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Pregnancy Detection Goes High-Tech

Real-time ultrasound removes the guesswork.Real-time ultrasound (RTU) has the potential for near-perfect accuracy in sow pregnancy detection, according to industry analysts for the two machines on the market for hogs.If used properly, RTU can remove the guesswork of pregnancy detection, and along with it one of the biggest stumbling blocks to top reproductive efficiency.Estrus detection at 17 to 24

Real-time ultrasound removes the guesswork.

Real-time ultrasound (RTU) has the potential for near-perfect accuracy in sow pregnancy detection, according to industry analysts for the two machines on the market for hogs.

If used properly, RTU can remove the guesswork of pregnancy detection, and along with it one of the biggest stumbling blocks to top reproductive efficiency.

Estrus detection at 17 to 24 days after breeding remains the most common way to determine pregnancy status, explains Glen Almond, DVM, North Carolina State University (NCSU). The problem is accuracy. Producers relying on heat detection catch only 50-60% of open sows.

Almond points out that studies suggested back in the mid-1980s that RTU showed promise for early and accurate pregnancy diagnosis in sows and gilts. It didn't catch on largely because of its cost ($20,000 or more for a machine) and lack of mobility.

Today RTU is slowly starting to gain acceptance. The cost has come down and the machines are much more portable. The two units on the market sell for about $7,000 to $9,000.

Kurt Van Hulzen, DVM, Animal Health Center, Sac City, IA, was a big believer in the A-mode pregnancy detectors before switching to a RTU unit (also referred to as B-mode) almost a year ago.

A-mode system relies on amplification of sound waves reflecting off of fluid-filled structures. In this case, the system is looking for a pregnant uterus containing fetal fluid. A-mode units beep or a light flashes signaling the animal is pregnant. They only cost a few hundred dollars.

"The A-mode pregnancy units are very accurate in the 30- to 50-day range because the fluid sac in the sow is large enough that the machine will detect it," he says. But a recent visit to a client's farm assured Van Hulzen that the thousands he spent switching to RTU was the right choice.

This producer had been using an A-mode detector for years and knew what he was doing, he recalls. "He is a 1,000-sow producer with crated gestation, so he doesn't get a lot of sow movement when he is checking the sows."

But when Van Hulzen rechecked the producer's pregnancy detection work with RTU, he was surprised to find pregnancy status of seven out of 45 sows misdiagnosed (four false positives, three false negatives).

In contrast, when properly trained with B-mode RTU, 98%-plus accuracy can be attained, he says.

The RTU technology also uses sound waves to detect pregnancy, but they bounce off of tissue andbone instead of fluid. "The visual aspect of RTU gives the advantage of interpretation," explains Van Hulzen.

After placing the battery-operated probe on the sow's flank, directing it toward the uterus, an image is transmitted to a monitor, which provides visual evidence of the embryos inside.

"You are looking for big, walnut-sized follicles that almost look like swiss cheese," observes Van Hulzen. "The visual image tells you whether they are bred or not. It is definite. If you use the machine right, misdiagnosis is not a problem," he adds.

Working with RTU is also much faster than the A-mode units. "I'd say going from the A-mode to RTU easily cut our time of pregnancy detection in half because there are no more questions. We had so many borderline animals with the A-mode machine," says Van Hulzen.

Farrow-to-finish producer Lynn Garrels of Sac City, IA, had plenty of questions for Van Hulzen when he switched to the RTU detector. Van Hulzen did the pregnancy checking for Garrels using an A-mode machine until the farm staff took over. Within eight months, accuracy dipped significantly.

Two problems emerged. Farrowing rate was dropping, but conception rate, as detected by the staff, was not.

At first, he thought maybe the 20-year-old pen gestation facility was the problem.

So he started using the RTU unit, testing bred sows at 30 days and 40-45 days.

The RTU showed that there were many misdiagnosed animals between those two pregnancy testing periods. The staff was calling many animals bred that later "fell out," when in reality, they were not bred at all, he says.

With that information, Van Hulzen looked to the breeding herd. Noting that artificial insemination (AI) was used exclusively, he began by checking boar semen quality and identified it as the problem.

