Product FAQ

How accurate are these instruments on swine?

RENCO® pregnancy testers are 100% accurate at 30 days and 95% at 25 days. With a properly designed testing program (testing every two-three days) and a skillful operator, they can be used as early as 18 days. Accuracy is about 85% for pregnant animals after two successive positive readings. 69% for open animals. Backfat readings are within 1mm from 3-30mm of fat plus skin.

How long does it take to learn to operate RENCO instruments?

Not very long! For example: Learning to do pregnancy detection on swine (and goats) takes about 15 minutes (at 30 days gestation) and backfat/loin about 30 minutes. To say it another way, the average operator can be proficient after examining at most 10 animals. Sheep take a little longer and Cattle the longest, about 3 hours or 75 head.

After I have become skillful, how long does it take to do a pregnancy test?

Testing at 30 days gestation takes 5-10 seconds for swine. Testing sheep at 42 days can be done in 30-60 seconds. Alpacas and goats about 5-30 seconds at 30-40 days. Cattle require about a minute at 90-100 days, or 3-5 minutes at 35-40 days, using the Preg-Alert Pro with the Deep Probe option.

Do RENCO pregnancy detectors need to be calibrated differently for use on animals other than swine?

The PREG-TONE® is shipped calibrated for use with swine, but the user can easily set it for use with other animals. The instrument cannot do cattle, mares or other large mammals at the very early detection sites. The operator can easily set the SONO-GRADER® and the PREG-ALERT PRO®for small, medium and large mammals.

Where and how do I test ewes for pregnancy at 25-40 days after mating?

Give no water for 8-12 hours prior, and try to have her urinate before testing. Sit the ewe on her tail. The test sites are up to 7cm (3 in.) outside the right and left teat lines, and in a straight line projected from the last rib—usually by the last teat. Start by working on the right side and try the left side if not successful. Remove hair from test site. Use plenty of coupling fluid and be sure to express all air bubbles by pushing in and moving it around. Aim the probe straight in, i.e. not at a 45° across the body as with swine, and do not allow probe to scan the bladder. To scan, slightly tilt and rock the probe around its axis. You cannot detect pregnancy at this stage in a standing animal. 

A farmer asks, “Well why can’t I just use my good boar on a rope, instead of spending money on a little box that buzzes?”

RENCO products are known for their durability. For over 30 years they have proven themselves able to withstand the adversities of a farm environment. Many of our instruments have been in service over 20 years. (Though we do not recommend such a test, the Preg-Tone has even withstood a barn fire!) Of course to assure long trouble free service, these instruments should be kept clean and not be subjected to abuse.

I am a swine producer. Why should I buy these instruments? What will they do for my business?

By detecting open sows early in the gestation period, you will be able to save feed and additive costs as well as the expense of vaccinations and special care normally given to pregnant sows. Early detection of pregnant sows will allow you to place them on your gestation program without delay. Early pregnancy detection is the way for you to increase your overall efficiency and lower your costs of doing business.

Is ultrasonic pregnancy testing successful on cattle, goats, and sheep?

Yes, and also on pygmy goats, horses, dogs, foxes, porpoise, seals, alpacas, llamas rabbits, dogs, and foxes, to name a few.

On what market animals has ultrasonic backfat or loin muscle depth measurements with RENCO products been successful?

Swine, cattle, and sheep. Ultrasonic breast depth testing has been used on turkeys and chickens. Fat pad depth measurement can be made on ostrich and emu. Though not market animals, blubber depth measurements have been made on the Harbour Porpoise, and we believe on seals.

A small group of us would like to share one of your instruments. What are your thoughts on this?

We strongly recommend against sharing because of the greatly increased possibility of disease transmission. Ideally, nothing coming in direct contact with one herd should come in contact with another. Good cold sterilization would seem to be a solution, but over time there will be instances where sterilization is not complete. Besides the probe and the cable, the instrument itself can become contaminated.

How do RENCO backfat products compare to the old metal ruler method?

They are inherently superior to the metal ruler method because they do not compress or distort the tissue. Because they are noninvasive, the potential for infection is greatly reduced.

I have just found that my pregnancy detector indicates males pregnant. Is it broken?

This question has been asked a surprising number of times. Trust us when we say that testing males for pregnancy is an exercise in futility, don’t do it. Males seemingly test pregnant because you have aimed the probe at the bladder that contains urine. To the instrument, this is the same as a uterus containing amniotic fluid.

I live in the U.S.A. How do I get the products repaired?

For warranty and other repair, just send the product by a traceable mode, prepaid to:

Renco Corporation
8830 7th Avenue N
Golden Valley, MN 55427

No RMA (Return Merchandise Authorization) or prior notification is necessary. Turnaround time usually runs about 3 business days. We make a reasonable attempt to reach you, but if you have not heard from us within 10 days after shipping, you should contact us. The information below is essential.

