With the 2014 harvest on the near horizon, many pork producers are finding the last of the 2013 grains being used in feed are of substantially lower quality. Even when stored in the best conditions, grains never improve in quality during the storage period. Grain quality is either maintained or lost, taking with it the farm’s net returns.
“The quality of stored grains depends on many different aspects, and it starts in the field by choosing the hybrid to be planted, density of plants, tillage management and weather conditions,” says Guilherme Bromfman, North American mycotoxin management manager at Alltech. “Post-harvest, there are also key factors such as air management, insect control, moisture of grains, rodents, molds and weather conditions during storage.”
According to Bromfman, it is imperative that grains are stored at 13 percent moisture or less, however even if dried to that level, there is a risk for moisture absorption as the hygroscopic equilibrium (the ability of a substance to attract and hold water molecules from the environment) of the corn fluctuates based on temperature and relative humidity. The movement of the moisture inside silos or bins generates “hot spots,” small areas with higher moisture and an increased incidence of molds that, through respiratory process, elevates the temperature.
“When a higher mold incidence occurs, there are two key challenges: first is the reduction of nutritional values and the other is a higher frequency of mycotoxins,” says Bromfman.
Mycotoxins can reduce weight gain in pigs, increase feed conversion and shrink net returns per animal. Bromfman advises producers to be aware of these specific mycotoxin symptoms in pigs:
Type B Trichothecenes (DON): Long-term exposure of low levels of DON results in lower feed efficiency and immunity. Moderate risk levels of DON reduce feed intake and efficiency, and cause pigs to be lethargic. DON can also have a strong impact on gut health, causing damage to the intestine and reducing nutrient utilization.
At high risk levels, the toxin can alter brain neurochemistry, leading to a severe decrease in feed intake, lethargy and vomiting. Together, these can result in weight loss. DON also causes damage to internal organs such as the intestines and liver, causing lesions and hemorrhages.
As we get closer to harvest, when the last of the “old” corn is used in the diets, it is crucial to have a mycotoxin management program in place. A number of companies and laboratories are available to analyze feed contamination and manage potential risks in the feed mill and in production facilities to minimize the impact low-quality grain can have on livestock performance and profitability.
The total risk to animals, based on the particular mycotoxin load in a given sample, is quantified by the Risk Equivalent Quantity (REQ) – one number which summarizes the overall challenge posed to the particular species. The REQ level for swine increased over time from harvest in September 2013 to May 2014. The increased REQ levels show how storage can affect quality of grains and the importance of implementing a continuous program for mycotoxin management.