01022019_tct_bw_cows_feeding

Mycotoxins present themselves in a variety of ways after cows consume feed containing them.

Farmers need to continue keeping a close eye on the prevalence of mycotoxins, Alltech representatives Dr. Max Hawkins and Pat Crowley said recently during a December corn silage update.

Hawkins, a nutritionist with the Alltech Mycotoxin Management team, said the 390 samples processed at the Alltech Analytical Services Lab reveal an average of 6.57 mycotoxins per sample. Overall, 99 percent of the sample contained multiple mycotoxins.

Mycotoxins, produced by certain mold species, impair optimal livestock performance by affecting intestinal, organ and immune systems, which in turn can reduce profitability.

This year’s historically wet conditions, especially in September and October, negatively impacted portions of numerous states, particularly Wisconsin.

“As we get into the Upper Midwest, the Great Lakes area, out into the East, our risk is pretty steadily moderate to high risk as we get into corn silages,” Hawkins said.

He noted that the percent of corn silage samples at higher risk REQ (risk equivalent quantity) is 63.6 percent for dairy cows, 85.6 percent for calves/heifers and 53.6 percent for beef cattle.

Crowley, an on-farm specialist at Alltech with nearly 25 years of dairy industry experience, said symptoms of mycotoxins may include:

  • Digestive disorders, such as intestinal damage/hemorrhaging, inconsistent manure or changes to gut microbial populations.
  • Immunity health, in the form of increased somatic cell count, suppression of immunity, low pathogen resistance and increased health treatments.
  • Reproduction, notably with altered heat cycles and infertility/poor conception.
  • Production, evident in lower milk yield, decreased growth rates, reduced longevity and reduced profitability.

Crowley spotlighted four mycotoxins of particular interest:

  • Type B trichothecenes: They can result in digestive disorders, poor rumen function, loose and inconsistent manure, poor production and spit up cuds. Crowley encouraged looking for spit up cud in beds. “Spit up cuds are a classic sign of very high vomitoxins,” he said.
  • Type A trichothecenes: Among the problems are bloody diarrhea, digestive upset, immune suppression, increased somatic cell count and intestinal hemorrhaging.
  • Zearalenones: Concerns include irregular heats, infertility/poor conception rates, abortions, embryo mortality and cystic ovaries. “Zearalenones are really going to affect the reproduction side of your dairy,” Crowley said.
  • Penicilliums: They can result in increased feed refusals, decreased production, poor rumen function, decreased milk components and poor immune response.

Hawkins pointed out that of the 390 samples, 17.4 percent had five mycotoxins, 14.6 percent had seven mycotoxins and 14.1 percent had six mycotoxins. The highest occurrence of mycotoxins was fusaric acid at 97.9 percent, followed by type B trichothecenes at 93.3 percent.

In addition, he said they’re seeing higher-than-normal occurrences of type A trichothecenes (39.2 percent) and zearalenones (14.4 percent).

“We’re not seeing as prevalent with penicilliums as we thought we might with some of the crop challenges,” Hawkins said. “But a lot of the silage facilities have not been opened up yet (so) that story has not been fully told yet.”

Regarding high moisture corn, Hawkins said 66 samples indicate an average of 7.48 mycotoxins per sample.

“We’re probably seeing some fermentation issues going on,” he said. “We may have more oxygen penetration. The zearalenones can certainly lead us down the road to some reproductive issues. So we really want to monitor this high moisture corn moving forward.”

Crowley discussed identifying challenges in the bunker/pile. Factors influencing molds/mycotoxins include temperature, oxygen and water content, pH, packing density, storage quality and usage rate.

“Sometimes these mycotoxins and these molds are just going to be plain as day,” Crowley said. “You’re going to see it on the ground from facing, or you’re going to see spots of it on the bunker face. It’s going to be pretty apparent. But sometimes they’re not.”

Thermal image cameras are one device he uses to reveal warmer spots in the bunker/pile. Those areas of extra heating allow mold and yeast to grow.

“We really want to start walking those pre-fresh, post-fresh groups,” Crowley said. “These are the cows that probably have the most stress in the barn and are going to be affected quicker to a mycotoxin event than anyone else.”