Activity Monitors Offer Ways to Detect Heat, Increase Profits

11/9/2013 7:00 AM
By Philip Gruber Staff Writer

LANCASTER, Pa. — Out with the alphabet cows, in with collar sensors.

Heat detection has come a long way since 1988, when Ray Nebel, then a Virginia Tech researcher, ran a cow activity monitoring study using the best technology available — a surveillance camera with a grad student watching the feed.

In the grainy late-’80s footage, the ear tags were illegible and the Holsteins were indistinguishable, so Nebel’s team had to paint letters on the cows’ sides to determine which ones were in heat.

Today, every North American artificial insemination company is affiliated with an activity monitor using accelerometers and other high-tech sensors, said Nebel, now vice president of technical services at Select Sires and a presenter during a Penn State Extension precision dairy forum on Oct. 31 at the Farm and Home Center in Lancaster.

Nebel mentioned about a dozen ear and collar sensors that are on the market, noting that microchips have spurred an “explosion” of options for dairy farmers looking to tell more precisely and cost-effectively when their cows should be bred.

Cows tend to be unusually active in the narrow, several-hour window of estrus. Because farmers cannot always be around to see the subtle signs of heat, activity monitors, often mounted on ear tags or collars, help by identifying cows that are potentially in heat.

“Hopefully, you have better things to do at 9 p.m. than checking heat,” Nebel said, and activity monitors can give farmers a bit more freedom from the barn.

Every company uses its own tags, receivers or base stations, and proprietary software. Companies do not want farmers to be able to mix and match hardware from one company with software from another because that would require that manufacturers share their programs and components with their competitors, he said.

As a result, the systems all use different sensing methods. Dairymaster uses a true accelerometer, an instrument from the aerospace industry, while Nedap uses a pedometer.

And “they all have different algorithms” for tracking movement, Nebel said.

One Lely sensor shoots a strobe beam through a liquid-filled chamber. The device, made in Israel, measures the movement of the air bubble in the liquid — like a carpenter’s level with high-tech add-ons.

The University of Kentucky is currently testing sensors on seven different parts of a cow’s body to see which ones work best, he said.

As the technology has improved, companies’ claims have also inched skyward. GEA has touted 95 percent heat detection for its product, and BouMatic has said it can even beat that, Nebel said.

If the variability among products makes it seem like choosing an activity monitor could be almost impossible, Nebel does not see it that way.

The main differences that will affect a farmer’s experience are the software and the person who will service the system after the sale, he said. Farmers should choose the system with the data and interface that work best for them, and they should choose a company with a sales rep they trust to help them troubleshoot.

Rumination sensors are the next big thing, Nebel said. They measure how long a cow is chewing cud, giving an extra layer of data to indicate heat. Rumination tags may not be necessary for heifers, but the tags have the added bonus of flagging cows with potential health problems that make them want to chew less, Nebel said.

Activity monitors are not a panacea, however. “No matter what heat detection system you use, you’re still going to use some timed AI,” he said.

The system typically takes about two and a half years to pay for itself, and heifer systems are cheaper than cow systems, he said.

The United States has been slow to embrace activity systems — perhaps 1 percent of Pennsylvania dairies have adopted the technology —but that is changing, Nebel said.

“The last generation wasn’t interested in doing something different,” but the generation entering the business now is much more willing to experiment, he said. “Their free time is a lot more important.”

Three of those younger producers spoke at the forum and offered their insights on the precision dairy tools they use on their farms.

Tony Brubaker of Brubaker Farms in Mount Joy learned about Select Detect, Select Sires’ activity monitor system, during a farm visit with Nebel.

“Our cows were doing decently well with timed AI, but there was probably some room for improvement,” Brubaker said.

Brubaker’s herd manager liked the idea of not spending so much time watching for heat, but Brubaker wanted to make sure the new system would save not only labor but also money on shots.

“I like to be an early adopter but not a guinea pig,” he said.

Eventually he decided that the $17,000 for the heifer system could pay for itself in a year by cutting down three weeks of heifer feed costs. The system was installed in spring 2011.

The dairy’s pregnancy rate jumped from 32 percent to 45 percent in the new system’s first year. The heifer rate has since climbed to 54 percent.

