Assessment of Luteal Function Using Rectal Palpation, B-Mode Ultrasonography, and Progesterone Determination to...

Area of Science:

• Reproductive biology
• Veterinary science
• Livestock reproduction

Background:

• Embryo transfer (ET) success hinges on selecting suitable recipients.
• Accurate assessment of the corpus luteum (CL) is crucial for recipient selection.

Purpose of the Study:

• To evaluate rectal palpation (RP) accuracy versus ultrasonography (US) and progesterone (P4) for selecting recipients based on CL characteristics.
• To determine if US or P4 provide supplementary data for predicting pregnancy maintenance.
• To assess the reliability of CL cavity presence and ovarian CL volume (%CLOV) as ET outcome predictors.

Main Methods:

• Experiment 1: Assessed RP, CL dimensions (LADCL, MIDCL), CL area, and P4 in 94 heifers.
• Experiment 2: Evaluated US (CL volume, %CLOV, cavity presence), RP, and metabolic markers in 108 heifers.

Main Results:

• No significant differences were found in Experiment 1.
• Experiment 2 showed only a tendency for the veterinarian variable.
• RP and US are effective for recipient selection; US and P4 offer no additional predictive value for pregnancy.
• %CLOV and cavitary CL were not reliable indicators of pregnancy rates.

Conclusions:

• Rectal palpation and ultrasonography are valuable tools for selecting embryo transfer recipients.
• Ultrasonography and progesterone determination do not enhance the prediction of pregnancy maintenance beyond rectal palpation.
• Corpus luteum metrics like %CLOV and cavity presence are poor predictors of embryo transfer success.