Benefits of Ultrasound
Ultrasound is a powerful diagnostic tool when incorporated into a dairy’s reproductive management. It has the benefit of being able to visualize what is happening inside the uterus or ovaries. Currently there are 2 other diagnostic tools to assess the reproductive tract and diagnose pregnancy, those being rectal palpation and blood tests. Ultrasound is far superior, faster and cheaper ultimately in doing these things when performed by a skilled ultrasonographer than either rectal palpation or blood pregnancy tests.
Ultrasound benefits over rectal palpation:
- Ultrasound provides the ability to visualize the uterus, ovaries and developing fetus completely. With rectal palpation you are only palpating the surface of these structures and fetus/amnion. Ultrasound can identify a fetus that has just died (by observing the lack of a heart beat), which is impossible with rectal palpation. Palpators that claim to be able to diagnose pregnancies very early (less than 35 days) are only diagnosing fluid within the uterus. There can be many reasons for fluid within a uterus (dead fetus and pyometras), and not all are a viable fetus. Ultrasound can identify a viable fetus (fetus observed with a heart beat) reliably after 27 days, which makes misdiagnosis much less common.
Early viable fetus
45-Day Fetus with Color Doppler of Heart
Early dead fetus
- Because Ultrasound has the ability to visualize the ovaries completely, it is much easier and more reliable to diagnose ovarian cysts or the presence or absence of a corpus luteum (the structure on the ovary that produces progesterone and maintains pregnancies). This benefit can be used to help in a herd’s heat detection program. Since many herds utilize tail chalking for heat detection, there can be considerable mistakes (cows not in heat and potentially pregnant being inseminated). Using ultrasound, these cows can be scanned and cows that have CL’s are not inseminated, thus preventing a pregnant cow from being bred and aborted.
This benefit of being able to visualize all structures on the ovary also can be used to improve your timed AI program. Conception rates are maximized to these programs when cows synchronize completely to them, which is not always the case (as many as 40% of cows are not synchronized to a straight Ovsynch program). Using ultrasound, the dairy has the ability to ensure that cows are synchronizing in these programs before allowing them to be bred. The best day to determine this is on the day of the prostaglandin injection. If the cow has an active CL, she is more synchronized and should be allowed to continue through the timed AI program. If the cow does not have an active CL at this point, allowing her to continue through the program will result in very low conception rates (usually less than 15 percent). These cows can be restarted immediately or the following week plus or minus inserting a CIDR, which will result in conception rates of 35-50 percent.
Normal Corpus Luteum
Good Corpus Luteum
Two Good Corpora Lutea
Follicular Cyst – B
Cow in Estrus
Ovaries of cow that is synchronized within Ovsynch on the day of prostaglandin
- Ultrasound is also superior to rectal palpation in staging pregnancies, which is critical in bull breeding situations to ensure the cow is dried off at the appropriate time. With ultrasound you can visualize the fetus and measure structures which when compared to gestational charts give you very accurate age of the fetus.
- Ultrasound also is more effective at identifying twins than rectal palpation.
Fetuses at different stages
- Ultrasound can also be used to identify the sex of the fetus, which can be used to help make culling decisions on pregnant cattle. This can also be used when marketing springing heifers, either to retain heifers carrying females or sell them for a premium. Obviously rectal palpation cannot sex the fetus because one needs to visualize the fetus and reproductive structures.
- Ultrasound is superior to rectal palpation in the ease of training and reduced “wear and tear” on the ultrasonographer. Using ultrasound, the trainer is able to visualize what the trainee is doing, which helps in assisting the learning process. With ultrasound, usually there is no retraction of the uterus required, which results in much less strain on the neck, shoulder, elbow, and wrist, which reduces injury and prolongs the scanner’s career.
- Because of the reduced manipulation needed with ultrasound, there is much less chance of damaging the developing fetus.
Ultrasound benefits over pregnancy blood tests:
- With a pregnancy blood test, you are testing for a protein that is produced when there is a pregnancy. This protein lingers long after a fetus has died or a cow has calved, which will lead to calling many more cows pregnant than ultimately are. Ultrasound has the advantage of visualizing the fetus and determining viability (fetus has a heart beat) immediately and much more accurately.
- Blood pregnancy tests only tell you pregnant or open. How many times do you find cows pregnant to a previous breeding at your preg check? Blood pregnancy tests will never catch these mistakes, leading to drying cows much later than desired. Ultrasound will very easily identify these mistakes and ensure that the proper dry period is achieved. Also, if you have any bull bred cows, the blood pregnancy will not be able to stage these pregnancies, and you will have no idea when to dry these cows off.
- Blood pregnancy tests cannot identify problem cows, such as pyometras, follicular cysts, etc.. Ultrasound is able to instantly and easily identify these conditions and apply appropriate therapy.
- Blood pregnancy tests require drawing blood, sending off the samples, waiting for the test results, and then applying measures to get the cow rebred if found to be open. This requires many steps, which require extra labor and time. With ultrasound you are provided with more and better information instantly, allowing you to take steps to get the cow rebred much sooner if she is found open.