Do Spiced Up Rations Really Work?

Cows eating TMR. ( Farm Journal, Inc. )

New studies from Europe suggest spices—most notably garlic and oregano—can provide benefits beyond a more tasty TMR.

A field trial in the United Kinggom found that adding a 15-gram mix of garlic and citrus extract to milking rations reduced methane emissions by up to 38 percent. The study was done on a 400-cow dairy with a mixed herd of Holsteins and Jerseys and published by Scotland’s Rural College.

Dry matter intake did not differ, but milk production rose up to 8%, suggesting better feed efficiency. The supplement, marketed by Swiss-based Mootral, costs about $66/cow/year, or about 18₵/cow/day.

The supplement did not affect the taste or smell of the resulting milk. And garlic in the manure seemed to deter flies. The study can be found here.

In a second trial at the Sherbrooke Research and Development Center in Quebec, Canada, oregano oil and its main component, carvacrol, did not affect enteric methane production. In this study, just eight ruminally canulated lactating cows were used. The addition of the supplement did also not alter rumen fermentation or improve nutrient utilization or milk performance. The study can be found here.

In a third trial at the University of Reading in the United Kingdom, feeding oregano to baby calves reduced the level of antibiotic-resistant E. coli bacteria in their gut. A supplement, Orego-Stim Liquid containing oregano essential oil, was fed to a test group bull calves in waste milk for the first 10 days of their lives. A control group received no supplement.

After the 10-day feeding period, calves were then fed the same ration of untreated waste milk and concentrates until weaning. After weaning, feces of calves from both groups were tested for E. coli bacteria resistant to cephalosporin.

In the untreated calves, 44% of the E. coli present was resistant to cephalosporin. In the calves treated with Orego-Steim, just 12.6% of the E. coli were resistant.

“Oregano essential oil supplementation not only reduced the abundance of cefquinome-resistant E. coli, but also delayed the emergence of resistance to cefquinome,” says Partha Ray, a researcher at Reading.

“We are conducting further studies to understand the mechanism underlying the effect of Orego-Stim feeding on antimicrobial resistance in the gut of young cattle,” he says. “Improving our understanding of the mechanism is the only way we can refine the practice of feeding essential oil-based supplement to make it more sustainable.”

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