In a new study, cows given a seratonin boost produced milk with more calcium.
Happy Cows, More Nutritious Milk
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California dairy producers have often claimed their goods superior because "happy cows come from California"—and as it turns out, they might be on to something. A new study has shown that cattle who have lived a happier life produce more nutritious milk. In a study published in the Journal of Endocrinology, researchers from the University of Wisconsin, Madison found that cows who were exposed to a chemical known to boost happiness produced milk with an increased level of calcium.

According to Science Daily, the hormone serotonin has long been used to relieve depression, as it's known to lift spirits. In order to test the effect of higher levels of serotonin on a cow's milk, researchers treated two breeds of bovine—Holstein and Jersey—with daily infusions of a chemical that converts into the happy hormone. Across all of the study specimens, the overall level of calcium in the cows rose. However, the two breeds were affected in different ways. While the Holstein cows had higher levels of calcium in their blood, and lower levels in their milk, the Jersey cows saw a spike in calcium in their milk specifically. "By studying two breeds we were able to see that regulation of calcium levels is different between the two," says Dr. Laura Hernandez, the study lead. "Serotonin raised blood calcium in the Holsteins, and milk calcium in the Jerseys."

This boost in calcium could be particularly important for the 5-10 percent of the American dairy cow population that has hypocalcaemia—a disorder that creates low calcium levels in the blood and milk, especially before and after giving birth. Beyond draining the animal's milk of its nutrients, hypocalcaemia can also lead to problems with the digestive and immune systems and decreased pregnancy rates.

While Hernandez and her team saw the impact of the chemical on the cows' calcium levels overall, the treatment "had no effect on milk yield, feed intake, or on levels of hormones required for lactation." However, for farmers whose cows' suffer from a lack of calcium, this research could lead to a healthier herd—and, for consumers, a larger nutritional payoff for their milk money.