One of the sweetest ways to maximize dairy cow profitability may be by adding sugar to the ration.
In some cases, high-sugar co-products like candy meal, citrus pulp, and whey may be available at bargain prices or serve as “rescue” TMR ingredients when growing or storage conditions of traditional feedstuffs are poor. In other situations, strategically balancing the ration with high-sugar ingredients like molasses can help create the perfect rumen environment for fermentation, fiber digestion, and milkfat and protein synthesis.
Former Penn State University Dairy Extension Specialist Virginia Ishler said adding sugar to the ration can change up the carbohydrate profile and take some of the pressure off of starch as the only energy source to maintain production and components. And because cows, like people, love the taste of sugar, it also can promote dry-matter intake – particularly in the critical transition period -- and minimize sorting.
Navigating the delicate dance between capturing the benefits of sugar and protecting the rumen environment was discussed at length on a recent episode of The Dairy Podcast Show. Dr. Andy Mueller, North Region Technical Service and Sales Specialist for Westway Feed Products.
Sugars disappear in the digestive process faster than starch, which creates some concern for ruminal acidosis. But Mueller explained that while they both supply carbohydrates, sugars and starches feed completely different microbial populations in the rumen.
“You have your amylolytic bugs, which digest starch and produce propionate, and you have fibrolytic bugs, which digest sugars,” he stated. “So, the bugs that use sugars are the same ones that digest fiber, and when sugars ferment, they make acetate and butyrate.”
Those two volatile fatty acids do not convert readily to lactic acid, the usual culprit in ruminal acidosis. Instead, butyrate serves as an energy source to the rumen, and acetate is the precursor for butterfat production.
He added that protozoa and fungi in the rumen also love to feed on sugar. As they grow, they crack open the outer cuticle layer of fibrous feedstuffs, which accelerates fiber digestion. “Sugars ferment quickly, and they’re gone quickly, but the way they ferment, they don’t reduce rumen pH or cause acidosis,” Mueller explained. “They actually support your fiber degraders and help increase butterfat production.”
The nutritionist said adding or swapping in sugar may help kick-start rumen fermentation and maximize rumen function in a variety of nutritional circumstances. Examples include a very high-starch (32-33%) ration; when butterfat production levels are struggling; and rations that are low in rumen-degradable protein.
Lowering starch levels by subbing in sugars should help support higher rumen pH, which supports biohydrogenation that converts unsaturated fats to saturated fats.
Mueller said maximizing rumen function that supports component production also can allow for more forage inclusion and help save on more expensive ingredients – like blood meal – that supply rumen bypass protein. In addition to favorable milk and butterfat production by including sugars, he has seen herds also experience a positive protein response, which he says is indicative of good amino acid production in the rumen.
And, like protein and fat sources, all sugar ingredients are not created equally. Mueller said most “Midwest” and “Northeast” dairy rations will post an analysis of 1-3% sugars, which come from fiber sources and are 5-carbon sugars that digest at a relatively slow 10% per hour. Molasses, on the other hand, is an added sugar that digests at 60% per hour. Mueller typically shoots for 5-7% added sugars, for a total sugar content of 7-9%.
Mueller said the cost of including sugar sources like molasses should be factored more on the nutritional function it serves, and less on a least-cost approach. Ishler concurred, noting the true measure of any feedstuff’s value should be income over feed cost per cow.
She advised monitoring ration modifications like including sugar via bulk-tank pickups, components, and milk urea nitrogen reports from the processor. Mueller also relies on milk fatty acid profiles, specifically looking at de novo fatty acid yield, which supports higher butterfat production.
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