Garrels switched semen suppliers and, as a precaution, has gone to first-service natural mating followed by a second-service AI mating. So far, says Van Hulzen, performance has risen from a 50% farrowing rate to 75-80%.

RTU Lessons Like Van Hulzen, the staff of the 15,000-sow, 12-herd National Farms operation headquartered at Kersey, CO, harbored "strong skepticism about whether this RTU would work," reports Jerome Geiger, staff veterinarian.

"Quite frankly, today, no one on my team would go back. Everybody is sold on this technology," he says.

Switching from a dozen A-mode machines (one for each herd within the complex) to the one RTU unit took no time at all, Geiger says. Within an hour of company training, team managers were confident and ready to use the RTU.

One technician was assigned full-time to RTU duty and checks about 1,500-1,600 females each week. Bred females are checked at least twice, he says, at 25-35 days and again at 50-60 days.

With about one year of use under his belt, Geiger shares some valuable management lessons in terms of how to handle the staff and the machine that records don't show:

* The technician must have the right mental attitude. "Look for the open sows, not the pregnant sows, because those are the ones that are costing you money," says Geiger.

There is a temptation among staff to look for the pregnant females, calling those in doubt pregnant, too. That makes for a good, short-term conception rate - until the second pregnancy check shows her open. Geiger says, when in doubt, call her "open."

He observes, "Aggressively start heat checking that female. Let the boar and time prove you wrong. And, of course, check her again when in doubt."

* Build confidence in the RTU technician and then remove the A-mode machines to eliminate confusion and contradictions.

Unit managers at National Farms wanted to fall back on the A-mode units because the RTU was making them look bad, calling so-called pregnant sows open. But once the A-modes were removed, time proved the technician knew what he was doing, says Geiger.

* Make one technician responsible for RTU pregnancy detection. For consistency and ease of management, one person must be responsible for the program's success or failure.

* The RTU will not automatically lower non-productive sow days (NPSD). If you are doing a good job at 18-day heat checks and 30-35 day A-mode diagnostics, switching to RTU won't provide lower NPSD based on these early pregnancy fall-outs.

* Keep aggressively doing 18-day heat checks. Don't let breeding personnel rely too heavily on the RTU technician. Don't underestimate the importance of the "regular cycle" heat checks.

* Consider equipment modifications. Changes can make the RTU unit more personally suitable to the technician. Custom-made harnesses, protective equipment and probe extensions may be considered.

* Apply this technology to culling sows. In the past, pregnant sows were mistakenly culled because of the limitations of the A-mode machines. With RTU, sows are only culled if they are indeed "open."

* Prepare for the diagnostic challenges the RTU technology will bring. Veterinarians should be prepared to explain the 35-day pregnancies that fall-out before farrowing. Shortcomings of the A-mode will no longer be acceptable explanations. Some of the mystery may turn out to be PRRS (Porcine Reproductive and Respiratory Syndrome) or other non-breeding problems, says Geiger.

* Use what you learn through RTU to expand your knowledge of swine reproduction. When appropriate, veterinarians should conduct post-mortem examinations to confirm/explain RTU images.

Veterinarian Randy Larson of Alpha, IL, has found that sow examinations can help confirm findings and convince owners of the value of RTU.

He has been using RTU on four sow herds. He took the reproductive tracts out of some sows from each herd and all were confirmed as open as the RTU indicated.

Since RTU has been used, NPSD have improved every month. "We are making better culling decisions, because we definitely know that sow is open or pregnant, and we make a decision based on what we find," he says.

Fewer Non-Productive Days Lowering costly NPSD is one of the key benefits of the RTU technology, adds Van Hulzen. Some producers don't see what the big deal is about NPSD because they only consider the feed costs. "If you are feeding the sow 4-5 lb. a day and feed runs about 7 cents/lb., that's only 35 cents a day," he says. They forget about the sow costs for labor and facilities. In all, Van Hulzen figures NPSD runs about $1.50/day.

Table 1 depicts the savings you can achieve on NPSD depending on what value you place on open sows and the number of days of improvement.

