January 4, 2017

Nutriad: erratic weather in 2016 raised mycotoxin levels across US

Varying weather patterns across the US during the 2016 growing season provided ideal conditions for the development of deoxynivalenol (DON) and aflatoxins (AFB1) in corn crops, posing a threat to feed quality, says Nutriad.

Dryness during pollination, due to mild to severe drought conditions across the plains and southern states was a major cause in aflatoxin levels. According the Neogen Mycotoxin Report, confirmed reports of mycotoxins were found in Kansas, Oklahoma, Texas, Louisiana, Alabama, Georgia, South Carolina and North Carolina. The most severe cases were found in Texas with corn testing above 150 parts per billion (ppb) and in North Carolina above 200 ppb. According to the US Food and Drug Administration, feeds may not exceed more than 20 ppb of AFB1 or 0.5 ppb of AFM1 to dairy cows before milk must be discarded. AFB1 can cause a number of symptoms in dairy cows ranging from a decrease in feed intake, an increase in somatic cell count to lowered milk production, ultimately affecting profitability.

The Neogen Mycotoxin Report also indicated reports of high DON levels across the plains and northeast states in both the corn and wheat crop due in part to excess rain during late summer and fall. Confirmed reports were found in Nebraska, Iowa, Wisconsin, Illinois, Indiana, Ohio, Michigan, Pennsylvania and New York ranging from three to more than five ppb.

According to Wendy Vandenboom, Nutriad mycotoxin specialist, mycotoxins can have many effects on dairy cows - from simple feed refusal resulting in a lack of nutrition to serious detrimental effects on the body. Cows can suffer reproductive problems such as poor heats, infertility or embryonic losses. Milk production can also decline significantly. Intestinal health can be compromised as well, compounding nutritional deficits. In severe cases, mycotoxin ingestion can also lead to mortality.

"In addition, we are seeing these high levels of mycotoxin in silage stalks, soybean stubble and even some straw," says Vandenboom. "When these products are used for bedding, we have to be aware that the cows will often eat this as well, which means we have to account for possible mycotoxin ingestion in all cows including neonatal calves."

Neonatal calves are often overlooked when we are dealing with mycotoxin exposure because the usual sources of contamination are forages. When mycotoxin levels are as high as reported this year, calves must also be assessed and managed for mycotoxin effects as they can become more susceptible to the risk of diseases caused due to a less developed immune system. Ingestion of mycotoxins can also impair growth rates in calves as their dry matter intake decreases.

Steps involved in dealing with mycotoxins should include: testing and analysing feedstuffs for the presence of mycotoxins; practising proper feed and storage management strategies to minimise ingestion levels; utilising mycotoxin management solutions proven to not only minimise the effects on cows, but also to aid in the recovery and healing due to the damages already done.

As another harvest season is now complete, dairy producers are looking towards the quality of their crops during winter storage months.

"Mycotoxins can increase over time if feeds are not stored properly. Producers should utilise mycotoxin identification tests to help determine specific sources of contamination to allow for a tailored response to meet the needs of individual herds," suggests Vandenboom.