Determining the breeding female’s pregnancy status is an important management tool in bovine herds, to identify which cows should be removed from the herd, and if estrous synchronization and artificial insemination attempts were successful. Ultrasonography offers many advantages over manual palpation, and makes this process more efficient and profitable. Our team at Mountain Legacy Veterinary Center breaks down how ultrasonography can improve your bovine reproductive management program.
How does ultrasound work?
Diagnostic ultrasound produces sound waves at high frequencies, above the human hearing threshold. A transducer, made from a special ceramic crystal material, produces these waves, and can also detect the ultrasound echoes that are reflected back. When an electric field is applied to the ceramic crystal material, they can produce not only the sound waves, but also an electric field when a sound wave hits them. During an ultrasound scan, the transducer sends out waves throughout the body. Boundaries between tissues in the beam’s path cause the transducer to reflect back the waves. These boundaries can be between fluid and tissue, or tissue and bone. The electrical signals produced are sent to the ultrasound scanner when these echoes hit the transducer. By calculating the distance between the transducer and the tissue boundary, a two-dimensional image is generated, detailing the tissues and organs. When performing a pregnancy evaluation in cows, the transducer probe is inserted in the cow’s rectum, to visualize the reproductive structures, the fetus, and fetal membranes.
How are ultrasounds beneficial for bovine reproductive management?
Ultrasonography performed by a bovine veterinarian allows for visualization and evaluation of the ovaries, uterus, reproductive vasculature, fetus, and surrounding structures. Benefits include:
- Detecting early pregnancy — Ultrasonography allows for pregnancy detection as early as 26 days post-breeding, which is seven days earlier than pregnancy diagnosis by manual palpation. Identifying open cows as soon as possible has the following advantages:
- Providing early detection of breeding and reproductive problems, including infertility in males and problem breeders in females
- Allowing for females to be sold or rebred if they are open
- Allowing for females to be separated and grouped based on pregnancy status, to better manage nutrition and management requirements
- Determining fetal viability — Fetal viability should be confirmed in the months following early pregnancy diagnosis. If embryonic reabsorption or fetal death occurs, early detection allows for rebreeding the open cow as soon as possible, which improves profitability. Fetal death indicators that ultrasound can identify include:
- Absence of fetal heartbeat or movement
- Presence of abnormal material in the amniotic or chorioallantoic fluid
- Separation of fetal membranes from the uterine wall
- Detecting twins — Twinning in cows is undesirable, because the situation typically results in higher rates of embryonic death and late-term abortion, premature calving, difficult calving, and metabolic disease complications, such as ketosis. Twins can be detected by ultrasound as early as 40 to 70 days post-breeding, allowing for management techniques, including culling, abortion and rebreeding, or continued monitoring until parturition.
- Fetal sexing — Ultrasonography can be used to accurately diagnose fetal sex from 55 to 90 days post ovulation. This can be useful for bovine herd management, for several reasons.
- Bred cow marketability — Heifer calves are more desirable in the dairy industry, but bull calves typically hold more value in the commercial beef market. When the fetal sex is known, this may increase the bred females’ value in a certain market.
- Freemartins — When a heifer and a bull are twinborn, the heifer is usually born infertile, because their shared blood supply in utero masculinizes the heifer with the bull’s male hormones. Ultrasonography allows for determining the twin’s sex, to know if a freemartin should be expected. This will help allow management decisions to be made early in the process.
- Management — Knowing how many bull and heifer calves are expected at calving can help the producer make future plans. If a producer retains breeding females, knowing the expected number of heifer calves will help determine if they need to purchase replacements. For producers who market bulls, negotiations to fill bull contracts can begin early. For purebred breeders selling a flush that guarantees a particular number of a specific gender, fetal sexing can determine if the agreement has been fulfilled, or the donor needs to be flushed again.
- Evaluating reproductive structures — The ovaries, uterus, and surrounding structures can be assessed to determine each cow’s reproductive status. Breeding timing can be optimized by following the cow’s estrous cycle by ultrasound. Ultrasonography is also useful in diagnosing abnormal reproductive conditions, including pyometra and cystic ovarian disease.
Ultrasonography is the best method to accurately diagnose pregnancy in bovines as early as possible. This procedure should be performed only by a trained bovine veterinarian, to avoid injuries, such as rectal tears, in your herd. If you would like your cows ultrasounded to assess pregnancy, do not hesitate to contact our team at Mountain Legacy Veterinary Center, so we can schedule a day that works best for you.