Popis: |
The present study was conducted to evaluate the applicability of corpus luteum (CL) morphology and blood flow for early pregnancy diagnosis on Days 17-21 post-artificial insemination (AI) in Japanese Black (JB) cattle. Ultrasound examinations were performed on 230 inseminated JB cattle (202 cows and 28 heifers) to evaluate CL morphological characteristics [CL area, CL tissue area, presence/absence of a central cavity, and central cavity area (CCA)] and blood flow area (BFA) on Days 17 (n = 46), 18 (n = 45), 19 (n = 46), 20 (n = 47), and 21 (n = 46) (Day 0 = the day of AI). Pregnancy was confirmed using brightness-mode ultrasonography on Day 30. In pregnant group (n = 141), CL area and CL tissue area were greater (P 0.001) than those in non-pregnant group (n = 89) on and after Day 19. Moreover, BFA was greater (P 0.05) in pregnant group on and after Day 18. The overall central cavity incidence was lower (P 0.001) and CCA was smaller (P 0.001) in pregnant group. Logistic regression analyses revealed that the best single predictor for pregnancy diagnosis was BFA on Days 17-20 (sensitivity = 69%-100% and specificity = 65%-91%). On Day 21, CL area or CL tissue area was the most accurate predictor (cutoff value = 267.78 mm |