Specific profile of fatty acids in feed may trigger variable outcomes in dairy cattle, researchers say
Global researchers say it’s time for attitudes about dairy feed fat content to follow current trends in protein: The inclusion of specific fatty acids may matter more than overall fat content.
According to a meta-analysis by Michigan State University, experiments in changing the fatty acid profile of dairy feed produces varying effects on dairy cattle performance. Supplements comprised of 80% palmitic acid and 10% oleic acid typically boost milk production, but at the expense of body condition, according to Adam Lock, an associate professor in the Department of Animal Science at Michigan State University. However, feeding a blend of 60% palmitic acid and 30% oleic acid maintained the improved milk production, without triggering weight loss.
“We need to move away from talking about fat, to fatty acids, the same way we moved away from talking about cured proteins,” Lock said during an August 6 virtual press briefing.
Cows fed diets high in palmitic acid in the first three weeks after calving produced an additional 5 kilograms of milk during one Michigan State study, Lock said. However, they lost 30 kilograms in body weight over the same period of time. The cows fed the more balanced palmitic-oleic blend gave the same amount of milk, but did not experience the weight loss.
“If we get these blends correct, we can have the best of both worlds,” Lock said. “We can improve milk yields without sacrificing body weight.”
The effect of both diets persisted after the initial three-week period, even if the fatty acid supplementation was discontinued during the peak production period. Milk production increased by 8% during supplementation, and remained 7% higher than the control group after supplementation ceased, according to John Newbold, a professor of dairy nutrition at Scotland’s Rural College.
“This raises some really interesting questions about biologically what that fat supplement is doing,” he said.
While more research is necessary to understand these effects, Lock encouraged producers to pay closer attention to the fatty acid profile of their dairy feed, rather than simply feeding byproducts.
“Many commercial products out, simply took byproducts from other industry and utilized them as a fat supplement,” he said. “Now they’re starting to make specific fatty acid products.”
Another critical element of fat supplementation is how the fats are delivered, according to Richard Kirkland, global technical manager for Volac Wilmar Feed Ingredients. Raw ingredients like rapeseed or soybean oil can coat bacteria in the rumen and prevent the digestion of fiber, essentially making these ingredients toxic to ruminants. But fatty acid supplementation can be achieved by delivering fats in rumen-protected calcium salts.
“We don’t feed fat, we feed fatty acids,” he said. “This is where the new research is coming into focus in terms of what we can learn and specific targets for dairy farms.”