The table shows that, based on a NPSD value of $1.50/sow, a 500-sow herd decreasing NPSD by 10 days could virtually pay for an RTU unit in one year.

"There aren't many pieces of equipment on a hog farm that have that fast a payback," says Van Hulzen. He figures the veterinary clinic at Sac City, IA, will have their RTU unit paid for in a year and a half.

He charges producer clients a per sow fee to cover the cost of owning and maintaining the ultrasound machine and charges his time separately. Depending on the operation, these costs run about $1.75-$2.00/sow.

Van Hulzen checks sows for his regular clients once at 30 days post-mating. For large farms, he will check sows twice, at 25-30 days and again at 50-60 days.

His visit to check sows provides other opportunities. "Besides pregnancy checking, we get another reason to be on the farm to review records and analyze why some sows have recycled and any other breeding problems the producer has been having," explains Van Hulzen.

Those records are one of the keys to really benefiting from using RTU, according to Bill Hollis, DVM, Carthage Veterinary Service, Ltd., Carthage, IL. "Essentially, the reason we use it is to make the pork production leaders get better.

"Certainly, we can go into a farm where there is poor heat detection and make changes with RTU. But you are not really helping them as much as you are finding the irregulars that otherwise would have spent 60 or so non-productive days in gestation," states Hollis.

RTU calls for responsibility. It makes a quick decision. If you mark the sow card as pregnant, she goes into gestation, he explains.

By the same token, on some farms managed by Hollis' clinic, sows identified as open are still in gestation two weeks later. It's good to reinforce the goal of using RTU to find known negatives and suspects. "But reinforce that something has to be done with these animals. If they are suspects, don't allow them to be ignored. They need to be evaluated by breeding barn personnel."

RTU's accuracy is what makes it so valuable. Females can be checked as early as 21days after mating, all the way up to farrowing, checking for mid-term or late-term fall-outs, remarks Hollis. Fall-out rates should not exceed 3% of the breeding herd, he says. If they do, there may be other problems involved.

Table 2 outlines the accuracy of RTU using two different types of probes and two different levels of power, based on field trial data compiled by NCSU.

The accuracy of RTU at varying stages of gestation, also from NCSU data, is compared in Table 3. RTU Market Options The two RTU units on the market for hogs are the "Real McCoy," from E.I. Medical and the Ultra Scan 45 from Alliance Medical U.S.A.

Pregnancy detection is a one-person task with both systems.

Base retail price for the "Real McCoy" is $7,900. It features video display glasses which directly receive the scanner image. The unit can also be used to measure sow backfat going into and exiting the farrowing crate. Four types of probes are available. An optional computer access card allows the user to save images on a removable card to be either reinserted for review or transferred to computer to be enhanced.

E.I. Medical maintains a high priority on service and training, says Tom Clark, sales manager.

The ability to limit downtime is important to producers. The "Real McCoy" is manufactured and sold direct from our facility in Colorado, points out Clark. "This helps us provide a quick turnaround time on all service work."

A lot of concern by producers is biosecurity, says Clark. The complete, self-contained unit cleans up well with a damp cloth, followed by a disinfectant spray. He recommends where there is only one scanner unit and several farm sites to be checked, that a carrying vest be kept at each site.

Available at World Pork Expo, E.I. Medical will offer a training video with operating instructions, including video of scanning done at various stages of gestation.

For more information on the "Real McCoy," contact E.I. Medical, 348 N. Jefferson Ave., Loveland, CO 80538; telephone: 970/669-1793; fax: 970/669-1902.

The Ultra Scan 45 offers a variety of different probes and is priced at $6,730. Alan Thilking of Alliance Medical says while pregnancy detection is the main thrust, units to measure backfat and loineye areas will be available in a few months.

Service is stressed. A fulltime technician can often provide same-day repair service. Loaner units are available. Used RTU units are also for sale at a reduced price.

A unit featuring video display glasses is expected to be introduced at World Pork Expo.

For more information, contact Alliance Medical U.S.A., 112 N. Bridge St., Box 404, Smithville, MO 64089; telephone: 816/532-4838; toll-free: 1-888/689-3070; fax: 816/873-3223.