Abstract
The objective of current study was to assess the trend in various luteal characteristics viz luteal size (LS), plasma progesterone (P(4)) concentration, and luteal blood flow (LBF) using color Doppler imaging (CDI) and power Doppler imaging (PDI) modes in pregnant and nonpregnant Nili-Ravi buffaloes. Lactating, cyclic, and healthy Nili-Ravi buffaloes (n = 09) without any reproductive abnormality were selected in present study. Buffaloes were synchronized using Ov-Synch, and fixed-time artificially insemination was performed (day = 0). Pregnancy was diagnosed on 30-day post-AI using B-mode ultrasonography based on presence or absence of embryonic heartbeat. Ovaries of all animals were scanned from day 5 till 21 post-AI using both B-mode and Doppler ultrasonography to measure LS and LBF. After each ovarian ultrasound examination, blood samples were collected via jugular venipuncture to determine plasma P(4) concentration. According to results, LBF using CDI and PDI was significantly higher (P ≤ 0.05) in pregnant buffaloes on days 13 and 15 post-AI, respectively. The mean LS and plasma P(4) concentration did not differ (P ≥ 0.05) between pregnant and nonpregnant animals until day 15 post-AI. However, a significant difference (P ≤ 0.05) was noticed for both on day 17 and onwards. It is concluded that LBF is a more sensitive luteal character as compared to LS and P(4) for earlier pregnancy diagnosis in Nili-Ravi buffaloes when ascertained through CDI.