Internal Parasites

Another important factor in the overall health of a beef cattle herd is that of internal parasites.  In order to assure adequate weight gain of cattle along with overall health and hardiness, producers need to implement a thorough program in order to eliminate these parasites.  Similarly to the vaccination program, many choices are available when it comes to deworming programs.  A deworming schedule and program should be tailored to meet each producer’s needs in their respective locations and situations, just as in the vaccination program.  Veterinarians should be consulted for factual and profitable deworming programs throughout various regions of the state.  The following programs are a compilation of 2 programs from Steven E. Wikse, DVM and Thomas A. Craig, DVM, both from the Texas Veterinary Medical Center at Texas A&M University.

Spring Deworming-(Mid March)
(yearlings only)
Strategy: Give the young animals that are most susceptible to O. ostertagia an extra deworming just prior to the breeding season to lower their worm burden during that time. Drugs with effectiveness against immature stomach and intestinal worms are adequate.

Animals: Stockers, yearling replacement heifers and first-lactation heifers.

Anthelmintics: Fenbendazole (Panacur®, Safeguard®), Oxyfendazole (Synanthic®), Albendazole (Valbazen®), Ivermectin (Ivomec®, Ivomec-SR Bolus®, TopLine®, Double Impact®), Doramectin (Dectomax®), Moxidectin (Cydectin®), or Eprinomectin (Ivomec-Eprinex®) at regular doses.

Summer Deworming-(Mid-June to Mid-July)

(cows, bulls, and calves)
Strategy: Kill the population of arrested O. ostertagia larvae that have accumulated in the wall of the abomasums during the late spring to prevent abomasal damage from their later emergence (Type II Ostertagiasis) and to prevent their development into egg-laying adults that contaminate the pasture.

Animals: All cattle on the ranch weighing 250 pounds or more.

Anthelmintics: Albendazole, Doramectin, Eprinomectin, Ivermectin, Moxidectin, or Oxfendazole at regular doses. Fenbendazole at the increased dosage (10mg/kg) in younger cattle. The above drugs vary in their efficacy against arrested O. ostertagia larvae.

Fall Deworming-(November or December, after killing frost)
(cows, bulls, and calves)
Strategy: The fall reinfection with O. ostertagia during September and October will be completed, and the worms will be present mainly in the adult stage. Their removal will lessen pasture contamination and may help the animals maintain body condition during the winter feeding period. Liver flukes will have matured into adults by then and will be susceptible to available anthelmintics.

Animals: All cattle on the ranch weighing 250 pounds or more.

Anthelmintics: Fenbendazole, Oxfendazole, Albendazole, Ivermectin, Doramectin, Moxidectin, or Eprinomectin at regular doses for O. ostertagia. Albendazole or Ivermectin plus Clorsulon (Ivomec F®) at regular doses for flukes.

The above programs are to be used as a reference guide in order to ensure the overall health of a beef cattle herd. A veterinarian should be consulted when beginning a vaccination or deworming program to ensure the relativity and effectiveness of the program within a respective area.

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