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New Mexico State University

New Mexico State University

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HeatWatch System Aids NMSU Researchers

LAS CRUCES - Keeping tabs on the fertility of more than 265,000 dairy cows isn't always easy for New Mexico's dairy producers. With the help of new technology, researchers at New Mexico State University have been working to help keep dairy herd numbers high.


"New Mexico ranks number one in dairy herd size in the U.S. right now," said Mike Looper, dairy specialist with NMSU's Cooperative Extension Service. "If we can find a way to increase the herd reproduction rate by as little as 10 percent, producers can benefit."

Researchers have been testing a radio telemetry system, known as HeatWatch, that helps producers detect when cows are most likely to conceive.

"This system allows researchers to observe the cattle 24 hours a day, seven days a week," Looper said.

Part of the system is a transmitter that is placed on the tailhead of the cow. When cows are fertile, the transmitter sends a signal to a nearby computer. Tracking the number of times the button is depressed helps producers choose the optimal time to artificially inseminate cows.

The system was tested at a dairy farm near Mesquite from May to August 2000. Scientists have found that the transmitter allows them to increase the conception rate.

Along with monitoring fertility, researchers wanted to determine if heat stress affects reproductive performance on dairy farms.

"We found that estrous activity, which is how cows act around one another when they are receptive to conceiving a calf, is decreased during the hotter times of the day," he said.

Looper's research found that transmitter activity decreased significantly between 10:30 a.m. and 5 p.m. Results showed that heat and humidity had a negative effect on reproduction of postpartum dairy cows. NMSU's findings will be presented at the American Dairy Science Association annual meeting in Indianapolis in July.

Scientists will be studying the system's potential with beef heifers in mid-April at a ranch in Reserve. The group will be using 50 to 75 transmitters on Angus replacement heifers. This time, the goal is synchronizing the births of the calves. By shortening the period when calves will be born, producers can reduce labor costs.

Having calves closer in age helps producers during calving and weaning because calves are more uniform in weight and size, Looper said.

"The system has been a great tool for our research and the fact that it is commercially available for producers is really an asset," he said.

The cost is close to $10,000 per 100 cows for the HeatWatch System, which was developed by DDx Inc. However, Looper says it can be used for several years, which would reduce the overall cost. He says developers have already come up with a new system.

"This new generation reduces cost per cow to approximately $50 because they've done away with the computer software," Looper said. "We will likely see future generations costing even less, making the system more commonplace on dairy and beef operations."