by Sally Colby

Ag technology is rapidly advancing, especially for dairy farms. While it’s tough for dairy farmers to consider spending money for something they may not be sure is right for them, there’s a good chance an activity monitoring system will save money over time.

Mat Haan, Penn State Dairy Extension educator, said the first reported use of a pedometer to measure cow activity associated with estrous was in the 1950s. “This isn’t brand new,” he said. “People have been working with these for quite a while, but over the past three years, they have started to become more common.”

Haan explained that activity systems use an accelerometer to measure vibrations or small changes in movement associated with cow activity – similar to the technology in a smartphone or video game. In addition to activity, many systems monitor rumen function, temperature, cow location in the barn, cow position (standing or lying) and eating time. Some systems also track panting, which is useful for measuring the level of heat stress.

Activity systems are comprised of three main parts: the activity tag attached to the cow, antennae in the barn and a computer (or smartphone) that displays the information collected.

There are several options for placing the activity monitor on the cow. Tags from early systems were placed on cows’ ankles, but today most are either collars or ear tags. Rumen boluses can also be placed to measure activity.

“The activity tag measures the cow’s movement and sends that information to the computer to report activity level,” said Haan. “Baseline activity level is determined for each animal. Once the tag is on a cow, it takes about a week or 10 days to get that cow’s baseline activity.”

If the activity level is outside the baseline, the system alerts and sends a message to the farm manager indicating that the cow’s activity is unusual. Higher than usual activity usually indicates heat; low activity can indicate illness. A combination of activity and rumination function can provide information on animal health. The dairyman uses activity data to make management decisions for either individual animals or groups of animals.

One of the main benefits of activity systems is improved breeding management and spotting early signs of health problems. There’s potential savings in feed costs due to reduced age at first calving, and savings in vet costs and added labor resulting from transition cow illness. Haan said some managers who use activity systems report that their system can detect a problem in a cow before it’s visible to the manager.

With decreased labor and less need to watch for estrous, and potentially less need for synchronization programs, Haan pointed out that an activity monitoring system is a tool and does not replace management, especially careful observation by a knowledgeable herdsman.

Activity monitors work for nearly every kind of dairy system, from freestall to tie stall to grazing. “If you’re grazing or using a tie stall barn, you’d change the settings and sensitivity as to what it picks up,” said Haan. “A cow in heat in a free stall barn is going to show heat differently than a cow in a tie stall barn because of the difference in moving around.”

Some of the challenges associated with activity monitoring systems include learning to use the technology, becoming familiar with the system and improving basic computer skills. Keeping the system up to date and making sure key employees are familiar with its use are critical for long-term success. “If you switch collars or tags from one animal to another, make sure you record that change,” said Haan. “Most systems can be accessed by computer or smartphone, and most also integrate with PCDART or other herd management software.”

Ideally, for the best picture of what’s going on your farm, every cow should have a tag. To cut costs, some farms use tags only on the breeding population for heat detection. “Tags would go on cows a few weeks after freshening until confirmed pregnant,” said Haan. “Once the cow is confirmed pregnant, the tag is used for another animal.” For more comprehensive health monitoring, Haan suggested tagging cows from pre-fresh through confirmed pregnant because the biggest chance for health problems is during the transition period. Having tags on well before calving allows the manager to collect data and determine “normal” prior to calving.

Activity systems vary in cost, from $80 for basic tags that supply activity information to around $165 for more comprehensive information. The antennae, computer and software can cost between $3,000 and $15,000, depending on the number of antennae needed to transmit information, the cost to install wiring and the complexity of the computer software.

Haan said it’s critical to calculate the return on investment (ROI) for an activity monitoring system. Companies that market activity monitoring systems can help farmers calculate the ROI and come up with a payment plan. Some of the factors considered include improved reproductive performance, lower costs to settle cows, labor efficiency, fewer metabolic disorders and increased milk yield. “However, the actual return on investment will depend on your existing reproduction program and how well the dairy integrates the technology into the management system,” said Haan. “If animals are 22 months at first calving and you’re getting mature cows bred with 45% to 50%, you may not see as much of a response and ROI as if your management was lacking.”

Prior to purchasing a system, Haan recommended finding out what kind of training and support is provided – does the company train users and explain how to interpret data? It’s also important to know the length of warranty on tags (typically three to five years) and other system components. Some systems process data off-site and require reliable internet that will operate 24/7, while others process data on the farm.

Understand how large an area the system will cover – will it collect and transmit information from pastured cows and cows in all parts of the barns? Make sure there are no “dead” spots in the barn where the system isn’t going to pick up whether a cow is in heat.

For those considering activity monitoring systems, Haan recommended visiting several dairy farms to see different systems are in use.

The University of Wisconsin has a program available to help dairy farmers integrate herd data to determine cost-effectiveness. Learn more at