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Northern Valley Dairy Production Medicine Center


900 N. Wabasha, Plainview, Minnesota 55964 (507) 534-4356
Office Hours:

Monday-Friday
7:30 AM-5:00 PM

Saturday
8:00 AM-12:00 PM

​Sunday-Closed

24-hour Emergency Service
Ultrasound
What is Ultrasound?
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In its most basic definition, the term “ultrasound” refers to high frequency sound waves which are above the limit of human hearing. Much like submarines use sonar to send inaudible sounds into the ocean, medical and veterinary ultrasound machines generate high frequency sound waves which travel out of a probe. These sound waves bounce off of body tissues just like waves from a boat wake bounce off the shoreline of a lake. Return waves are generated, which the probe recovers and converts into a visible grayscale image. Tissues of different densities result in different returning waves, making them appear in distinct shades of gray in the image. The image is live, so motion such as a beating heart can be seen.
​Physicians have been using stationary ultrasound machines for “sonograms” during prenatal examinations for many years. Our practice purchased its first ultrasound machine back in 1989. However, the development in the 1990’s of portable, battery-powered machines has made the use of this technology by bovine veterinarians a practical reality. Each of our doctors is equipped with their own ultrasound machine. It is carried in a holder belted to the waist, and the image is viewed through a pair of goggles. There is no monitor, no cumbersome cart to carry around and clean up, and no need for electricity. In addition, trans-rectal ultrasound does not take any more time or cause any more stress to the cow than manual rectal palpation.
​Early Pregnancy Detection
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We have been extremely pleased with the quality of the images created by these portable units. A veterinarian experienced in the use of ultrasound can accurately diagnose pregnant vs. open at 28 days post-breeding in cows and 24 days post-breeding in heifers.
Fetus at 34 days
Fetus at 55 days
​Early pregnancy (and open) diagnosis is only one of the advantages of ultrasound examinations of the reproductive tract. Twins can be identified, allowing cows carrying twins to be marked for reexamination (because many twin pregnancies are naturally aborted) and managed differently to minimize calving problems, stillbirths, and postpartum metabolic disorders like ketosis, displaced abomasum, and fatty liver. A cow carrying twins typically calves seven to ten days early, so one needs to adjust her due date accordingly.
​Ovarian Structures
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Ovarian structures can be more accurately diagnosed with ultrasound than by palpation. This allows for precise decision-making on which animals to enroll in target breeding programs. For example, we know that cows without a corpus luteum (CL) over one centimeter in diameter will typically respond poorly to an Ovsynch program, and will not respond to a prostaglandin injection. By using ultrasound to identify a cow without a CL, the client will save money on injections and semen to breed a cow that is unlikely to conceive. Instead, the client can wait to observe a heat, have her re-examined at the next herd check, or use a CIDR to act as a substitute CL.
Corpus luteum
Cyst
​Uterine Pathology
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Endometritis, or inflammation of the uterine wall, is difficult to diagnose with manual rectal palpation. Cows with endometritis have very poor conception rates. Small pyometras may also be difficult to diagnose with palpation alone. A cow with a pyometra typically will not cycle. With ultrasound, these uterine pathologies can be easily diagnosed. Once diagnosed, these conditions can be addressed with treatment, resulting in an increased chance of conception and pregnancy.
Pyometra
​Embryonic Loss and Abortions
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Unfortunately over one-half of the cows that conceive and become pregnant will not stay pregnant. About 25% of pregnancies are lost in the first 28 days. The other 25% are lost after 28 days. Many people assume that all cows abort dead embryos or fetuses shortly after the death occurs. This is often not the case. Cows may take days to months to reabsorb or abort non-viable embryos and fetuses. In the meantime, the cow usually will not come into heat, so she is assumed to still be carrying a live calf! Ultrasound allows us to assess fetal viability by looking for a heartbeat and normal morphology. Dead embryos often appear small, incomplete, or poorly defined. Uterine fluid often looks flocculent, or whitish. Dead embryos can usually be removed by an injection of prostaglandin, allowing the cow more chances to become pregnant.
Dead fetus
​Fetal Sexing
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Fetal sexing can be performed with ultrasound from about 60 to 90 days of pregnancy. Most producers are not concerned about the sex of the fetus; they are just happy to have a pregnant cow. There are instances however, where it becomes important, and ultrasound is valuable in those instances.