Activity monitors on heifers work very well on Gjerde Farm near Sunburg, Minn.  

Activity monitors, pedometers simplify heat detection

Forget tail chalk. Scribbled notes on your hand. Ovsynching each and every blessed cow. A new generation of activity monitors and pedometers is making heat detection a whole lot easier.

Ask Minnesota producer Paul Gjerde. Last Thanksgiving week, Gjerde ran 30 yearling heifers into his headlocks and strapped Select Detect activity monitors on their necks. "Within two weeks, all of them were detected in heat and bred," says Gjerde, who with his brother Kraig milks 300 cows near Sunburg, Minn.

Gjerde started using the monitors in April 2011. But already, he’s sold on the system. "We’ve saved thousands of dollars in synchronization drugs already. We estimate we’ll have the system paid for in 22 months," he says.

The activity monitors won’t totally eliminate synchronization programs on farms, acknowledges Casey Anderson, reproductive business manager for Select Sires, which markets the monitors. "But using the systems will identify cows that need to be synchronized," he says.

That percentage varies from farm to farm, with the average typically 15% to 20%, Anderson says. On Gjerde’s dairy, it’s less than 10%.

Gjerde places collars on fresh cows 30 to 40 days after calving. "By 45 to 50 days after calving, we’ll start to see activity spikes," he says.

Gjerde has a 58-day voluntary waiting period. If the pedometers pick up no activity by 78 days in milk, he will start the cow on an Ovsynch program to jump-start her ovaries.

With the system, Gjerde’s annualpregnancy rate is 18% to 20%. Before, using a full synchronization program, it had been running 22%. But the summer of 2011 was a brutal breeding season, and the herd’s pregnancy rate has since rebounded.

An automated heat detection program from Afimilk has been used by Jason Bradford of Sparta, Mich., for 10 years. He has not done any visual heat detection in that time, and his pregnancy rate is 24% on 1,300 cows.

"In summer, our pregnancy rate might dip to 18% or 20%. But we’ve also been as high as 29%," he says.

Bradford uses a sort gate to separate cows in heat after milking. Though he milks 3X, he inseminates mornings and evenings.

Bradford leaves the activity monitors on cows throughout lactation. The Afimilk monitors, which are now about $60 each, provide cow identification and alert him when activity drops below baseline as well.

"If her activity is down and she is off on milk, that usually means the cow is sick or lame," he says. "This system allows one person to do a lot of management without leaving the office."

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