1) Your name and shipping address. Products are normally returned to you at your expense by UPS Ground. UPS does not deliver to P.O. Boxes. We need a street address or Rural Route number. Other methods are available at additional cost. 

2) Phone number where we can reach you between the weekday hours of 8:30am to 4:00pm, U.S. Central Time, or a fax number, or an email address.

I live outside of the U.S.A., how do I get my instruments repaired?

You should contact your dealer, a number of whom maintain service facilities. However, we will repair our current products when returned to us from anywhere in the world. Insurance is recommended. Be sure to include your postal address and fax number where we can reach you. Shipments must be sent to us prepaid including brokerage charges on our end.NOTE: We will not accept any shipment where charges are due. Invoices and other forms must include the statement (without the quotes), “Defective merchandise being returned to country of origin for repair and return to owner.” Description of merchandise must include the statement (without the quotes), “Electronic equipment for animal use.

What does servicing include?

In addition to repairing whatever problems we find, all instruments are calibrated and tested. 

Instruments are often returned to us in extremely dirty and contaminated condition. If you request it, we will restore the appearance of the instrument for an additional charge.

Are there any limits as to what can be repaired?

We do not promise to repair old versions of products for which parts are no longer available. Note: All products age, and with age may come a reduction in accuracy and reliability. We recommend that products be returned to us for calibration and testing at least once every three-years, oftener in cases where the instrument has been subjected to very rough handling.

When I return an instrument for repair, what else should I include?

For those units having a separate charger, probe, and probe cable, please include them.

If I need to replace wear and tear parts such as probes, probe cables, batteries, and chargers, do I need to return the instrument also?

For the PREG-ALERT® all of these parts can be replaced without sending the instrument to us. For all other products, all parts but the probe can be ordered without sending the entire product to us. (Probe replacement requires calibration.)

How do RENCO products use ultrasound?

These products are electronic rulers which measure the time it takes for ultrasonic pulses to go and return from various internal structures and converts this time into equivalent units of distance. Pregnancy is determined by the presence of amniotic fluid. Backfat and loin thickness are determined by the location of the tissues separating them. (For technical details, see the Technical FAQ.)

Why is it necessary to use coupling fluid?

Ultrasound must be transmitted through fluids or solids. Air inhibits transmission of ultrasound. The purpose of coupling fluid is to eliminate air between the transducer face and skin. The lack of a sufficient quantity of coupling fluid is by far the most common cause of problems reported to us. The fluid can be water, but it is better to use a somewhat heavier bodied material that will stay in place longer, such as ordinary cooking oil, glycerin, or mineral oil. NOTE: Avoid fluids that are acidic, alkaline, or that might contain additives with unknown properties, e.g. motor oil, as these may cause allergic reactions.There are commercial pH-neutral gels and creams that are specifically designed for use as ultrasonic coupling fluids, but these are costly and usually do not provide any significant advantage. There are also commercial wetting agents available, but for most situations these are not needed. The ability of the fluid to wet the skin is very important. This can be difficult when working with thick dry skin. When this condition is encountered, sometimes water can be used to wet the area and then oil applied over it, or a commercial wetting agent can be tried. Body hair is generally not a problem provided that enough coupling fluid is used to displace trapped air bubbles.

Besides insufficient coupling fluid, what are the most common reasons for incorrect pregnancy readings?

Pointing the probe at a urine-filled bladder will produce an erroneous result, because the instrument detects it in exactly the same way as it detects amniotic fluid in the uterus. Be sure the probe is not pointed in the direction of the bladder. Though not necessary in most cases, it may be helpful to have the animal urinate prior to the test. Errors in detection may also, result from pathologies that cause fluid to accumulate in the tissues.

Why do my backfat readings not agree with readings taken on slaughtered animals?

The tension in fat is relieved in slaughtered animals causing it to expand, adding on average about 1.3mm to the depth reading.

What do I need to know about the rechargeable batteries?

Some RENCO products use Nickel-Cadmium “NiCad” rechargeable batteries. These batteries will typically last 3-5 years, according to the intensity of use. A RENCO approved charger must be used to recharge them. Instruments should not remain connected to charger for extended periods. A battery that does not appear to hold a charge, can sometimes be revived by being fully charged (24-hours), then fully discharged for three consecutive cycles. Note: NiCad batteries should not remain in a fully discharged condition for extended periods. In such cases, it is possible that polarity reversal may occur, which will destroy the battery. Be sure to properly dispose of old batteries according to the laws of your area. 


What certifications have RENCO products earned?

All products have been certified under the applicable standards of the European Community EMC Directive. Those requiring U.S. FCC certification conform to Part 15 as Class A devices. Note: Our products are for use with animals. They are not licensed for human use and we strongly caution against using them on human beings.