Bayer Releases Study Results on Performance of Zelnate® DNA Immunostimulant

Bayer Animal Health announces results from a clinical field study for the performance of Zelnate DNA Immunostimulant on arrival with modified live viral (MLV) vaccine on arrival or delayed.

Goals for the study were to examine how Zelnate may improve health and performance outcomes when used on arrival, and to observe the potential benefits of delaying the MLV vaccine until after initial stress and Mannheimia haemolytica challenges are experienced.

Key study results are as follows:

  • At the conclusion of the study, Zelnate significantly reduced overall mortality at every measured time frame (60 days, 116 days and close-out), regardless of whether the MLV vaccine was administered on arrival or MLV delayed 30 days.
  • Zelnate significantly reduced BRD mortality at 60 days (with a 30.2 percent reduction in total mortality and a 28.4 percent reduction in BRD mortality) and 116 days (with a 31.5 percent reduction in total mortality and a 27.5 percent reduction in BRD mortality) compared to calves not treated with Zelnate. Zelnate followed the same trend at close-out.
  • Although not statistically significant, Zelnate showed a trend in reducing the BRD case fatality rate throughout the study.
  • Delaying the MLV significantly reduced second BRD treatments at all three time frames, and significantly reduced BRD re-treatment risk at 116 days and close-out.

“Because BRD remains such a challenge in the cattle industry, Bayer is focused on finding new and innovative ways to attack this devastating disease,” says Jim Sears, senior technical services veterinarian, Bayer Animal Health. “That includes looking at how recently developed products, such as Zelnate, can be used in different ways and at different stages in a producer’s BRD prevention and treatment protocol.”

The study included a total of 5,179 crossbred heifer calves at a commercial feedlot in southwest Kansas and looked at whether multiple biologicals in the arrival processing of medium to high risk cattle in a feed yard may be causing undue levels of stress and compromising the immune system. The primary BRD challenges faced by such cattle in the early stages of their feeding period are usually associated primarily with or caused directly by Mannheimia haemolytica infections.

“Overall, we saw an added value of including Zelnate in processing cattle, with Zelnate consistently improving survivability, resulting in a 22 percent reduction in overall death loss, regardless of on arrival or delayed processing,” says Sears.

“These study results remain consistent with prior studies in demonstrating how Zelnate reduces mortality in cattle herds.”

For more information or to obtain a copy of the report, call Bayer Veterinary Services at +1 (800) 422-9874 or visit