Brubaker said he was breeding at 11 months and has pushed that back to 12 months while maintaining a 22-month average for calving. Freshening stayed constant between 21 and 23 months.

After the success of the precision heat detection system with the heifers, Brubaker wondered if the setup would work for his cows. At $64,000, though, the investment was much larger.

“Let’s try it on half the cows” and do a side-by-side trial, Brubaker decided. The system worked well enough to expand to the full herd.

Brubaker gives all cows timed AI as their first service and catches repeat animals with the activity monitors. Select Detect has improved Brubaker Farms’ services per conception to 1.4, he said.

Brubaker said he hoped the system would cut his drug costs by 75 percent. He was able to get most of the way to the goal, 67 percent. CIDR Synch expenses held him back somewhat from that goal. The pregnancy rate increased more than he expected, though, which helped make up the difference.

Precision dairy management offers more scheduling flexibility than shots, which require a block of several hours to administer to a herd. Precision technologies still require a lot of work, though.

“It’s kind of a trade-off,” Brubaker said.

Eric High built a free-stall barn in 2009 at his family’s Fredericksburg dairy. After making that improvement in cow comfort, High saw a precision heat detection system as the best way to improve his profitability. He agreed to be a Select Sires trial herd and put in a system in 2010.

High currently uses collars on about 35 percent of his cows. He sticks with the animals he is looking to breed. The batteries last about two and a half years and are fairly easy to change, he said.

Conceptions jumped from 32 percent to 54 percent between 2010 and 2013, and the pregnancy rate more than doubled from 13 to 28 percent over that time.

The days for first service fell from 98 to 91, and the average days open dropped from 172 to 116. The dairy’s services per pregnancy, previously at 3.1, now stand at 1.8. High’s dairy has produced so many heifers that they needed to build more housing for them.

Asked what he would do differently, High said, “I’d have put it in 10 years ago.”

Kurtland Farms in Elverson has put a particularly large amount of faith in precision dairy technologies. Trisha Dechert, the farm’s reproduction manager, said the 220-cow dairy added four robotic milkers in March and uses collars for 99 percent of heat detection.

While the other dairies use the more basic heat monitoring tags, Kurtland’s collars have rumination and activity monitoring functions.

The Kurtz family spent four years researching precision technologies. Though the robots are working well, it’s still too early to tell if the investment will be worth the cost, Dechert said.

As for the Lely responders on the cows’ necks, “you’re able to detect abnormalities more quickly,” Dechert said. The rumination tag helped catch a displaced abomasum, the cow’s fourth stomach.

The system showed Dechert that many of the cows were being bred too late. The software collects the time of day the cows are bred and suggests the optimum time for breeding.

Now “we breed them right away” when they show up on the high-activity list, she said.

Farmers need to make sure they put rumination collars on properly. Dechert’s collars have a sensor that must be on the left side of the cow’s neck where it can feel the movements of a muscle used in chewing.

The precision tags have improved the dairy’s conception rate and cut labor costs. The dairy is spending 70 to 80 percent less on shots. She has totally stopped pre-synchronization but continues to have a re-synchronization.

Still, precision technologies cannot replace paying attention to the herd.

One cow showed high activity 20 times in the past month. “She’s constantly nosy” and just more curious and active than other cows, Dechert said.

“You can’t just look at the computer” and breed every cow that shows up on the list, she said.

Nebel, of Select Sires, also said that high activity does not necessarily indicate heat. He once bet a farmer that he could put all of the man’s cows on the heat list in a day. Nebel let his English bulldog loose in the barn and watched the cows’ activity spike.

Select Detect, Select Sires’ activity monitoring system, was developed in Ireland, where cattle are primarily grazed. It had to be designed to create a whole-herd activity baseline to account for the high activity that occurs when cattle change paddocks.

Another farm’s ear tags gave false positives because the cows were constantly shaking their heads to ward off flies, he said.

Brubaker’s herd manager has moved the activity threshold lower for a related reason. The manager would rather decide not to breed a cow after looking at it than miss the heat entirely, Brubaker said.

Activity monitors can provide greater heat detection, but to be most effective, they must be paired with farming sense.


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