A large portion of the pathogens and toxins found in the gastrointestinal tract come from the total mixed ration (TMR). These detrimental organisms and compounds can contaminate feed in the field, during feed storage and feed-out, or throughout the course of feed mixing and delivery.
The “bad actors” threatening feed hygiene come in many different forms:
Clostridia frequently contaminate forages and their populations have been found to grow in the TMR over time. They are everywhere in the environment. In fact, ARM & HAMMER has analyzed 30,000 fecal samples and 7,000 feed samples across the country for clostridia and other detrimental organisms. Of the samples analyzed, 98.6% of fecal samples and 84.7% of feed samples contained detectable clostridia. This same survey also found that 78.5% and 33.6% of fecal and feed samples, respectively, contained C. perfringens, a toxin-producing clostridia known to contribute to hemorrhagic bowel syndrome (HBS) in dairy cattle.
Salmonella and E. coli, when found in silages and the TMR, suggest poor silage fermentation or manure contamination during feed out, feed mixing, or delivery.
If spoilage occurs in forages, high levels of yeasts and molds can end up in the TMR. Yeasts and molds can steal valuable nutrients from the cow and may cause inconsistent intakes or impact performance. Mycotoxins are secondary metabolites produced in feeds by various species of molds. Although the rumen microbial community is able to detoxify many different mycotoxins, a dairy cow’s high rate of feed intake and feed passage out of the rumen make it unlikely for complete detoxification of mycotoxins that find their way to the small intestine.
Improving Feed Hygiene
A number of valuable strategies exist that allow producers to either limit a cow’s exposure to pathogens and toxins, or to control the pathogens and toxins that end up in the gastrointestinal tract.
Optimizing silage fermentation is the first step in limiting a cow’s exposure to pathogens and toxins. The fast, thorough acidification typical of a high-quality fermentation creates an environment in the silage pile that is detrimental to the growth of many different pathogens.
Yet even when silages are properly fermented, contamination of clean feed can still occur during silage feed out, feed mixing, and delivery. Here are 10 easy steps to help minimize feed contamination on-farm:
1. Clear debris and spoiled silage off silage pads and feed areas.
2. Increase silage feed-out rate and immediately feed defaced silage.
3. Feed high-moisture byproducts quickly, emptying bays before restocking.
4. Keep feed alleys free of debris, scraping at least once daily.
5. Clean feed bunks, especially directly under headlocks.
6. Keep waterers clean and clear.
7. Feed refusals as soon as possible. Mix batches containing refusals last.
8. Thoroughly clean the TMR mixer once per month.
9. Clean pushup blades monthly.
10. Clean tires and buckets of all feed payloaders and skid loaders. Avoid handling feed with buckets that have moved manure or dirt.
Inside the Cow
Despite your best efforts, pathogens and toxins inevitably enter the cow. Bacillus technology can inhibit clostridial populations in the gastrointestinal tract and improve hindgut integrity, while refined functional carbohydrates (RFCs) effectively bind pathogens and mycotoxins in the gastrointestinal tract.
A field study involving 77 dairies and 230,000 cows across 18 states found that feeding Bacillus reduced the risk of clostridia and C. perfringens challenges. Bacillus feeding resulted in an 89% increase in the number of fecal samples classified as low risk for clostridia challenges, and a 13% decrease in the number of samples classified as high risk. Looking specifically at C. perfringens, feeding Bacillus resulted in a 20% increase in the number of low-risk fecal samples and a 26% decrease in the number of high-risk samples.
Regarding the effect of RFCs on pathogen binding, specifically Salmonella and E. coli, a study found that E. coli F18 as well as S. Newport, S. enteritidis, S. Dublin and S. cholerasius were all effectively bound in the presence of RFCs.
In another study, RFCs were found to effectively bind mycotoxins, resulting in a significant reduction in epithelial cell damage due to the mycotoxins Aflatoxin, T-2, DON, Zearalenone and Fumonisin B1.
Limiting a dairy herd’s exposure to pathogens and toxins is critically important to achieving consistent productivity and profitability. Taking the necessary steps to improve feed hygiene on-farm and reduce the negative impact of pathogens and toxins in the gastrointestinal tract is essential for improving the overall health and resilience of the dairy cow.
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