Dairy producers hoping to cut feed costs and stretch feed supplies may include more byproducts in their cows’ feed ration.
“The incorporation of some of the many byproducts available in our region is a good choice, but use some caution, not only because of the variability in nutrients inherent in byproducts but, in some cases, the loss of quality due to undesirable growing or storage conditions,” North Dakota State University Extension Service dairy specialist J.W. Schroeder says.
For example, excessive rainfall during the growing season or warmer than expected temperatures can lead to feed storage problems that result in spoilage (mold growth) and the development of mycotoxins such as zearalenone in wet distillers grain, sugar beet pulp and other byproducts. A mycotoxin is a toxin produced by mold, such as Fusarium fungi.
“Producers should be concerned because excessive levels of zearalenone could affect reproduction in sensitive species,” Schroeder says. “Because mold can develop in many wet byproducts if the conditions are right, I’m reminding dairy managers who use large amounts of byproducts to use caution this spring, especially for cows in the breeding pen.”
Zearalenone concentrations could be a particular problem when performing intensive techniques such as embryo transfer, especially in high-producing dairy cattle. NDSU and U.S. Department of Agriculture researchers note that intensive reproductive procedures such as embryo transfer would be more susceptible to the adverse effects of zearalenone and other mycotoxins than routine cattle breeding by bulls. Factors revealed during this case study suggested that mycotoxins at least could have contributed to reduced conception rates.
“The U.S. dos not have established tolerance limits for zearalenone in feed for livestock, but common sense when developing your feed ration goes a long way,” Schroeder adds. “If you are feeding a host of byproducts or feeding above the recommended amounts for any given byproduct, there always will be some risk when mycotoxins are present. Adding challenges to a cow’s diet is just one more potential impediment to her full-time job of producing milk and bearing a calf.”
Zearalenone in byproducts is not a new problem, and ruminants appear to be able to consume small amounts of feed with mycotoxins with no problems, research shows.
“However, while such feeding typically may present no risk to animal health, producers should be mindful of climatic and storage conditions that could increase the presence of these toxins,” Schroeder says. “I just want producers to be aware and use prudence when making changes to the dairy cow diet. And, if they are experiencing some shortfalls in herd reproduction, they should be sure to look at the whole picture, and when looking at the feed, watch for unwanted spoilage.”