animal health and productivity, but it has also resulted in resistance among parasite populations.

“As dewormers lose effectiveness, producers need to develop a broader strategy for managing internal parasites in their livestock,” said Eric Meusch, University of Missouri Extension livestock specialist.

Resistance to deworming products

A recent study funded by Merck Animal Health and led by Eric Bailey of the University of Missouri conducted fecal egg count reduction tests in beef herds across the state, finding resistance to macrocyclic lactone dewormers (avermectin-type dewormers). The benzimidazole class of dewormer (“white” dewormer) still showed efficacy above the threshold for effective deworming, which is 90%. The results of the Missouri study are consistent with a larger data set compiled by Merck Animal Health.

The dewormers losing efficacy are products commonly used in pour-on and injectable forms and have become popular due to cost and ease of administration.

“The popularity and frequency of use of these products has likely led to resistance,” said Meusch.

Understanding the enemy

To manage parasites, it is important to understand their life cycle, said Meusch. Stomach worms must complete several life-cycle stages both inside the gastrointestinal tract of cattle and on the pasture. The cows can only be infected by consuming grass from infected pastures, and pastures can only be infected by cows carrying adult stomach worms.

Worms that are resistant to a dewormer (less than 90% are killed by the treatment) survive and lay eggs that are deposited in the pasture. Over time, the percentage of resistant larvae increases in the pasture until the animals are infected with worms that can no longer be controlled with the product.

Manage the problem strategically

Better grazing and pasture management can limit the exposure of cows to parasites on pasture, Meusch said. Rotational grazing can allow cows to avoid times when the most larvae are emerging on the grass. Because the larvae remain lower in the grass surface layer to keep from drying out, leaving a higher residual when grazing can help avoid exposure to the larvae as well.

Strategic deworming is another concept that can help avoid exposure to parasite larvae on pasture. This is basically timing deworming treatments to take advantage of when the worms on the pasture are dormant and not reinfecting animals. When temperatures drop to 28 degrees Fahrenheit a few times, typically in the late fall, it can be a good time to deworm because it isn’t likely that cattle will be reinfected from the pasture after that point. This allows them to go through the winter without stomach worms, ensuring they benefit the most from supplemental feeding. It also ensures cattle aren’t depositing more eggs on the pasture over the winter.

The parasites infecting pastures will become active again in the spring when temperatures regularly exceed 50 degrees. As the eggs emerge into larvae and advance to the third stage, the cows will be infected again. The next strategic time to deworm is about six weeks after the springtime temperatures exceed 50 degrees. At this time, the cows will have been reinfected but are not yet depositing eggs in the pasture. This extends the time that eggs aren’t being deposited and helps reduce the parasite burden on the pasture.

It isn’t always possible to visually identify which cows are carrying the heaviest worm loads, but culling cows that chronically show symptoms of a heavy parasite infection can also benefit overall herd health.

“By managing grazing and strategically deworming cattle to avoid further pasture contamination, producers can keep their animals healthy and productive, as well as help ensure the long-term efficacy of deworming products,” said Meusch.

For more information about deworming strategies or assessing the worm load in your cow herd, contact your local MU Extension center, or email Eric Meusch at [email protected].

Fans of the Kansas City Chiefs, we and our team are the new villains in sports.

It is a good place to be. Somewhere between last years repeat Super Bowl win and this years opportunity to three-peat, we have stopped being Americas sweetheart, the plucky team with a history of heartbreak and disappointment.

Now, we’re the team that gets all the breaks. The NFL and the referees are being accused of rigging games in our favor. We are now what the New England Patriots were.

And it is wonderful. Sing along to the music of Queen, with altered lyrics:
“We are the villains, my friends.” This is where I could try to defend the Chiefs, especially against the ref accusations and Patriots comparisons. The idea that the officials as a group are trying to help the Chiefs win is ridiculous. Have some calls recently gone our way, especially in big moments? Of course. But if you’ve watched the Chiefs week in and week out, you know how many calls have gone against us or have not been made.

Mahomes has taken a number of hits that should have drawn flags and didn’t. The Chiefs were among the least penalized teams this season, but a year ago they were the fifth-most penalized team in terms of yards and 11th most in terms of number of penalties.

And unlike the early Patriots dynasty, we have not been illicitly taping our opponents practices, and our balls are not deflated. We don’t need to waste time defending our team against jealousy. Instead, let’s embrace our role as the NFL’s new villains. Our new motto: “Too bad.”

TV pundits are now debating how close Patrick Mahomes is to surpassing Tom Brady as the best quarterback ever. Mahomes is not even a Pro Bowl choice this season. He was pedestrian, at best, as the Chiefs won a record 11 games by one possession. The Chiefs have won 17 straight one-possession games.

Now that the playoffs have begun, Mahomes is back to looking like the best quarterback ever, Travis Kelce is revitalized, and the defense makes every play when it absolutely has to.

The Chiefs are no longer the circus act that can score 50 points in any game. Instead, they are the team that makes that one play to win a game, and avoids that one mistake that loses a game. They are business-like. They are a cat playing with its prey.
It may not be as exciting to watch for the casual fan, although the Chiefs are far more fun than the evil empire that was New England.

For K.C. fans of a certain age like me, every moment is appreciated. Many of these moments are also extremely stressful, because we are so traumatized by the team’s history. Between head coaches Hank Stram and Marty Schottenheimer, the Chiefs were irrelevant. The Chiefs had some great regular-season success under Marty and Dick Vermeil, but our playoffs were cursed after Joe Montana’s career ended with a concussion on the cold turf in Buffalo in the 1993 playoffs.

Then came a seven-year span where the Chiefs were a broken team, maybe the worst in the league. All of that made us very twitchy. This current run as the league’s best team was new territory for us as we still expected the worst to happen. But now, we are unequivocally the best team in the league. Can we be beat? Sure. But don’t bet on it.

It is time for us to be cocky. We should expect to win every game, and we should expect to get every call and every break. Bite my red-and-gold Andy Reid cookie. Let the hate flow through you. If you don’t like the Chiefs winning, tell your team to get better.
Until then, here is a bright yellow hankie to wipe away your tears. Go Chiefs!

Travis Mounts is managing editor of Times-Sentinel Newspapers in Cheney, a past president of the Kansas Press Association, and an ardent Kansas City Chiefs fan.