Fighting Summer Parasite Risks with Safe-Guard®

Cheyenne Rathe & Heather Kime

Jun 06, 2024


Internal Parasite Risks During Summer

The weather has warmed up and most ranchers have kicked cattle out to grass for the summer. While this may be a less labor-intensive time of year, there are still some management decisions that should be considered to ensure optimal health and productivity of the herd. One of the biggest threats that cannot always be seen with the naked eye is damage caused by internal parasites.

When animals pick up and ingest parasites from an infected pasture, these parasites first cause damage by burrowing into the lining of the gastrointestinal (GI) tract. This causes discomfort and greatly suppresses appetite. The resulting diseased and damaged GI tract reduces the animal’s ability to absorb nutrients putting stress on the immune system, increasing the energy demand to drive the immune system, and leaving the animal susceptible to other diseases like pink eye, cocci, and other viruses that can lead to increased vulnerability to bacterial infections. Producers can see these effects by a decreased rate of growth, milk production, immune function, and reproductive function. Calves are even more susceptible because they haven’t had a chance to build up a full immune system yet.

Combating Parasites with Safe-Guard®

Safe-Guard® (fenbendazole) is administered orally and goes directly into the GI tract to kill internal parasites. It works by attacking the energy metabolism function of the parasite, depleting the energy resources in the parasite, and essentially starving them to death. Because of its unique characteristics, Safe-Guard® can be ingested by the worm but not excreted, allowing Safe-Guard® to accumulate to a lethal dose. When cattle are administered a one-time dosage, the accumulated Safe-Guard® reaches a lethal level within 24 hours. Cattle getting Safe-Guard® from a mineral supplement over 3-6 days, and only getting a partial dose every day, will still accumulate to a lethal level and kill the internal parasites.

Strategic deworming is the use of dewormers to interrupt the life cycle of parasites by allowing the cattle to consume infective larvae while grazing, but timing treatment to kill these parasites before they mature into egg-laying adults and begin producing eggs within the animal. Mitigating risk due to internal parasite load, Safe-Guard® can benefit cattle by increasing intake, weight gain, weaning weight, and conception rate. Proven results from research trials include:

  • An average increase of 37 pounds of gain on stocker steers
  • An average increase of 29 pounds heavier weaning weights
  • An average 7% increase in conception rates


To evaluate current parasite load and success from deworming, producers can use a Fecal Egg Count Reduction Test (FECRT). Contact your CVA rep for assistance with obtaining a kit or visit

Administering Via Pellets and Range Cubes

Central Valley Ag manufactures both pellets and range cubes containing Safe-Guard® for easy and convenient dosage and administration in a one-time feeding without the need to run cattle through a chute. Both pellets and cubes are available at a dose of 1 pound of feed per 600 pounds of body weight.

For the treatment and control of: Lungworms: Adult Dictyocaulus viviparus; Stomach worms: Adult brown stomach worms (Ostertagia ostertagi), Adult and fourth stage larvae barberpole worms (Haemonchus contortus), fourth stage larvae barberpole worms (H. placei), and Adult and fourth stage larvae small stomach worms (Trichostrongylus axei); Intestinal worms (Adult and fourth stage larvae): hookworms (Bunostomum phlebotomum), thread-necked intestinal worms (Nematodirus helvetianus), small intestinal worms (Cooperia punctata & C. oncophora), bankrupt worms (Trichostrongylus colubriformis), and nodular worms (Oesophagostomum radiatum).

Not for use in beef calves less than 2 months old, dairy calves and veal calves. Cattle must not be slaughtered for human consumption within 13 days following the last treatment of Safe-Guard®. In dairy cattle, milk discard time is 60 hours.

Stop by and see the CVA Feed team at the 2024 Sandhills Ranch Expo in Bassett, NE June 19-20 where we will kick off with a promo on Safe-Guard®! Purchase $500 worth of Safe-Guard® products and receive co-branded CVA/Merck apparel. Products include cake, pellets, pastes, drenches, and blocks. Promo valid on purchases made June 19-28, 2024.

Contact your local sales representative or stop by a CVA location to get your Safe-Guard® products today!

  • Spencer Shifflet | Ainsworth, NE | (308) 883-0949
  • Nathan Bracht | West Point, NE | (402) 380-0826
  • Merlin Schlote | Elgin, NE | (402) 649-9383
  • Justin Tracy | Gordan, NE | (308) 962-4255


Heather Kime | Merck Animal Health

How Internal Parasites Affect Cattle Immunity | Merck Animal Health

Benefits of Summer Deworming for Cattle | Merck Animal Health

How to Deworm Beef Cattle & Maximize Performance | Merck Animal Health

SAFE-GUARD® Cattle Dewormer | Merck Animal Health