March 6, 2007

US approves Nuflor premix for swine
 

The US Food and Drug Administration (FDA) recently licensed Nuflor (florfenicol), an antibiotic for the control of swine respiratory disease (SRD).

Used extensively in other countries, Nuflor Premix was introduced to the US market as the country's pork industry lacked a broad-spectrum, feed-grade antibiotic that would enable mass-medication for control of SRD, which remains a leading cause of economic losses for pig producers, says Dr. Robyn Fleck, Manager, swine technical services for Schering-Plough Animal Health.

Schering-Plough Animal Health conducted six clinical field trials with Nuflor Premix at locations in Iowa, Minnesota, Nebraska, South Dakota and Indiana. The trials involved more than 1,100 sick pigs with SRD. Investigators treated the pigs for 5 days then evaluated them for 2 days after treatment stopped. They recorded temperatures and scored pigs for depression and dyspnea (breathing difficulty). The success rate in pigs receiving Nuflor Premix was more than 75 percent, significantly better than the 51 percent rate in untreated controls.

Pigs receiving Nuflor premix also grew twice as fast during the treatment and evaluation period, producing an average daily weight gain of 0.665 kilogrammes compared to 0.3353 kg in untreated controls. Cumulative mortality for the group receiving Nuflor Premix (4.4 percent) was less than half the mortality of the controls (9.7 percent), Fleck says.

While pigs receiving Nuflor had a higher incidence of loose stools, perianal inflammation and rectal eversion compared to controls, the side effects were transient and did not have a significant impact on pig health or performance, as demonstrated by better survival and weight gain, she says. Bacteria isolated from the clinically ill animals included Actinobacillus pleuropneumoniae, Pasteurella multocida, Streptococcus suis and Bordetella bronchiseptica, Fleck says.

Trials also have shown that Nuflor Premix is highly palatable and can be incorporated into pelleted feeds. Furthermore, studies show that florfenicol is quickly absorbed, reaching therapeutic concentrations in serum within 4 to 5 hours. In the clinical trials, florfenicol concentrations remained above target level for 18 to 20 hours for each of the 5 treatment days.

Nuflor Premix for Swine is the second oral formulation of florfenicol to become available to the US pork industry. Last year, Schering-Plough Animal Health introduced Nuflor2.3 percent Concentrate Solution, a water-soluble formulation for use in pigs' drinking water.