New cattle feed test streamlines process

by Todd Neeley
A promising new test designed to detect cholesterol in animal feed may soon become a tool in the battle against mad cow disease. In an article to be published in the coming months by the scientific journal Rapid Communications in Mass Spectrometry published by John Wiley and Sons, a USDA Agriculture Research Service study conducted by a research chemist in Albany, CA, cholesterol was detected at higher levels in animal feed components that contained animal-based products. Study author Christopher J. Silva told DTN if the test passes a peer review among members of the scientific community, FDA field workers could use the method to narrow large numbers of animal-feed samples while testing for prohibited animal proteins. In an age when U.S. producers and consumers are concerned about mad cow disease making its way into the food supply, he said, the new test could be an important marketing tool for producers. "If you can show that the feed you are feeding cows is vegetable feed," he said, "then people eating meat can feel more comfortable. If there are animals identified to a particular farm, it might be nice to say to your customers that your animals were fed with a certain feed. There's a perceived value in this. I see it as a consumer protection issue more than a regulatory issue." Because the technology could be expensive to make available to farmers, Silva said, chances are government regulators and larger feed-rendering companies would be more likely to use such a test. In developing the cholesterol method, he studied three complex feed mixtures obtained from various commercial feed companies across the country. One mixture contained soybean oil and the other two had animal vegetable fat added, he said. Silva said he found cholesterol in all of the feeds. Plant-based feeds typically contain much lower levels of cholesterol than do animal-based feeds, he said. The study established what would be a "typical" level of cholesterol in plant-based feeds — a level that does not necessarily indicate the presence of animal cholesterol. In the feeds that contained animal vegetable fat, however, overall cholesterol levels were three to five times higher than in plant-based feeds, Silva said. "My scientific background was looking at sterols (cholesterol)," he said. "I thought it was an obvious thing. Most tests are antibody based. I wanted to look at real samples instead of making it in a laboratory." While researches continue to look for a way to test for prion proteins in animal feed, the prime transmitter of BSE that is found in blood and ruminant organs and spinal tissue, the first-of-a-kind cholesterol test method could be a step in safeguarding animal feed and ultimately the U.S. beef supply, Silva said.