Markers for early pregnancy prediction in Zebu females subjected to timed artificial insemination.

Mariana Alves de Silva; Artur Menezes; Endrigo de Araujo; Marcos Lima; Rodrigo Bittencourt; Marcus Loiola; Antonio Ribeiro Filho

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Markers for early pregnancy prediction in Zebu females subjected to timed artificial insemination.

Mariana Alves de Silva , Artur Menezes , Endrigo de Araujo, Marcos Lima, Rodrigo Bittencourt , Marcus Loiola, Antonio Ribeiro Filho

Abstract

Context: To increase the number of cows pregnant in the early breeding season, strategies have been developed, that seek to reduce the interval for pregnancy diagnosis. Aims: The aim of this study was to evaluate markers for the early detection of pregnancy in Zebu females. Methods: 175 Zebu cows were assessed at the time of insemination for the follicle diameter (FOLD), follicular wall area (FOLA) and follicle blood flow (FOLV). Twenty days after fixed-time artificial insemination (TAI), the corpus luteum was evaluated for diameter (CLD), area (CLA), vascularized area (CLV), and percentage of vascularization (%CLV). Blood samples were also collected to measure progesterone levels (P4D20). Based on FOLD, FOLV, CLD, CLV, and P4 as potential early pregnancy markers, the animals were categorized into two groups: negative predictive diagnosis of pregnancy (NPD) and positive predictive diagnosis (PPD). A definitive pregnancy diagnosis was performed 30 days post-TAI. Key results: Pregnant cows exhibited higher FOLD, FOLA, FOLV, CLD, CLA, CLV, %CLV, and P4D20 levels compared to non-pregnant cows. Significant correlations were found between FOLD and FOLA, FOLV, FOLV%,CLD, CLA, CLV, %CLV, and P4D20. FOLA was also significantly correlated with FOLV, CLD, CLA, CLV, %CLV, and P4D20. Similarly, FOLV was significantly correlated with FOLV%, CLD, CLA, CLV, %CLV, and P4D20. CLD correlated significantly with CLA, CLV, %CLV, and P4D20, while CLV showed significant correlations with %CLV and P4D20. Conclusions: The follicular and luteal morpho-functional characteristics are intricately linked to pregnancy establishment. Implications: The CLV emerged as a promising marker for achieving earlier pregnancy diagnoses.

RD25042 Accepted 02 July 2025