Evaluation of a Commercial Pregnancy Test Using Blood or Plasma Samples in High-Producing Dairy Cows

Area of Science:

• Veterinary reproduction
• Dairy cattle management
• Biotechnology in animal health

Background:

• Early pregnancy diagnosis is crucial for dairy herd management and reproductive efficiency.
• Pregnancy-associated glycoproteins (PAGs) are reliable biomarkers for pregnancy in ruminants.
• Evaluating new diagnostic tools for early detection is essential.

Purpose of the Study:

• To assess the efficacy of a commercial PAGs-based pregnancy test using whole blood and plasma in early-gestating dairy cows.
• To compare the diagnostic accuracy of blood versus plasma samples for PAGs detection.
• To investigate the influence of high milk production and estrus signs on test performance.

Main Methods:

• Evaluated a commercial PAGs assay on 284 high-producing dairy cows between 28-55 days of gestation.
• Utilized transrectal ultrasonography as the gold standard for pregnancy confirmation.
• Collected and analyzed both whole blood and plasma samples for PAGs presence.

Main Results:

• Plasma samples yielded 100% correct positive diagnoses, superior to blood samples (75%) in early pregnancy screening.
• False positive diagnoses occurred postpartum (Day 60-99 for plasma, Day 60-89 for blood).
• High milk production correlated with negative blood results and lower plasma test line intensity. No false results were observed in cows showing estrus signs after prior diagnosis.

Conclusions:

• Plasma is more effective than whole blood for early pregnancy diagnosis in dairy cows using PAGs tests.
• The PAGs test showed limitations in differentiating multiple pregnancies, recent fetal death, or pregnancy loss due to individual variations.
• Further research is needed to refine PAGs testing for complex pregnancy scenarios in high-producing dairy cows.