Scientists discover health benefits of melatonin supplement for livestock

Those who need extra sleep often reach for the bottle of melatonin, but Mississippi State scientists are uncovering a host of other proven and potential health benefits for cattle receiving the supplement.

Faculty and students at MSU’s Department of Animal and Dairy Sciences and the Mississippi Agricultural and Forestry Experiment Station are making intriguing discoveries about melatonin’s functions in the bovine body and how this hormone can help support livestock health.

MSU Associate Professor Caleb Lemley has a long history of studying the use of melatonin as a supplement in cattle. He has been studying how the hormone affects blood flow between the mother and fetus during gestation for nearly a decade.

“Over the years, we’ve looked at the antioxidant benefits of melatonin, which helps relieve oxidative stress in animals and has implications for their cardiovascular health,” Lemley said.

“Summer heat is a major stressor for livestock, and in our research here at the state of Mississippi, we discovered that melatonin has the potential to be used to control animal body temperature,” added Zully Contreras-Correa, associate postdoc. “At night, when melatonin levels are highest, body temperature is lowest. Our recent research has shown that melatonin supplementation during the summer reduces body temperature in pregnant cows, so we hope to research this further in other livestock species.

Because melatonin controls a body’s circadian rhythm and responds to light, levels also fluctuate throughout the year, naturally being highest in the winter and lowest in the summer.

“We just completed a study comparing melatonin supplements given to cattle living in Montana with our cattle at MSU during the winter months, and the differences were dramatic,” Lemley said. “We’ve seen a very limited response in Montana cattle compared to Mississippi cattle, so we think these treatments may be more effective in the Southeast.”

PhD students Riley Messman and Rebecca Swanson are also involved in melatonin research.

The scientists recently published a literature review in the journal Biomolecules entitled “Melatonin in health and disease: a perspective for livestock production”. These scientists reviewed more than 100 studies spanning six decades to demonstrate that this hormone naturally produced in the brain works in ways that go far beyond its basic function of regulating circadian rhythms.

One of the latest discoveries about melatonin involves its effects on the microbiome, the bacterial communities that live within the body. During her undergraduate studies, Messman conducted research examining its impact on the microbiome in the bovine vaginal tract.

“As melatonin levels fluctuate throughout the day and throughout the year, so do bacterial populations,” Messman said. “So, melatonin is altering the microbiome and the immune system, which plays a role in almost every physiological process you could think of.”

As part of his graduate work, Swanson studied the role of melatonin in skeletal muscle growth.

“Nutritional restriction occurs naturally in specific areas of the United States and at certain times of the year,” she said. “Melatonin may help alleviate some of that nutrient restriction and promote more efficient amino acid production and muscle growth.”

Because melatonin is considered a supplement and isn’t approved by the Food and Drug Administration, there has been a limited amount of research into its full effects and potential benefits. And while it’s currently a legal supplement for show animals, food animals may not legally receive melatonin supplementation. Lemley pointed out that trace amounts of the supplement are unlikely to be present in muscle tissue at the time of processing.

“Melatonin has a rapid elimination rate and will leave the body within a day,” she said. “When you consider this and the low cost of supplementing livestock at 25 cents a day, there are many potential benefits for producers.”

There is still much to discover about the far-reaching ways melatonin can support livestock health simply by manipulating levels of this naturally occurring hormone through supplementation. MSU scientists will continue their work for further discoveries on its benefits.