According to Dr Norman Stewart, Manager of Livestock and Technical Services at Schering-Plough Animal Health, several hundred horn flies can be found on a single animal and they can pierce the skin and suck blood as often as 40 times a day.

Dr Norman Stewart, Manager of Livestock and Technical Services at Schering-Plough Animal Health

This results in blood loss, reduced weight gain and feed efficiency and reduced milk production.

A field trial, conducted by veterinary products manufacturer Schering-Plough, set out to evaluate the efficiency of a new product, ULTRA SABER pour-on, by comparing it to three other insecticidal pour-on products against natural horn fly, Haematobia irritans, infestations on cattle in South Florida.

The products for comparison were a generic Ivermectin pour-on, a generic Lambdacyhaothrin pour-on, and a 7.4 per cent Permethrin with 7.4 per cent Piperonyl Butoxide pour-on.

Animals and Procedures

The test used two herds of cattle on farms more than three miles apart from each other in South Florida.

Treatment Groups
I. ULTRA SABER (1% Lambdacyhalothrin and 5% Piperonyl Butoxide)
II. Exile - a generic Lambdacyhalothrin pour-on - (1% Lambdacyhalothrin)
III. Agri-Mectin® - a generic Ivermectin pour-on - (5 mg. Ivermectin/mL)
IV. Fly Ban™ - (7.4% Permethrin with 7.4% Piperonyl Butoxide)

One herd had approximately 562 head of two-year-old heifers, and one herd had approximately 560 head of yearling heifers.

A total of 420 head of the two-year-old heifers, each weighing approximately 800 lbs, were equally allocated across treatments I, II and IV.

Another 440 head of the yearling heifers, which weighed approximately 770 lbs. each, were equally allocated across treatments I, II, III and IV.

All cattle in a herd, based on their respective treatment group, received a single treatment applied on Study Day 0. All products were administered in accordance with label directions.

Treatment III was not evaluated in two-year-old heifers.

Fly counts were conducted before treatments were applied and on a weekly basis during an eight-week period for both herds.

For each herd (yearling heifers and two-year-old heifers), 15 animals were randomly selected from each treatment group, and horn flies were counted on each animal by use of binoculars.

For these 15 head, the average horn fly count by treatment and by week are listed in the tables in the Results and Discussion section.

Yearling Heifers

In the yearling heifer group, the number of flies before the treatments were applied were calculated to be 617 per head.

In this group all four insecticide treatments were used - Ultra Saber, Exile, Agri-Mectin and Fly Ban - at label dosages.

At the end of the first week, Schering-Plough found that ULTRA SABER reduced fly pressure by 99 per cent. At the end of week three it had reduced fly pressure by 98 per cent and by the end of the trial, week eight, it had reduced fly pressure by 87 per cent.

Schering-Plough said that economic thresholds, adjudged to be 100 flies per head, were not reached in the ULTRA SABER treated animals during the 8-week evaluation.

Schering-Plough added that Throughout the eight-week trial, on average treatment II had 29 per cent more flies than ULTRA SABER treated animals; treatment III had 76 per cent more flies than ULTRA SABER treated animals and treatment IV had 60 per cent more flies than ULTRA SABER treated animals.

Two Year Old Heifers

In the study on the two year old heifers, the herd of 420 cattle had 542 flies per head before treatments were applied.

The test evaluated ULTRA SABER, Exile and Fly Ban at label dosage.

Schering-Plough said that throughout the eight week trial on average both Fly Ban and Exile had 21 per cent more flies than ULTRA SABER treated animals.

"ULTRA SABER consistently provided exceptional reduction in fly pressure throughout the eight week evaluation," Dr Stewart concluded.

February 2008