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 Everglades Station Mimeo Report EES65-24 April 1965

 THIABENDAZOLE: A CATTLE DEWORMER /
 C. E. Haines /


 For many years, cattlemen have depended on phenothiazine a, e
 main anthelmintic material for their cattle. However, a search
 continued for a material that will be more effective against a gr tk
 er variety of internal parasites and also be more palatable than ph
 thiazine. A new material (thiabendazole) that may meet these require-
 ments for an anthelmintic is now available. To test the anthelmintic
 properties of thiabendazole, a group of crossbred yearling steers were
 used at the Everglades Experiment Station.

 Procedure

 Eighty steers of Angus x Hereford x Brahman breeding were divided
 into four equal groups of 20 animals. Each group received a different
 rate of a concentrate mixture continuously while grazing on Roselawn
 St. Augustinegrass pastures. Half of the steers in each nutritional
 treatment were given thiabendazole at the rate of 3 grams per hundred
 pounds of body weight. The material was administered by drench in
 November, December, January and February. A month prior to the ini-.
 tial test treatment, all steers in each group had been drenched with
 phenothiazine.

 The steers had an average weight of 543 pounds at the beginning
 of the trial. The initial parasitic populations as measured by the
 number of eggs per gram of feces (EPG), showed.some variations between
 anthelmintic test groups within the nutritional treatment groups. This
 resulted from the procedure of allotment by weight prior to parasitic
 infestation determinations. The overall average initial number of EPG
 was 143 for the treated groups compared to 172 EPG for the non-treated
 groups. Animal weights and EPG counts which were obtained six months
 after the initial administration of thiabendazole were used for deter-
 mining its' effectiveness.

 Although thiabendazole may be cheaper if purchased in large quan-
 tities through certain commercial companies, the local retail price is
 approximately $0.08 per gram. To present this information so that it
 might be suitable for all sizes of cattle operations, the higher cost
 of $0.08 has been used in computing the economical aspects of the anthel-
 mintic treatment. Since each steer received from 15 to 18 grams of the
 material per treatment, the cost of each treatment was between $1.20. and
 $1.44 per steer. Thus, by using an average figure of $1.32 per treat-
 ment and a total of four treatments per steer the total cost of the test


 / Thiabendazole supplied by Merck Sharp and Dohme, Research Laboratories,
 Rahway, N. J. The trade name for thiabendazole is Thibenzole (TBZ).

 Assistant Animal Husbandman, Everglades Experiment Station, Belle
 Glade, Florida.