As any fish owner knows, keeping the fish tank and the water it holds clean is a key component of maintaining fish health. Fortunately, one can monitor many factors of the environment’s quality by looking at the color, aeration (bubbles), and debris of the water.

Air is to cows and people what water is to fish — a medium that we exist in, said Colorado State University’s Diego Manriquez, D.V.M. Monitoring air quality is a little more difficult than looking into a fish tank, but it is a good analogy for the importance of knowing what is going on in our environment, he said during a Dairy Cattle Welfare Council webinar.

Air quality is defined as the level of pollutants present in our medium which can be harmful for human and animal health and the environment, the dairy systems specialist said. That means we need to be able to track what pollutants exist in our environment. Air quality is not only a potential health risk but a component of welfare for both animals and people.

Manriquez first discussed what air is composed of: gases, chemicals, particulates, and microbes. There are also physical factors that can affect air quality such as temperature and humidity. Once those can be measured, we can determine what needs to be managed.

It is complex to measure air quality in dairy environments because they are semi-closed, often large, and involve human-animal interactions. However, it can be done, Manriquez said, particularly in the parlor, in barns, and around vehicles. He presented data from a study conducted at a 6,000-cow dairy, where sophisticated air quality sensors were installed in the center of the rotary parlor and in the tunnel-ventilated freestall barn to take measurements every minute.

Manriquez said that one conclusion they saw was how different the two spaces were. While methane readings were the same in both, ammonia levels and volatile organic compounds were higher in the barn and carbon monoxide was higher in the parlor.

Ammonia readings in the barn averaged 6.73 parts per billion (ppb), which Manriquez noted is much higher than the normal air levels of 1 or 5 ppb. Some research says higher levels can be harmful to human health, he added. They also saw ammonia levels peak overnight and then fall in the morning when the fans were turned on. While they thought ammonia levels would climb again during the day, that did not happen, so Manriquez said the tunnel ventilation was removing the chemical effectively.

Another interesting result was that methane was significantly higher than normal air would be. In both the parlor and the barn, there were three clear peaks in methane levels, Manriquez pointed out. In the barn, the peaks almost perfectly matched when animals were fed while in the parlor, they matched up with when milking was beginning or ending.

Manriquez recognized that the sensor they used had seriously degraded after five months and was not the best fit for farm use. Other options would have to be explored if dairies wanted to monitor air quality. But it is useful to know that air composition varies based on farm activities, and this may affect the welfare of the cows and people on the farm.