Pregnancy Diagnosis: When? Why? How?
RUIDOSO, NEW MEXICO (Aug. 30, 2018) — When it comes to pregnancy diagnosis, Ky Pohler believes action is less important than method. The Texas A&M University animal scientist encourages all cow-calf producers to assess the pregnancy status of their herds following breeding season. There are multiple methods and no single way is best for everyone.
“The important thing is that you do it,” said Ky Pohler, Texas A&M, explaining the importance of pregnancy diagnosis to herd management.
“The important thing is that you do it,” stated Pohler while addressing an audience gathered for the Applied Reproductive Strategies in Beef Cattle workshop hosted Aug. 29-30 in Ruidoso. “The reason is because keeping a nonpregnant cow in the herd for an entire year accrues the same cost as a pregnant cow — as much as $850. However, the nonpregnant cow doesn’t produce anything.”
According to Pohler, knowing the pregnancy status of the herd can help make management decisions, such as adequacy of nutrition. It can help the producer evaluate the sires used and the efficiency of estrous synchronization and artificial insemination programs. It can also be used to determine how much pregnancy loss may be occurring and when.
“Still, only 20% to 25% of beef cows are pregnancy-diagnosed,” stated Pohler.
Ideally, explained Pohler, a pregnancy test is sensitive, accurate, simple and inexpensive. The ability to perform diagnosis early can also be advantageous. He described two types of tests: direct methods, which involve detecting the physical presence of a fetus, and indirect methods, which rely on markers that indicate the presence of pregnancy.
Pohler said the direct tests — rectal palpation of the uterus and ultrasonography – are the two most widely used methods of diagnosis. Manual palpation detects pregnancy by feeling for a fetus and associated structures, while ultrasonography provides a visual image. Both direct methods require a skilled technician, and ultrasonagraphy requires specific equipment.
Alternatively, chemical analysis of blood (or milk) samples provides indirect tests for pregnancy by detecting the presence of certain substances, such as pregnancy-associated glycoproteins (PAGs).
With regard to earliest possible diagnosis, Pohler said detection by palpation can be applied as early as Day 30 of pregnancy, while ultrasound examination may be used as early as Day 25. Testing for PAGs in the blood may be accomplished at Day 28.
“All of these methods are effective, so producers should choose a method that best suits their management system,” advised Pohler, adding that early detection of pregnancy will likely remain challenging because of early embryonic losses that may occur after pregnancy diagnosis.
For details on Pohler’s presentation — including the proceedings, PowerPoint and video of his presentation — visit the Newsroom at www.appliedreprostrategies.com.
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