Current Progressive Cattle digital edition

Put blood pregnancy test to work in your ET program

Jeremy Howard Published on 24 July 2012

A goal of many cattlemen is to maximize the genetic potential of their animals and tailor them to their production environment.

Many technologies and tools have been introduced over the years to help producers meet this goal.

Artificial insemination (AI) is a tool that is widely used today. Breeding cattle by AI versus by bull allows producers the opportunity to improve their herds by accessing sires with superior genetics from anywhere in the world.

Embryo transfer (ET) is another popular technology. This advanced reproductive tool allows producers the opportunity to produce more offspring from elite cows and extend the impact of these genetically superior animals.

Conventional ET work involves a donor cow or heifer being administered specific hormonal treatments over a set period of time.

These treatments initiate the production and eventual ovulation of multiple oocytes (unfertilized eggs). The donors are then bred using AI following estrus or standing heat.

Seven days following AI, embryos are removed or “flushed” from the donor animal’s uterus. The embryos are then analyzed for quality and either frozen (stored in liquid nitrogen) for use at a later date or transferred fresh into a recipient that has been synchronized to be at approximately the same stage of her estrus cycle as the donor animal.

This recipient will act as a surrogate mother for the resulting pregnancy. This process can be repeated every 28 to 60 days.

Another tool that can be used to increase the impact of genetically superior animals is in vitro fertilization (IVF).

IVF is the process of creating embryos from oocytes by fertilizing them with semen in a Petri dish. Oocytes can be collected from the ovaries of donors by ultrasound-guided follicular aspiration.

The oocytes are placed in a Petri dish, fertilized and then allowed to mature in an incubator for seven days.

Once the resulting embryos have matured they are transferred into the uterus of a recipient animal. Similar to ET, this recipient will act as a surrogate mother for the resulting pregnancy.

While many benefits exist with these reproduction technologies, two of the biggest challenges are cost and finding good recipient animals.

As a result, a high amount of management is required to maximize the return on investment.

One avenue that can be used to limit costs associated with the use of these reproductive technologies is to determine the pregnancy status of the recipient animal early after the embryo has been transplanted.

Options to detect pregnancy status early include palpation, ultrasound and blood pregnancy testing.

Pregnancy detection using palpation can be performed by a veterinarian or technician as early as 35 to 45 days post-breeding and at any time during pregnancy.

Ultrasound and blood-based pregnancy testing can be performed as soon as 28 days after breeding with increased accuracy over palpation.

Ultrasound has become more commonly available throughout the country over the past decade. This technology allows for the confirmation of both pregnancy as well as sex of the growing fetus (60 days post-breeding), though it requires a specially trained technician and equipment.

Blood-based testing for pregnancy is a relatively new technology that detects proteins produced by the placenta during pregnancy. Blood-based pregnancy testing is a cost-effective and accurate alternative to palpation and ultrasound.

Drawing blood for the pregnancy test is very simple. Using a new needle for each animal to avoid cross-contamination, a producer must draw at least 2 ml of blood per animal into a red-topped blood collection tube and label it sequentially with the animal’s identification number.

The samples can then be shipped without coolant to a local laboratory for analysis. Producers will receive results via email, fax, mail or phone five to 24 hours after the samples reach the lab. The test is 99 percent accurate when non-pregnant females are identified.

Randy McCabe from McCabe Genetics, Elk City, Kansas, uses blood-based pregnancy testing extensively in his herd’s heifer development and ET programs.

“Post-implant we want to get the animals on grass as soon as we can,” says McCabe. “Once the animals are out on grass we follow up with a cleanup bull almost immediately; this allows us to catch the recipient’s next cycle.

We use the blood pregnancy test on the recipient animals 25 to 30 days after implanting embryos and can determine which animals conceived to the ET without any interference from the bull-bred animals. This allows us to know which animals will be having ET calves.”

Nate Cossaboom, a veteran AI and embryo transfer technician, operates Bovine Genetics, LLC located in Fayette, Maine, and uses blood-based pregnancy testing in his customers’ herds to determine pregnancy status.

When asked why he used blood-based pregnancy, Nate replied, “It is a new tool that can be used to find open cows soon and get them re-bred. We can check the animals on a regular basis without schedule conflicts and determine pregnancy fairly inexpensively.”

Reducing the turnaround time for open females is a safe and effective way to improve the efficiency of a reproduction program.

Livestock producers who are able to use technologies to safely and accurately identify open females soon after breeding will be better able to improve the efficiency and success of their reproductive program.

For those producers using advanced reproductive programs like embryo transfer and in vitro fertilization, blood pregnancy testing is a tool that can help maximize return on investment.  end_mark

Jeremy Howard

Jeremy Howard
Reproduction Specialist
BioTracking, LLC